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Commit 0d167518 authored by Linus Torvalds's avatar Linus Torvalds
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Merge branch 'for-3.5/core' of git://git.kernel.dk/linux-block 

Merge block/IO core bits from Jens Axboe:
 "This is a bit bigger on the core side than usual, but that is purely
  because we decided to hold off on parts of Tejun's submission on 3.4
  to give it a bit more time to simmer.  As a consequence, it's seen a
  long cycle in for-next.

  It contains:

   - Bug fix from Dan, wrong locking type.
   - Relax splice gifting restriction from Eric.
   - A ton of updates from Tejun, primarily for blkcg.  This improves
     the code a lot, making the API nicer and cleaner, and also includes
     fixes for how we handle and tie policies and re-activate on
     switches.  The changes also include generic bug fixes.
   - A simple fix from Vivek, along with a fix for doing proper delayed
     allocation of the blkcg stats."

Fix up annoying conflict just due to different merge resolution in
Documentation/feature-removal-schedule.txt

* 'for-3.5/core' of git://git.kernel.dk/linux-block: (92 commits)
  blkcg: tg_stats_alloc_lock is an irq lock
  vmsplice: relax alignement requirements for SPLICE_F_GIFT
  blkcg: use radix tree to index blkgs from blkcg
  blkcg: fix blkcg->css ref leak in __blkg_lookup_create()
  block: fix elvpriv allocation failure handling
  block: collapse blk_alloc_request() into get_request()
  blkcg: collapse blkcg_policy_ops into blkcg_policy
  blkcg: embed struct blkg_policy_data in policy specific data
  blkcg: mass rename of blkcg API
  blkcg: style cleanups for blk-cgroup.h
  blkcg: remove blkio_group->path[]
  blkcg: blkg_rwstat_read() was missing inline
  blkcg: shoot down blkgs if all policies are deactivated
  blkcg: drop stuff unused after per-queue policy activation update
  blkcg: implement per-queue policy activation
  blkcg: add request_queue->root_blkg
  blkcg: make request_queue bypassing on allocation
  blkcg: make sure blkg_lookup() returns %NULL if @q is bypassing
  blkcg: make blkg_conf_prep() take @pol and return with queue lock held
  blkcg: remove static policy ID enums
  ...
parents 2f83766d ff26eaad
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block/Kconfig.iosched
View file @ 0d167518
......@@ -23,8 +23,6 @@ config IOSCHED_DEADLINE
config IOSCHED_CFQ
tristate "CFQ I/O scheduler"
# If BLK_CGROUP is a module, CFQ has to be built as module.
depends on (BLK_CGROUP=m && m) || !BLK_CGROUP || BLK_CGROUP=y
default y
---help---
The CFQ I/O scheduler tries to distribute bandwidth equally
......@@ -34,8 +32,6 @@ config IOSCHED_CFQ
This is the default I/O scheduler.
Note: If BLK_CGROUP=m, then CFQ can be built only as module.
config CFQ_GROUP_IOSCHED
bool "CFQ Group Scheduling support"
depends on IOSCHED_CFQ && BLK_CGROUP
......
block/blk-cgroup.c
View file @ 0d167518
......@@ -11,1668 +11,906 @@
* Nauman Rafique <nauman@google.com>
*/
#include <linux/ioprio.h>
#include <linux/seq_file.h>
#include <linux/kdev_t.h>
#include <linux/module.h>
#include <linux/err.h>
#include <linux/blkdev.h>
#include <linux/slab.h>
#include "blk-cgroup.h"
#include <linux/genhd.h>
#include <linux/delay.h>
#include <linux/atomic.h>
#include "blk-cgroup.h"
#include "blk.h"
#define MAX_KEY_LEN 100
static DEFINE_SPINLOCK(blkio_list_lock);
static LIST_HEAD(blkio_list);
static DEFINE_MUTEX(blkcg_pol_mutex);
struct blkio_cgroup blkio_root_cgroup = { .weight = 2*BLKIO_WEIGHT_DEFAULT };
EXPORT_SYMBOL_GPL(blkio_root_cgroup);
struct blkcg blkcg_root = { .cfq_weight = 2 * CFQ_WEIGHT_DEFAULT };
EXPORT_SYMBOL_GPL(blkcg_root);
/* for encoding cft->private value on file */
#define BLKIOFILE_PRIVATE(x, val) (((x) << 16) | (val))
/* What policy owns the file, proportional or throttle */
#define BLKIOFILE_POLICY(val) (((val) >> 16) & 0xffff)
#define BLKIOFILE_ATTR(val) ((val) & 0xffff)
static struct blkcg_policy *blkcg_policy[BLKCG_MAX_POLS];
static inline void blkio_policy_insert_node(struct blkio_cgroup *blkcg,
struct blkio_policy_node *pn)
struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup)
{
list_add(&pn->node, &blkcg->policy_list);
return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
struct blkcg, css);
}
EXPORT_SYMBOL_GPL(cgroup_to_blkcg);
static inline bool cftype_blkg_same_policy(struct cftype *cft,
struct blkio_group *blkg)
static struct blkcg *task_blkcg(struct task_struct *tsk)
{
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
if (blkg->plid == plid)
return 1;
return 0;
return container_of(task_subsys_state(tsk, blkio_subsys_id),
struct blkcg, css);
}
/* Determines if policy node matches cgroup file being accessed */
static inline bool pn_matches_cftype(struct cftype *cft,
struct blkio_policy_node *pn)
struct blkcg *bio_blkcg(struct bio *bio)
{
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
int fileid = BLKIOFILE_ATTR(cft->private);
return (plid == pn->plid && fileid == pn->fileid);
if (bio && bio->bi_css)
return container_of(bio->bi_css, struct blkcg, css);
return task_blkcg(current);
}
EXPORT_SYMBOL_GPL(bio_blkcg);
/* Must be called with blkcg->lock held */
static inline void blkio_policy_delete_node(struct blkio_policy_node *pn)
static bool blkcg_policy_enabled(struct request_queue *q,
const struct blkcg_policy *pol)
{
list_del(&pn->node);
return pol && test_bit(pol->plid, q->blkcg_pols);
}
/* Must be called with blkcg->lock held */
static struct blkio_policy_node *
blkio_policy_search_node(const struct blkio_cgroup *blkcg, dev_t dev,
enum blkio_policy_id plid, int fileid)
/**
* blkg_free - free a blkg
* @blkg: blkg to free
*
* Free @blkg which may be partially allocated.
*/
static void blkg_free(struct blkcg_gq *blkg)
{
struct blkio_policy_node *pn;
list_for_each_entry(pn, &blkcg->policy_list, node) {
if (pn->dev == dev && pn->plid == plid && pn->fileid == fileid)
return pn;
}
int i;
return NULL;
}
if (!blkg)
return;
struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup)
{
return container_of(cgroup_subsys_state(cgroup, blkio_subsys_id),
struct blkio_cgroup, css);
}
EXPORT_SYMBOL_GPL(cgroup_to_blkio_cgroup);
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkg_policy_data *pd = blkg->pd[i];
struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk)
{
return container_of(task_subsys_state(tsk, blkio_subsys_id),
struct blkio_cgroup, css);
}
EXPORT_SYMBOL_GPL(task_blkio_cgroup);
if (!pd)
continue;
static inline void
blkio_update_group_weight(struct blkio_group *blkg, unsigned int weight)
{
struct blkio_policy_type *blkiop;
if (pol && pol->pd_exit_fn)
pol->pd_exit_fn(blkg);
list_for_each_entry(blkiop, &blkio_list, list) {
/* If this policy does not own the blkg, do not send updates */
if (blkiop->plid != blkg->plid)
continue;
if (blkiop->ops.blkio_update_group_weight_fn)
blkiop->ops.blkio_update_group_weight_fn(blkg->key,
blkg, weight);
kfree(pd);
}
kfree(blkg);
}
static inline void blkio_update_group_bps(struct blkio_group *blkg, u64 bps,
int fileid)
/**
* blkg_alloc - allocate a blkg
* @blkcg: block cgroup the new blkg is associated with
* @q: request_queue the new blkg is associated with
*
* Allocate a new blkg assocating @blkcg and @q.
*/
static struct blkcg_gq *blkg_alloc(struct blkcg *blkcg, struct request_queue *q)
{
struct blkio_policy_type *blkiop;
list_for_each_entry(blkiop, &blkio_list, list) {
/* If this policy does not own the blkg, do not send updates */
if (blkiop->plid != blkg->plid)
continue;
if (fileid == BLKIO_THROTL_read_bps_device
&& blkiop->ops.blkio_update_group_read_bps_fn)
blkiop->ops.blkio_update_group_read_bps_fn(blkg->key,
blkg, bps);
struct blkcg_gq *blkg;
int i;
if (fileid == BLKIO_THROTL_write_bps_device
&& blkiop->ops.blkio_update_group_write_bps_fn)
blkiop->ops.blkio_update_group_write_bps_fn(blkg->key,
blkg, bps);
}
}
/* alloc and init base part */
blkg = kzalloc_node(sizeof(*blkg), GFP_ATOMIC, q->node);
if (!blkg)
return NULL;
static inline void blkio_update_group_iops(struct blkio_group *blkg,
unsigned int iops, int fileid)
{
struct blkio_policy_type *blkiop;
blkg->q = q;
INIT_LIST_HEAD(&blkg->q_node);
blkg->blkcg = blkcg;
blkg->refcnt = 1;
list_for_each_entry(blkiop, &blkio_list, list) {
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
struct blkg_policy_data *pd;
/* If this policy does not own the blkg, do not send updates */
if (blkiop->plid != blkg->plid)
if (!blkcg_policy_enabled(q, pol))
continue;
if (fileid == BLKIO_THROTL_read_iops_device
&& blkiop->ops.blkio_update_group_read_iops_fn)
blkiop->ops.blkio_update_group_read_iops_fn(blkg->key,
blkg, iops);
/* alloc per-policy data and attach it to blkg */
pd = kzalloc_node(pol->pd_size, GFP_ATOMIC, q->node);
if (!pd) {
blkg_free(blkg);
return NULL;
}
if (fileid == BLKIO_THROTL_write_iops_device
&& blkiop->ops.blkio_update_group_write_iops_fn)
blkiop->ops.blkio_update_group_write_iops_fn(blkg->key,
blkg,iops);
blkg->pd[i] = pd;
pd->blkg = blkg;
}
}
/*
* Add to the appropriate stat variable depending on the request type.
* This should be called with the blkg->stats_lock held.
*/
static void blkio_add_stat(uint64_t *stat, uint64_t add, bool direction,
bool sync)
{
if (direction)
stat[BLKIO_STAT_WRITE] += add;
else
stat[BLKIO_STAT_READ] += add;
if (sync)
stat[BLKIO_STAT_SYNC] += add;
else
stat[BLKIO_STAT_ASYNC] += add;
}
/* invoke per-policy init */
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
/*
* Decrements the appropriate stat variable if non-zero depending on the
* request type. Panics on value being zero.
* This should be called with the blkg->stats_lock held.
*/
static void blkio_check_and_dec_stat(uint64_t *stat, bool direction, bool sync)
{
if (direction) {
BUG_ON(stat[BLKIO_STAT_WRITE] == 0);
stat[BLKIO_STAT_WRITE]--;
} else {
BUG_ON(stat[BLKIO_STAT_READ] == 0);
stat[BLKIO_STAT_READ]--;
}
if (sync) {
BUG_ON(stat[BLKIO_STAT_SYNC] == 0);
stat[BLKIO_STAT_SYNC]--;
} else {
BUG_ON(stat[BLKIO_STAT_ASYNC] == 0);
stat[BLKIO_STAT_ASYNC]--;
if (blkcg_policy_enabled(blkg->q, pol))
pol->pd_init_fn(blkg);
}
}
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* This should be called with the blkg->stats_lock held. */
static void blkio_set_start_group_wait_time(struct blkio_group *blkg,
struct blkio_group *curr_blkg)
{
if (blkio_blkg_waiting(&blkg->stats))
return;
if (blkg == curr_blkg)
return;
blkg->stats.start_group_wait_time = sched_clock();
blkio_mark_blkg_waiting(&blkg->stats);
return blkg;
}
/* This should be called with the blkg->stats_lock held. */
static void blkio_update_group_wait_time(struct blkio_group_stats *stats)
static struct blkcg_gq *__blkg_lookup(struct blkcg *blkcg,
struct request_queue *q)
{
unsigned long long now;
struct blkcg_gq *blkg;
if (!blkio_blkg_waiting(stats))
return;
blkg = rcu_dereference(blkcg->blkg_hint);
if (blkg && blkg->q == q)
return blkg;
/*
* Hint didn't match. Look up from the radix tree. Note that we
* may not be holding queue_lock and thus are not sure whether
* @blkg from blkg_tree has already been removed or not, so we
* can't update hint to the lookup result. Leave it to the caller.
*/
blkg = radix_tree_lookup(&blkcg->blkg_tree, q->id);
if (blkg && blkg->q == q)
return blkg;
now = sched_clock();
if (time_after64(now, stats->start_group_wait_time))
stats->group_wait_time += now - stats->start_group_wait_time;
blkio_clear_blkg_waiting(stats);
return NULL;
}
/* This should be called with the blkg->stats_lock held. */
static void blkio_end_empty_time(struct blkio_group_stats *stats)
/**
* blkg_lookup - lookup blkg for the specified blkcg - q pair
* @blkcg: blkcg of interest
* @q: request_queue of interest
*
* Lookup blkg for the @blkcg - @q pair. This function should be called
* under RCU read lock and is guaranteed to return %NULL if @q is bypassing
* - see blk_queue_bypass_start() for details.
*/
struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q)
{
unsigned long long now;
if (!blkio_blkg_empty(stats))
return;
WARN_ON_ONCE(!rcu_read_lock_held());
now = sched_clock();
if (time_after64(now, stats->start_empty_time))
stats->empty_time += now - stats->start_empty_time;
blkio_clear_blkg_empty(stats);
if (unlikely(blk_queue_bypass(q)))
return NULL;
return __blkg_lookup(blkcg, q);
}
EXPORT_SYMBOL_GPL(blkg_lookup);
void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
static struct blkcg_gq *__blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q)
__releases(q->queue_lock) __acquires(q->queue_lock)
{
unsigned long flags;
struct blkcg_gq *blkg;
int ret;
spin_lock_irqsave(&blkg->stats_lock, flags);
BUG_ON(blkio_blkg_idling(&blkg->stats));
blkg->stats.start_idle_time = sched_clock();
blkio_mark_blkg_idling(&blkg->stats);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_set_idle_time_stats);
WARN_ON_ONCE(!rcu_read_lock_held());
lockdep_assert_held(q->queue_lock);
void blkiocg_update_idle_time_stats(struct blkio_group *blkg)
{
unsigned long flags;
unsigned long long now;
struct blkio_group_stats *stats;
spin_lock_irqsave(&blkg->stats_lock, flags);
stats = &blkg->stats;
if (blkio_blkg_idling(stats)) {
now = sched_clock();
if (time_after64(now, stats->start_idle_time))
stats->idle_time += now - stats->start_idle_time;
blkio_clear_blkg_idling(stats);
/* lookup and update hint on success, see __blkg_lookup() for details */
blkg = __blkg_lookup(blkcg, q);
if (blkg) {
rcu_assign_pointer(blkcg->blkg_hint, blkg);
return blkg;
}
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_idle_time_stats);
void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
{
unsigned long flags;
struct blkio_group_stats *stats;
spin_lock_irqsave(&blkg->stats_lock, flags);
stats = &blkg->stats;
stats->avg_queue_size_sum +=
stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] +
stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE];
stats->avg_queue_size_samples++;
blkio_update_group_wait_time(stats);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_avg_queue_size_stats);
/* blkg holds a reference to blkcg */
if (!css_tryget(&blkcg->css))
return ERR_PTR(-EINVAL);
void blkiocg_set_start_empty_time(struct blkio_group *blkg)
{
unsigned long flags;
struct blkio_group_stats *stats;
/* allocate */
ret = -ENOMEM;
blkg = blkg_alloc(blkcg, q);
if (unlikely(!blkg))
goto err_put;
spin_lock_irqsave(&blkg->stats_lock, flags);
stats = &blkg->stats;
/* insert */
ret = radix_tree_preload(GFP_ATOMIC);
if (ret)
goto err_free;
if (stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_READ] ||
stats->stat_arr[BLKIO_STAT_QUEUED][BLKIO_STAT_WRITE]) {
spin_unlock_irqrestore(&blkg->stats_lock, flags);
return;
spin_lock(&blkcg->lock);
ret = radix_tree_insert(&blkcg->blkg_tree, q->id, blkg);
if (likely(!ret)) {
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
list_add(&blkg->q_node, &q->blkg_list);
}
spin_unlock(&blkcg->lock);
/*
* group is already marked empty. This can happen if cfqq got new
* request in parent group and moved to this group while being added
* to service tree. Just ignore the event and move on.
*/
if(blkio_blkg_empty(stats)) {
spin_unlock_irqrestore(&blkg->stats_lock, flags);
return;
}
radix_tree_preload_end();
stats->start_empty_time = sched_clock();
blkio_mark_blkg_empty(stats);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
if (!ret)
return blkg;
err_free:
blkg_free(blkg);
err_put:
css_put(&blkcg->css);
return ERR_PTR(ret);
}
EXPORT_SYMBOL_GPL(blkiocg_set_start_empty_time);
void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue)
{
blkg->stats.dequeue += dequeue;
}
EXPORT_SYMBOL_GPL(blkiocg_update_dequeue_stats);
#else
static inline void blkio_set_start_group_wait_time(struct blkio_group *blkg,
struct blkio_group *curr_blkg) {}
static inline void blkio_end_empty_time(struct blkio_group_stats *stats) {}
#endif
void blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction,
bool sync)
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q)
{
unsigned long flags;
spin_lock_irqsave(&blkg->stats_lock, flags);
blkio_add_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED], 1, direction,
sync);
blkio_end_empty_time(&blkg->stats);
blkio_set_start_group_wait_time(blkg, curr_blkg);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
/*
* This could be the first entry point of blkcg implementation and
* we shouldn't allow anything to go through for a bypassing queue.
*/
if (unlikely(blk_queue_bypass(q)))
return ERR_PTR(blk_queue_dead(q) ? -EINVAL : -EBUSY);
return __blkg_lookup_create(blkcg, q);
}
EXPORT_SYMBOL_GPL(blkiocg_update_io_add_stats);
EXPORT_SYMBOL_GPL(blkg_lookup_create);
void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync)
static void blkg_destroy(struct blkcg_gq *blkg)
{
unsigned long flags;
struct request_queue *q = blkg->q;
struct blkcg *blkcg = blkg->blkcg;
spin_lock_irqsave(&blkg->stats_lock, flags);
blkio_check_and_dec_stat(blkg->stats.stat_arr[BLKIO_STAT_QUEUED],
direction, sync);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
lockdep_assert_held(q->queue_lock);
lockdep_assert_held(&blkcg->lock);
void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time,
unsigned long unaccounted_time)
{
unsigned long flags;
spin_lock_irqsave(&blkg->stats_lock, flags);
blkg->stats.time += time;
#ifdef CONFIG_DEBUG_BLK_CGROUP
blkg->stats.unaccounted_time += unaccounted_time;
#endif
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
/* Something wrong if we are trying to remove same group twice */
WARN_ON_ONCE(list_empty(&blkg->q_node));
WARN_ON_ONCE(hlist_unhashed(&blkg->blkcg_node));
/*
* should be called under rcu read lock or queue lock to make sure blkg pointer
* is valid.
*/
void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync)
{
struct blkio_group_stats_cpu *stats_cpu;
unsigned long flags;
radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
list_del_init(&blkg->q_node);
hlist_del_init_rcu(&blkg->blkcg_node);
/*
* Disabling interrupts to provide mutual exclusion between two
* writes on same cpu. It probably is not needed for 64bit. Not
* optimizing that case yet.
* Both setting lookup hint to and clearing it from @blkg are done
* under queue_lock. If it's not pointing to @blkg now, it never
* will. Hint assignment itself can race safely.
*/
local_irq_save(flags);
stats_cpu = this_cpu_ptr(blkg->stats_cpu);
u64_stats_update_begin(&stats_cpu->syncp);
stats_cpu->sectors += bytes >> 9;
blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICED],
1, direction, sync);
blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_SERVICE_BYTES],
bytes, direction, sync);
u64_stats_update_end(&stats_cpu->syncp);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_dispatch_stats);
void blkiocg_update_completion_stats(struct blkio_group *blkg,
uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
{
struct blkio_group_stats *stats;
unsigned long flags;
unsigned long long now = sched_clock();
spin_lock_irqsave(&blkg->stats_lock, flags);
stats = &blkg->stats;
if (time_after64(now, io_start_time))
blkio_add_stat(stats->stat_arr[BLKIO_STAT_SERVICE_TIME],
now - io_start_time, direction, sync);
if (time_after64(io_start_time, start_time))
blkio_add_stat(stats->stat_arr[BLKIO_STAT_WAIT_TIME],
io_start_time - start_time, direction, sync);
spin_unlock_irqrestore(&blkg->stats_lock, flags);
}
EXPORT_SYMBOL_GPL(blkiocg_update_completion_stats);
/* Merged stats are per cpu. */
void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
bool sync)
{
struct blkio_group_stats_cpu *stats_cpu;
unsigned long flags;
if (rcu_dereference_raw(blkcg->blkg_hint) == blkg)
rcu_assign_pointer(blkcg->blkg_hint, NULL);
/*
* Disabling interrupts to provide mutual exclusion between two
* writes on same cpu. It probably is not needed for 64bit. Not
* optimizing that case yet.
* Put the reference taken at the time of creation so that when all
* queues are gone, group can be destroyed.
*/
local_irq_save(flags);
stats_cpu = this_cpu_ptr(blkg->stats_cpu);
u64_stats_update_begin(&stats_cpu->syncp);
blkio_add_stat(stats_cpu->stat_arr_cpu[BLKIO_STAT_CPU_MERGED], 1,
direction, sync);
u64_stats_update_end(&stats_cpu->syncp);
local_irq_restore(flags);
blkg_put(blkg);
}
EXPORT_SYMBOL_GPL(blkiocg_update_io_merged_stats);
/*
* This function allocates the per cpu stats for blkio_group. Should be called
* from sleepable context as alloc_per_cpu() requires that.
/**
* blkg_destroy_all - destroy all blkgs associated with a request_queue
* @q: request_queue of interest
*
* Destroy all blkgs associated with @q.
*/
int blkio_alloc_blkg_stats(struct blkio_group *blkg)
{
/* Allocate memory for per cpu stats */
blkg->stats_cpu = alloc_percpu(struct blkio_group_stats_cpu);
if (!blkg->stats_cpu)
return -ENOMEM;
return 0;
}
EXPORT_SYMBOL_GPL(blkio_alloc_blkg_stats);
void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid)
static void blkg_destroy_all(struct request_queue *q)
{
unsigned long flags;
spin_lock_irqsave(&blkcg->lock, flags);
spin_lock_init(&blkg->stats_lock);
rcu_assign_pointer(blkg->key, key);
blkg->blkcg_id = css_id(&blkcg->css);
hlist_add_head_rcu(&blkg->blkcg_node, &blkcg->blkg_list);
blkg->plid = plid;
spin_unlock_irqrestore(&blkcg->lock, flags);
/* Need to take css reference ? */
cgroup_path(blkcg->css.cgroup, blkg->path, sizeof(blkg->path));
blkg->dev = dev;
}
EXPORT_SYMBOL_GPL(blkiocg_add_blkio_group);
struct blkcg_gq *blkg, *n;
static void __blkiocg_del_blkio_group(struct blkio_group *blkg)
{
hlist_del_init_rcu(&blkg->blkcg_node);
blkg->blkcg_id = 0;
}
lockdep_assert_held(q->queue_lock);
/*
* returns 0 if blkio_group was still on cgroup list. Otherwise returns 1
* indicating that blk_group was unhashed by the time we got to it.
*/
int blkiocg_del_blkio_group(struct blkio_group *blkg)
{
struct blkio_cgroup *blkcg;
unsigned long flags;
struct cgroup_subsys_state *css;
int ret = 1;
list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
struct blkcg *blkcg = blkg->blkcg;
rcu_read_lock();
css = css_lookup(&blkio_subsys, blkg->blkcg_id);
if (css) {
blkcg = container_of(css, struct blkio_cgroup, css);
spin_lock_irqsave(&blkcg->lock, flags);
if (!hlist_unhashed(&blkg->blkcg_node)) {
__blkiocg_del_blkio_group(blkg);
ret = 0;
}
spin_unlock_irqrestore(&blkcg->lock, flags);
spin_lock(&blkcg->lock);
blkg_destroy(blkg);
spin_unlock(&blkcg->lock);
}
rcu_read_unlock();
return ret;
}
EXPORT_SYMBOL_GPL(blkiocg_del_blkio_group);
/* called under rcu_read_lock(). */
struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key)
static void blkg_rcu_free(struct rcu_head *rcu_head)
{
struct blkio_group *blkg;
struct hlist_node *n;
void *__key;
hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
__key = blkg->key;
if (__key == key)
return blkg;
}
return NULL;
blkg_free(container_of(rcu_head, struct blkcg_gq, rcu_head));
}
EXPORT_SYMBOL_GPL(blkiocg_lookup_group);
static void blkio_reset_stats_cpu(struct blkio_group *blkg)
void __blkg_release(struct blkcg_gq *blkg)
{
struct blkio_group_stats_cpu *stats_cpu;
int i, j, k;
/* release the extra blkcg reference this blkg has been holding */
css_put(&blkg->blkcg->css);
/*
* Note: On 64 bit arch this should not be an issue. This has the
* possibility of returning some inconsistent value on 32bit arch
* as 64bit update on 32bit is non atomic. Taking care of this
* corner case makes code very complicated, like sending IPIs to
* cpus, taking care of stats of offline cpus etc.
* A group is freed in rcu manner. But having an rcu lock does not
* mean that one can access all the fields of blkg and assume these
* are valid. For example, don't try to follow throtl_data and
* request queue links.
*
* reset stats is anyway more of a debug feature and this sounds a
* corner case. So I am not complicating the code yet until and
* unless this becomes a real issue.
* Having a reference to blkg under an rcu allows acess to only
* values local to groups like group stats and group rate limits
*/
for_each_possible_cpu(i) {
stats_cpu = per_cpu_ptr(blkg->stats_cpu, i);
stats_cpu->sectors = 0;
for(j = 0; j < BLKIO_STAT_CPU_NR; j++)
for (k = 0; k < BLKIO_STAT_TOTAL; k++)
stats_cpu->stat_arr_cpu[j][k] = 0;
}
call_rcu(&blkg->rcu_head, blkg_rcu_free);
}
EXPORT_SYMBOL_GPL(__blkg_release);
static int
blkiocg_reset_stats(struct cgroup *cgroup, struct cftype *cftype, u64 val)
static int blkcg_reset_stats(struct cgroup *cgroup, struct cftype *cftype,
u64 val)
{
struct blkio_cgroup *blkcg;
struct blkio_group *blkg;
struct blkio_group_stats *stats;
struct blkcg *blkcg = cgroup_to_blkcg(cgroup);
struct blkcg_gq *blkg;
struct hlist_node *n;
uint64_t queued[BLKIO_STAT_TOTAL];
int i;
#ifdef CONFIG_DEBUG_BLK_CGROUP
bool idling, waiting, empty;
unsigned long long now = sched_clock();
#endif
blkcg = cgroup_to_blkio_cgroup(cgroup);
mutex_lock(&blkcg_pol_mutex);
spin_lock_irq(&blkcg->lock);
/*
* Note that stat reset is racy - it doesn't synchronize against
* stat updates. This is a debug feature which shouldn't exist
* anyway. If you get hit by a race, retry.
*/
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
spin_lock(&blkg->stats_lock);
stats = &blkg->stats;
#ifdef CONFIG_DEBUG_BLK_CGROUP
idling = blkio_blkg_idling(stats);
waiting = blkio_blkg_waiting(stats);
empty = blkio_blkg_empty(stats);
#endif
for (i = 0; i < BLKIO_STAT_TOTAL; i++)
queued[i] = stats->stat_arr[BLKIO_STAT_QUEUED][i];
memset(stats, 0, sizeof(struct blkio_group_stats));
for (i = 0; i < BLKIO_STAT_TOTAL; i++)
stats->stat_arr[BLKIO_STAT_QUEUED][i] = queued[i];
#ifdef CONFIG_DEBUG_BLK_CGROUP
if (idling) {
blkio_mark_blkg_idling(stats);
stats->start_idle_time = now;
}
if (waiting) {
blkio_mark_blkg_waiting(stats);
stats->start_group_wait_time = now;
}
if (empty) {
blkio_mark_blkg_empty(stats);
stats->start_empty_time = now;
}
#endif
spin_unlock(&blkg->stats_lock);
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
/* Reset Per cpu stats which don't take blkg->stats_lock */
blkio_reset_stats_cpu(blkg);
if (blkcg_policy_enabled(blkg->q, pol) &&
pol->pd_reset_stats_fn)
pol->pd_reset_stats_fn(blkg);
}
}
spin_unlock_irq(&blkcg->lock);
mutex_unlock(&blkcg_pol_mutex);
return 0;
}
static void blkio_get_key_name(enum stat_sub_type type, dev_t dev, char *str,
int chars_left, bool diskname_only)
static const char *blkg_dev_name(struct blkcg_gq *blkg)
{
snprintf(str, chars_left, "%d:%d", MAJOR(dev), MINOR(dev));
chars_left -= strlen(str);
if (chars_left <= 0) {
printk(KERN_WARNING
"Possibly incorrect cgroup stat display format");
return;
}
if (diskname_only)
return;
switch (type) {
case BLKIO_STAT_READ:
strlcat(str, " Read", chars_left);
break;
case BLKIO_STAT_WRITE:
strlcat(str, " Write", chars_left);
break;
case BLKIO_STAT_SYNC:
strlcat(str, " Sync", chars_left);
break;
case BLKIO_STAT_ASYNC:
strlcat(str, " Async", chars_left);
break;
case BLKIO_STAT_TOTAL:
strlcat(str, " Total", chars_left);
break;
default:
strlcat(str, " Invalid", chars_left);
}
/* some drivers (floppy) instantiate a queue w/o disk registered */
if (blkg->q->backing_dev_info.dev)
return dev_name(blkg->q->backing_dev_info.dev);
return NULL;
}
static uint64_t blkio_fill_stat(char *str, int chars_left, uint64_t val,
struct cgroup_map_cb *cb, dev_t dev)
/**
* blkcg_print_blkgs - helper for printing per-blkg data
* @sf: seq_file to print to
* @blkcg: blkcg of interest
* @prfill: fill function to print out a blkg
* @pol: policy in question
* @data: data to be passed to @prfill
* @show_total: to print out sum of prfill return values or not
*
* This function invokes @prfill on each blkg of @blkcg if pd for the
* policy specified by @pol exists. @prfill is invoked with @sf, the
* policy data and @data. If @show_total is %true, the sum of the return
* values from @prfill is printed with "Total" label at the end.
*
* This is to be used to construct print functions for
* cftype->read_seq_string method.
*/
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
u64 (*prfill)(struct seq_file *,
struct blkg_policy_data *, int),
const struct blkcg_policy *pol, int data,
bool show_total)
{
blkio_get_key_name(0, dev, str, chars_left, true);
cb->fill(cb, str, val);
return val;
}
struct blkcg_gq *blkg;
struct hlist_node *n;
u64 total = 0;
spin_lock_irq(&blkcg->lock);
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node)
if (blkcg_policy_enabled(blkg->q, pol))
total += prfill(sf, blkg->pd[pol->plid], data);
spin_unlock_irq(&blkcg->lock);
if (show_total)
seq_printf(sf, "Total %llu\n", (unsigned long long)total);
}
EXPORT_SYMBOL_GPL(blkcg_print_blkgs);
static uint64_t blkio_read_stat_cpu(struct blkio_group *blkg,
enum stat_type_cpu type, enum stat_sub_type sub_type)
/**
* __blkg_prfill_u64 - prfill helper for a single u64 value
* @sf: seq_file to print to
* @pd: policy private data of interest
* @v: value to print
*
* Print @v to @sf for the device assocaited with @pd.
*/
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v)
{
int cpu;
struct blkio_group_stats_cpu *stats_cpu;
u64 val = 0, tval;
for_each_possible_cpu(cpu) {
unsigned int start;
stats_cpu = per_cpu_ptr(blkg->stats_cpu, cpu);
do {
start = u64_stats_fetch_begin(&stats_cpu->syncp);
if (type == BLKIO_STAT_CPU_SECTORS)
tval = stats_cpu->sectors;
else
tval = stats_cpu->stat_arr_cpu[type][sub_type];
} while(u64_stats_fetch_retry(&stats_cpu->syncp, start));
const char *dname = blkg_dev_name(pd->blkg);
val += tval;
}
if (!dname)
return 0;
return val;
seq_printf(sf, "%s %llu\n", dname, (unsigned long long)v);
return v;
}
EXPORT_SYMBOL_GPL(__blkg_prfill_u64);
static uint64_t blkio_get_stat_cpu(struct blkio_group *blkg,
struct cgroup_map_cb *cb, dev_t dev, enum stat_type_cpu type)
{
uint64_t disk_total, val;
char key_str[MAX_KEY_LEN];
enum stat_sub_type sub_type;
/**
* __blkg_prfill_rwstat - prfill helper for a blkg_rwstat
* @sf: seq_file to print to
* @pd: policy private data of interest
* @rwstat: rwstat to print
*
* Print @rwstat to @sf for the device assocaited with @pd.
*/
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
const struct blkg_rwstat *rwstat)
{
static const char *rwstr[] = {
[BLKG_RWSTAT_READ] = "Read",
[BLKG_RWSTAT_WRITE] = "Write",
[BLKG_RWSTAT_SYNC] = "Sync",
[BLKG_RWSTAT_ASYNC] = "Async",
};
const char *dname = blkg_dev_name(pd->blkg);
u64 v;
int i;
if (type == BLKIO_STAT_CPU_SECTORS) {
val = blkio_read_stat_cpu(blkg, type, 0);
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, val, cb, dev);
}
if (!dname)
return 0;
for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
sub_type++) {
blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
val = blkio_read_stat_cpu(blkg, type, sub_type);
cb->fill(cb, key_str, val);
}
for (i = 0; i < BLKG_RWSTAT_NR; i++)
seq_printf(sf, "%s %s %llu\n", dname, rwstr[i],
(unsigned long long)rwstat->cnt[i]);
disk_total = blkio_read_stat_cpu(blkg, type, BLKIO_STAT_READ) +
blkio_read_stat_cpu(blkg, type, BLKIO_STAT_WRITE);
v = rwstat->cnt[BLKG_RWSTAT_READ] + rwstat->cnt[BLKG_RWSTAT_WRITE];
seq_printf(sf, "%s Total %llu\n", dname, (unsigned long long)v);
return v;
}
blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
cb->fill(cb, key_str, disk_total);
return disk_total;
/**
* blkg_prfill_stat - prfill callback for blkg_stat
* @sf: seq_file to print to
* @pd: policy private data of interest
* @off: offset to the blkg_stat in @pd
*
* prfill callback for printing a blkg_stat.
*/
u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off)
{
return __blkg_prfill_u64(sf, pd, blkg_stat_read((void *)pd + off));
}
EXPORT_SYMBOL_GPL(blkg_prfill_stat);
/* This should be called with blkg->stats_lock held */
static uint64_t blkio_get_stat(struct blkio_group *blkg,
struct cgroup_map_cb *cb, dev_t dev, enum stat_type type)
/**
* blkg_prfill_rwstat - prfill callback for blkg_rwstat
* @sf: seq_file to print to
* @pd: policy private data of interest
* @off: offset to the blkg_rwstat in @pd
*
* prfill callback for printing a blkg_rwstat.
*/
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
uint64_t disk_total;
char key_str[MAX_KEY_LEN];
enum stat_sub_type sub_type;
if (type == BLKIO_STAT_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.time, cb, dev);
#ifdef CONFIG_DEBUG_BLK_CGROUP
if (type == BLKIO_STAT_UNACCOUNTED_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.unaccounted_time, cb, dev);
if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
uint64_t sum = blkg->stats.avg_queue_size_sum;
uint64_t samples = blkg->stats.avg_queue_size_samples;
if (samples)
do_div(sum, samples);
else
sum = 0;
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1, sum, cb, dev);
}
if (type == BLKIO_STAT_GROUP_WAIT_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.group_wait_time, cb, dev);
if (type == BLKIO_STAT_IDLE_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.idle_time, cb, dev);
if (type == BLKIO_STAT_EMPTY_TIME)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.empty_time, cb, dev);
if (type == BLKIO_STAT_DEQUEUE)
return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
blkg->stats.dequeue, cb, dev);
#endif
for (sub_type = BLKIO_STAT_READ; sub_type < BLKIO_STAT_TOTAL;
sub_type++) {
blkio_get_key_name(sub_type, dev, key_str, MAX_KEY_LEN, false);
cb->fill(cb, key_str, blkg->stats.stat_arr[type][sub_type]);
}
disk_total = blkg->stats.stat_arr[type][BLKIO_STAT_READ] +
blkg->stats.stat_arr[type][BLKIO_STAT_WRITE];
blkio_get_key_name(BLKIO_STAT_TOTAL, dev, key_str, MAX_KEY_LEN, false);
cb->fill(cb, key_str, disk_total);
return disk_total;
struct blkg_rwstat rwstat = blkg_rwstat_read((void *)pd + off);
return __blkg_prfill_rwstat(sf, pd, &rwstat);
}
EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
static int blkio_policy_parse_and_set(char *buf,
struct blkio_policy_node *newpn, enum blkio_policy_id plid, int fileid)
/**
* blkg_conf_prep - parse and prepare for per-blkg config update
* @blkcg: target block cgroup
* @pol: target policy
* @input: input string
* @ctx: blkg_conf_ctx to be filled
*
* Parse per-blkg config update from @input and initialize @ctx with the
* result. @ctx->blkg points to the blkg to be updated and @ctx->v the new
* value. This function returns with RCU read lock and queue lock held and
* must be paired with blkg_conf_finish().
*/
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
const char *input, struct blkg_conf_ctx *ctx)
__acquires(rcu) __acquires(disk->queue->queue_lock)
{
struct gendisk *disk = NULL;
char *s[4], *p, *major_s = NULL, *minor_s = NULL;
unsigned long major, minor;
int i = 0, ret = -EINVAL;
int part;
dev_t dev;
u64 temp;
memset(s, 0, sizeof(s));
while ((p = strsep(&buf, " ")) != NULL) {
if (!*p)
continue;
struct gendisk *disk;
struct blkcg_gq *blkg;
unsigned int major, minor;
unsigned long long v;
int part, ret;
s[i++] = p;
if (sscanf(input, "%u:%u %llu", &major, &minor, &v) != 3)
return -EINVAL;
/* Prevent from inputing too many things */
if (i == 3)
break;
}
disk = get_gendisk(MKDEV(major, minor), &part);
if (!disk || part)
return -EINVAL;
if (i != 2)
goto out;
rcu_read_lock();
spin_lock_irq(disk->queue->queue_lock);
p = strsep(&s[0], ":");
if (p != NULL)
major_s = p;
if (blkcg_policy_enabled(disk->queue, pol))
blkg = blkg_lookup_create(blkcg, disk->queue);
else
goto out;
blkg = ERR_PTR(-EINVAL);
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
rcu_read_unlock();
spin_unlock_irq(disk->queue->queue_lock);
put_disk(disk);
/*
* If queue was bypassing, we should retry. Do so after a
* short msleep(). It isn't strictly necessary but queue
* can be bypassing for some time and it's always nice to
* avoid busy looping.
*/
if (ret == -EBUSY) {
msleep(10);
ret = restart_syscall();
}
return ret;
}
ctx->disk = disk;
ctx->blkg = blkg;
ctx->v = v;
return 0;
}
EXPORT_SYMBOL_GPL(blkg_conf_prep);
minor_s = s[0];
if (!minor_s)
goto out;
/**
* blkg_conf_finish - finish up per-blkg config update
* @ctx: blkg_conf_ctx intiailized by blkg_conf_prep()
*
* Finish up after per-blkg config update. This function must be paired
* with blkg_conf_prep().
*/
void blkg_conf_finish(struct blkg_conf_ctx *ctx)
__releases(ctx->disk->queue->queue_lock) __releases(rcu)
{
spin_unlock_irq(ctx->disk->queue->queue_lock);
rcu_read_unlock();
put_disk(ctx->disk);
}
EXPORT_SYMBOL_GPL(blkg_conf_finish);
if (strict_strtoul(major_s, 10, &major))
goto out;
struct cftype blkcg_files[] = {
{
.name = "reset_stats",
.write_u64 = blkcg_reset_stats,
},
{ } /* terminate */
};
if (strict_strtoul(minor_s, 10, &minor))
goto out;
/**
* blkcg_pre_destroy - cgroup pre_destroy callback
* @cgroup: cgroup of interest
*
* This function is called when @cgroup is about to go away and responsible
* for shooting down all blkgs associated with @cgroup. blkgs should be
* removed while holding both q and blkcg locks. As blkcg lock is nested
* inside q lock, this function performs reverse double lock dancing.
*
* This is the blkcg counterpart of ioc_release_fn().
*/
static int blkcg_pre_destroy(struct cgroup *cgroup)
{
struct blkcg *blkcg = cgroup_to_blkcg(cgroup);
dev = MKDEV(major, minor);
spin_lock_irq(&blkcg->lock);
if (strict_strtoull(s[1], 10, &temp))
goto out;
while (!hlist_empty(&blkcg->blkg_list)) {
struct blkcg_gq *blkg = hlist_entry(blkcg->blkg_list.first,
struct blkcg_gq, blkcg_node);
struct request_queue *q = blkg->q;
/* For rule removal, do not check for device presence. */
if (temp) {
disk = get_gendisk(dev, &part);
if (!disk || part) {
ret = -ENODEV;
goto out;
if (spin_trylock(q->queue_lock)) {
blkg_destroy(blkg);
spin_unlock(q->queue_lock);
} else {
spin_unlock_irq(&blkcg->lock);
cpu_relax();
spin_lock_irq(&blkcg->lock);
}
}
newpn->dev = dev;
spin_unlock_irq(&blkcg->lock);
return 0;
}
switch (plid) {
case BLKIO_POLICY_PROP:
if ((temp < BLKIO_WEIGHT_MIN && temp > 0) ||
temp > BLKIO_WEIGHT_MAX)
goto out;
static void blkcg_destroy(struct cgroup *cgroup)
{
struct blkcg *blkcg = cgroup_to_blkcg(cgroup);
newpn->plid = plid;
newpn->fileid = fileid;
newpn->val.weight = temp;
break;
case BLKIO_POLICY_THROTL:
switch(fileid) {
case BLKIO_THROTL_read_bps_device:
case BLKIO_THROTL_write_bps_device:
newpn->plid = plid;
newpn->fileid = fileid;
newpn->val.bps = temp;
break;
case BLKIO_THROTL_read_iops_device:
case BLKIO_THROTL_write_iops_device:
if (temp > THROTL_IOPS_MAX)
goto out;
newpn->plid = plid;
newpn->fileid = fileid;
newpn->val.iops = (unsigned int)temp;
break;
}
break;
default:
BUG();
}
ret = 0;
out:
put_disk(disk);
return ret;
if (blkcg != &blkcg_root)
kfree(blkcg);
}
unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
dev_t dev)
static struct cgroup_subsys_state *blkcg_create(struct cgroup *cgroup)
{
struct blkio_policy_node *pn;
unsigned long flags;
unsigned int weight;
static atomic64_t id_seq = ATOMIC64_INIT(0);
struct blkcg *blkcg;
struct cgroup *parent = cgroup->parent;
spin_lock_irqsave(&blkcg->lock, flags);
if (!parent) {
blkcg = &blkcg_root;
goto done;
}
pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_PROP,
BLKIO_PROP_weight_device);
if (pn)
weight = pn->val.weight;
else
weight = blkcg->weight;
blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
if (!blkcg)
return ERR_PTR(-ENOMEM);
spin_unlock_irqrestore(&blkcg->lock, flags);
blkcg->cfq_weight = CFQ_WEIGHT_DEFAULT;
blkcg->id = atomic64_inc_return(&id_seq); /* root is 0, start from 1 */
done:
spin_lock_init(&blkcg->lock);
INIT_RADIX_TREE(&blkcg->blkg_tree, GFP_ATOMIC);
INIT_HLIST_HEAD(&blkcg->blkg_list);
return weight;
return &blkcg->css;
}
EXPORT_SYMBOL_GPL(blkcg_get_weight);
uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg, dev_t dev)
/**
* blkcg_init_queue - initialize blkcg part of request queue
* @q: request_queue to initialize
*
* Called from blk_alloc_queue_node(). Responsible for initializing blkcg
* part of new request_queue @q.
*
* RETURNS:
* 0 on success, -errno on failure.
*/
int blkcg_init_queue(struct request_queue *q)
{
struct blkio_policy_node *pn;
unsigned long flags;
uint64_t bps = -1;
spin_lock_irqsave(&blkcg->lock, flags);
pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
BLKIO_THROTL_read_bps_device);
if (pn)
bps = pn->val.bps;
spin_unlock_irqrestore(&blkcg->lock, flags);
return bps;
}
might_sleep();
uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg, dev_t dev)
{
struct blkio_policy_node *pn;
unsigned long flags;
uint64_t bps = -1;
spin_lock_irqsave(&blkcg->lock, flags);
pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
BLKIO_THROTL_write_bps_device);
if (pn)
bps = pn->val.bps;
spin_unlock_irqrestore(&blkcg->lock, flags);
return bps;
return blk_throtl_init(q);
}
unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg, dev_t dev)
/**
* blkcg_drain_queue - drain blkcg part of request_queue
* @q: request_queue to drain
*
* Called from blk_drain_queue(). Responsible for draining blkcg part.
*/
void blkcg_drain_queue(struct request_queue *q)
{
struct blkio_policy_node *pn;
unsigned long flags;
unsigned int iops = -1;
spin_lock_irqsave(&blkcg->lock, flags);
pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
BLKIO_THROTL_read_iops_device);
if (pn)
iops = pn->val.iops;
spin_unlock_irqrestore(&blkcg->lock, flags);
return iops;
lockdep_assert_held(q->queue_lock);
blk_throtl_drain(q);
}
unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg, dev_t dev)
/**
* blkcg_exit_queue - exit and release blkcg part of request_queue
* @q: request_queue being released
*
* Called from blk_release_queue(). Responsible for exiting blkcg part.
*/
void blkcg_exit_queue(struct request_queue *q)
{
struct blkio_policy_node *pn;
unsigned long flags;
unsigned int iops = -1;
spin_lock_irqsave(&blkcg->lock, flags);
pn = blkio_policy_search_node(blkcg, dev, BLKIO_POLICY_THROTL,
BLKIO_THROTL_write_iops_device);
if (pn)
iops = pn->val.iops;
spin_unlock_irqrestore(&blkcg->lock, flags);
return iops;
}
/* Checks whether user asked for deleting a policy rule */
static bool blkio_delete_rule_command(struct blkio_policy_node *pn)
{
switch(pn->plid) {
case BLKIO_POLICY_PROP:
if (pn->val.weight == 0)
return 1;
break;
case BLKIO_POLICY_THROTL:
switch(pn->fileid) {
case BLKIO_THROTL_read_bps_device:
case BLKIO_THROTL_write_bps_device:
if (pn->val.bps == 0)
return 1;
break;
case BLKIO_THROTL_read_iops_device:
case BLKIO_THROTL_write_iops_device:
if (pn->val.iops == 0)
return 1;
}
break;
default:
BUG();
}
return 0;
}
static void blkio_update_policy_rule(struct blkio_policy_node *oldpn,
struct blkio_policy_node *newpn)
{
switch(oldpn->plid) {
case BLKIO_POLICY_PROP:
oldpn->val.weight = newpn->val.weight;
break;
case BLKIO_POLICY_THROTL:
switch(newpn->fileid) {
case BLKIO_THROTL_read_bps_device:
case BLKIO_THROTL_write_bps_device:
oldpn->val.bps = newpn->val.bps;
break;
case BLKIO_THROTL_read_iops_device:
case BLKIO_THROTL_write_iops_device:
oldpn->val.iops = newpn->val.iops;
}
break;
default:
BUG();
}
spin_lock_irq(q->queue_lock);
blkg_destroy_all(q);
spin_unlock_irq(q->queue_lock);
blk_throtl_exit(q);
}
/*
* Some rules/values in blkg have changed. Propagate those to respective
* policies.
*/
static void blkio_update_blkg_policy(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, struct blkio_policy_node *pn)
{
unsigned int weight, iops;
u64 bps;
switch(pn->plid) {
case BLKIO_POLICY_PROP:
weight = pn->val.weight ? pn->val.weight :
blkcg->weight;
blkio_update_group_weight(blkg, weight);
break;
case BLKIO_POLICY_THROTL:
switch(pn->fileid) {
case BLKIO_THROTL_read_bps_device:
case BLKIO_THROTL_write_bps_device:
bps = pn->val.bps ? pn->val.bps : (-1);
blkio_update_group_bps(blkg, bps, pn->fileid);
break;
case BLKIO_THROTL_read_iops_device:
case BLKIO_THROTL_write_iops_device:
iops = pn->val.iops ? pn->val.iops : (-1);
blkio_update_group_iops(blkg, iops, pn->fileid);
break;
}
break;
default:
BUG();
}
}
/*
* A policy node rule has been updated. Propagate this update to all the
* block groups which might be affected by this update.
* We cannot support shared io contexts, as we have no mean to support
* two tasks with the same ioc in two different groups without major rework
* of the main cic data structures. For now we allow a task to change
* its cgroup only if it's the only owner of its ioc.
*/
static void blkio_update_policy_node_blkg(struct blkio_cgroup *blkcg,
struct blkio_policy_node *pn)
{
struct blkio_group *blkg;
struct hlist_node *n;
spin_lock(&blkio_list_lock);
spin_lock_irq(&blkcg->lock);
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
if (pn->dev != blkg->dev || pn->plid != blkg->plid)
continue;
blkio_update_blkg_policy(blkcg, blkg, pn);
}
spin_unlock_irq(&blkcg->lock);
spin_unlock(&blkio_list_lock);
}
static int blkiocg_file_write(struct cgroup *cgrp, struct cftype *cft,
const char *buffer)
static int blkcg_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
struct task_struct *task;
struct io_context *ioc;
int ret = 0;
char *buf;
struct blkio_policy_node *newpn, *pn;
struct blkio_cgroup *blkcg;
int keep_newpn = 0;
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
int fileid = BLKIOFILE_ATTR(cft->private);
buf = kstrdup(buffer, GFP_KERNEL);
if (!buf)
return -ENOMEM;
newpn = kzalloc(sizeof(*newpn), GFP_KERNEL);
if (!newpn) {
ret = -ENOMEM;
goto free_buf;
}
ret = blkio_policy_parse_and_set(buf, newpn, plid, fileid);
/* task_lock() is needed to avoid races with exit_io_context() */
cgroup_taskset_for_each(task, cgrp, tset) {
task_lock(task);
ioc = task->io_context;
if (ioc && atomic_read(&ioc->nr_tasks) > 1)
ret = -EINVAL;
task_unlock(task);
if (ret)
goto free_newpn;
blkcg = cgroup_to_blkio_cgroup(cgrp);
spin_lock_irq(&blkcg->lock);
pn = blkio_policy_search_node(blkcg, newpn->dev, plid, fileid);
if (!pn) {
if (!blkio_delete_rule_command(newpn)) {
blkio_policy_insert_node(blkcg, newpn);
keep_newpn = 1;
}
spin_unlock_irq(&blkcg->lock);
goto update_io_group;
}
if (blkio_delete_rule_command(newpn)) {
blkio_policy_delete_node(pn);
kfree(pn);
spin_unlock_irq(&blkcg->lock);
goto update_io_group;
}
spin_unlock_irq(&blkcg->lock);
blkio_update_policy_rule(pn, newpn);
update_io_group:
blkio_update_policy_node_blkg(blkcg, newpn);
free_newpn:
if (!keep_newpn)
kfree(newpn);
free_buf:
kfree(buf);
return ret;
}
static void
blkio_print_policy_node(struct seq_file *m, struct blkio_policy_node *pn)
{
switch(pn->plid) {
case BLKIO_POLICY_PROP:
if (pn->fileid == BLKIO_PROP_weight_device)
seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
MINOR(pn->dev), pn->val.weight);
break;
case BLKIO_POLICY_THROTL:
switch(pn->fileid) {
case BLKIO_THROTL_read_bps_device:
case BLKIO_THROTL_write_bps_device:
seq_printf(m, "%u:%u\t%llu\n", MAJOR(pn->dev),
MINOR(pn->dev), pn->val.bps);
break;
case BLKIO_THROTL_read_iops_device:
case BLKIO_THROTL_write_iops_device:
seq_printf(m, "%u:%u\t%u\n", MAJOR(pn->dev),
MINOR(pn->dev), pn->val.iops);
break;
}
break;
default:
BUG();
}
return ret;
}
/* cgroup files which read their data from policy nodes end up here */
static void blkio_read_policy_node_files(struct cftype *cft,
struct blkio_cgroup *blkcg, struct seq_file *m)
{
struct blkio_policy_node *pn;
if (!list_empty(&blkcg->policy_list)) {
spin_lock_irq(&blkcg->lock);
list_for_each_entry(pn, &blkcg->policy_list, node) {
if (!pn_matches_cftype(cft, pn))
continue;
blkio_print_policy_node(m, pn);
}
spin_unlock_irq(&blkcg->lock);
}
}
struct cgroup_subsys blkio_subsys = {
.name = "blkio",
.create = blkcg_create,
.can_attach = blkcg_can_attach,
.pre_destroy = blkcg_pre_destroy,
.destroy = blkcg_destroy,
.subsys_id = blkio_subsys_id,
.base_cftypes = blkcg_files,
.module = THIS_MODULE,
};
EXPORT_SYMBOL_GPL(blkio_subsys);
static int blkiocg_file_read(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *m)
/**
* blkcg_activate_policy - activate a blkcg policy on a request_queue
* @q: request_queue of interest
* @pol: blkcg policy to activate
*
* Activate @pol on @q. Requires %GFP_KERNEL context. @q goes through
* bypass mode to populate its blkgs with policy_data for @pol.
*
* Activation happens with @q bypassed, so nobody would be accessing blkgs
* from IO path. Update of each blkg is protected by both queue and blkcg
* locks so that holding either lock and testing blkcg_policy_enabled() is
* always enough for dereferencing policy data.
*
* The caller is responsible for synchronizing [de]activations and policy
* [un]registerations. Returns 0 on success, -errno on failure.
*/
int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol)
{
struct blkio_cgroup *blkcg;
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
int name = BLKIOFILE_ATTR(cft->private);
LIST_HEAD(pds);
struct blkcg_gq *blkg;
struct blkg_policy_data *pd, *n;
int cnt = 0, ret;
blkcg = cgroup_to_blkio_cgroup(cgrp);
switch(plid) {
case BLKIO_POLICY_PROP:
switch(name) {
case BLKIO_PROP_weight_device:
blkio_read_policy_node_files(cft, blkcg, m);
return 0;
default:
BUG();
}
break;
case BLKIO_POLICY_THROTL:
switch(name){
case BLKIO_THROTL_read_bps_device:
case BLKIO_THROTL_write_bps_device:
case BLKIO_THROTL_read_iops_device:
case BLKIO_THROTL_write_iops_device:
blkio_read_policy_node_files(cft, blkcg, m);
if (blkcg_policy_enabled(q, pol))
return 0;
default:
BUG();
}
break;
default:
BUG();
}
return 0;
}
blk_queue_bypass_start(q);
static int blkio_read_blkg_stats(struct blkio_cgroup *blkcg,
struct cftype *cft, struct cgroup_map_cb *cb,
enum stat_type type, bool show_total, bool pcpu)
{
struct blkio_group *blkg;
struct hlist_node *n;
uint64_t cgroup_total = 0;
/* make sure the root blkg exists and count the existing blkgs */
spin_lock_irq(q->queue_lock);
rcu_read_lock();
hlist_for_each_entry_rcu(blkg, n, &blkcg->blkg_list, blkcg_node) {
if (blkg->dev) {
if (!cftype_blkg_same_policy(cft, blkg))
continue;
if (pcpu)
cgroup_total += blkio_get_stat_cpu(blkg, cb,
blkg->dev, type);
else {
spin_lock_irq(&blkg->stats_lock);
cgroup_total += blkio_get_stat(blkg, cb,
blkg->dev, type);
spin_unlock_irq(&blkg->stats_lock);
}
}
}
if (show_total)
cb->fill(cb, "Total", cgroup_total);
blkg = __blkg_lookup_create(&blkcg_root, q);
rcu_read_unlock();
return 0;
}
/* All map kind of cgroup file get serviced by this function */
static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
struct cgroup_map_cb *cb)
{
struct blkio_cgroup *blkcg;
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
int name = BLKIOFILE_ATTR(cft->private);
blkcg = cgroup_to_blkio_cgroup(cgrp);
switch(plid) {
case BLKIO_POLICY_PROP:
switch(name) {
case BLKIO_PROP_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_TIME, 0, 0);
case BLKIO_PROP_sectors:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_CPU_SECTORS, 0, 1);
case BLKIO_PROP_io_service_bytes:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
case BLKIO_PROP_io_serviced:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_CPU_SERVICED, 1, 1);
case BLKIO_PROP_io_service_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_SERVICE_TIME, 1, 0);
case BLKIO_PROP_io_wait_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_WAIT_TIME, 1, 0);
case BLKIO_PROP_io_merged:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_CPU_MERGED, 1, 1);
case BLKIO_PROP_io_queued:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_QUEUED, 1, 0);
#ifdef CONFIG_DEBUG_BLK_CGROUP
case BLKIO_PROP_unaccounted_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_UNACCOUNTED_TIME, 0, 0);
case BLKIO_PROP_dequeue:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_DEQUEUE, 0, 0);
case BLKIO_PROP_avg_queue_size:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_AVG_QUEUE_SIZE, 0, 0);
case BLKIO_PROP_group_wait_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_GROUP_WAIT_TIME, 0, 0);
case BLKIO_PROP_idle_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_IDLE_TIME, 0, 0);
case BLKIO_PROP_empty_time:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_EMPTY_TIME, 0, 0);
#endif
default:
BUG();
}
break;
case BLKIO_POLICY_THROTL:
switch(name){
case BLKIO_THROTL_io_service_bytes:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_CPU_SERVICE_BYTES, 1, 1);
case BLKIO_THROTL_io_serviced:
return blkio_read_blkg_stats(blkcg, cft, cb,
BLKIO_STAT_CPU_SERVICED, 1, 1);
default:
BUG();
}
break;
default:
BUG();
if (IS_ERR(blkg)) {
ret = PTR_ERR(blkg);
goto out_unlock;
}
q->root_blkg = blkg;
return 0;
}
list_for_each_entry(blkg, &q->blkg_list, q_node)
cnt++;
static int blkio_weight_write(struct blkio_cgroup *blkcg, u64 val)
{
struct blkio_group *blkg;
struct hlist_node *n;
struct blkio_policy_node *pn;
if (val < BLKIO_WEIGHT_MIN || val > BLKIO_WEIGHT_MAX)
return -EINVAL;
spin_lock(&blkio_list_lock);
spin_lock_irq(&blkcg->lock);
blkcg->weight = (unsigned int)val;
spin_unlock_irq(q->queue_lock);
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
pn = blkio_policy_search_node(blkcg, blkg->dev,
BLKIO_POLICY_PROP, BLKIO_PROP_weight_device);
if (pn)
continue;
blkio_update_group_weight(blkg, blkcg->weight);
/* allocate policy_data for all existing blkgs */
while (cnt--) {
pd = kzalloc_node(pol->pd_size, GFP_KERNEL, q->node);
if (!pd) {
ret = -ENOMEM;
goto out_free;
}
list_add_tail(&pd->alloc_node, &pds);
}
spin_unlock_irq(&blkcg->lock);
spin_unlock(&blkio_list_lock);
return 0;
}
static u64 blkiocg_file_read_u64 (struct cgroup *cgrp, struct cftype *cft) {
struct blkio_cgroup *blkcg;
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
int name = BLKIOFILE_ATTR(cft->private);
blkcg = cgroup_to_blkio_cgroup(cgrp);
/*
* Install the allocated pds. With @q bypassing, no new blkg
* should have been created while the queue lock was dropped.
*/
spin_lock_irq(q->queue_lock);
switch(plid) {
case BLKIO_POLICY_PROP:
switch(name) {
case BLKIO_PROP_weight:
return (u64)blkcg->weight;
}
break;
default:
BUG();
list_for_each_entry(blkg, &q->blkg_list, q_node) {
if (WARN_ON(list_empty(&pds))) {
/* umm... this shouldn't happen, just abort */
ret = -ENOMEM;
goto out_unlock;
}
return 0;
}
pd = list_first_entry(&pds, struct blkg_policy_data, alloc_node);
list_del_init(&pd->alloc_node);
static int
blkiocg_file_write_u64(struct cgroup *cgrp, struct cftype *cft, u64 val)
{
struct blkio_cgroup *blkcg;
enum blkio_policy_id plid = BLKIOFILE_POLICY(cft->private);
int name = BLKIOFILE_ATTR(cft->private);
/* grab blkcg lock too while installing @pd on @blkg */
spin_lock(&blkg->blkcg->lock);
blkcg = cgroup_to_blkio_cgroup(cgrp);
blkg->pd[pol->plid] = pd;
pd->blkg = blkg;
pol->pd_init_fn(blkg);
switch(plid) {
case BLKIO_POLICY_PROP:
switch(name) {
case BLKIO_PROP_weight:
return blkio_weight_write(blkcg, val);
}
break;
default:
BUG();
spin_unlock(&blkg->blkcg->lock);
}
return 0;
__set_bit(pol->plid, q->blkcg_pols);
ret = 0;
out_unlock:
spin_unlock_irq(q->queue_lock);
out_free:
blk_queue_bypass_end(q);
list_for_each_entry_safe(pd, n, &pds, alloc_node)
kfree(pd);
return ret;
}
EXPORT_SYMBOL_GPL(blkcg_activate_policy);
struct cftype blkio_files[] = {
{
.name = "weight_device",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_weight_device),
.read_seq_string = blkiocg_file_read,
.write_string = blkiocg_file_write,
.max_write_len = 256,
},
{
.name = "weight",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_weight),
.read_u64 = blkiocg_file_read_u64,
.write_u64 = blkiocg_file_write_u64,
},
{
.name = "time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_time),
.read_map = blkiocg_file_read_map,
},
{
.name = "sectors",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_sectors),
.read_map = blkiocg_file_read_map,
},
{
.name = "io_service_bytes",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_service_bytes),
.read_map = blkiocg_file_read_map,
},
{
.name = "io_serviced",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_serviced),
.read_map = blkiocg_file_read_map,
},
{
.name = "io_service_time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_service_time),
.read_map = blkiocg_file_read_map,
},
{
.name = "io_wait_time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_wait_time),
.read_map = blkiocg_file_read_map,
},
{
.name = "io_merged",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_merged),
.read_map = blkiocg_file_read_map,
},
{
.name = "io_queued",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_io_queued),
.read_map = blkiocg_file_read_map,
},
{
.name = "reset_stats",
.write_u64 = blkiocg_reset_stats,
},
#ifdef CONFIG_BLK_DEV_THROTTLING
{
.name = "throttle.read_bps_device",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
BLKIO_THROTL_read_bps_device),
.read_seq_string = blkiocg_file_read,
.write_string = blkiocg_file_write,
.max_write_len = 256,
},
{
.name = "throttle.write_bps_device",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
BLKIO_THROTL_write_bps_device),
.read_seq_string = blkiocg_file_read,
.write_string = blkiocg_file_write,
.max_write_len = 256,
},
{
.name = "throttle.read_iops_device",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
BLKIO_THROTL_read_iops_device),
.read_seq_string = blkiocg_file_read,
.write_string = blkiocg_file_write,
.max_write_len = 256,
},
{
.name = "throttle.write_iops_device",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
BLKIO_THROTL_write_iops_device),
.read_seq_string = blkiocg_file_read,
.write_string = blkiocg_file_write,
.max_write_len = 256,
},
{
.name = "throttle.io_service_bytes",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
BLKIO_THROTL_io_service_bytes),
.read_map = blkiocg_file_read_map,
},
{
.name = "throttle.io_serviced",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_THROTL,
BLKIO_THROTL_io_serviced),
.read_map = blkiocg_file_read_map,
},
#endif /* CONFIG_BLK_DEV_THROTTLING */
#ifdef CONFIG_DEBUG_BLK_CGROUP
{
.name = "avg_queue_size",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_avg_queue_size),
.read_map = blkiocg_file_read_map,
},
{
.name = "group_wait_time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_group_wait_time),
.read_map = blkiocg_file_read_map,
},
{
.name = "idle_time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_idle_time),
.read_map = blkiocg_file_read_map,
},
{
.name = "empty_time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_empty_time),
.read_map = blkiocg_file_read_map,
},
{
.name = "dequeue",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_dequeue),
.read_map = blkiocg_file_read_map,
},
{
.name = "unaccounted_time",
.private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
BLKIO_PROP_unaccounted_time),
.read_map = blkiocg_file_read_map,
},
#endif
{ } /* terminate */
};
static void blkiocg_destroy(struct cgroup *cgroup)
/**
* blkcg_deactivate_policy - deactivate a blkcg policy on a request_queue
* @q: request_queue of interest
* @pol: blkcg policy to deactivate
*
* Deactivate @pol on @q. Follows the same synchronization rules as
* blkcg_activate_policy().
*/
void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol)
{
struct blkio_cgroup *blkcg = cgroup_to_blkio_cgroup(cgroup);
unsigned long flags;
struct blkio_group *blkg;
void *key;
struct blkio_policy_type *blkiop;
struct blkio_policy_node *pn, *pntmp;
struct blkcg_gq *blkg;
rcu_read_lock();
do {
spin_lock_irqsave(&blkcg->lock, flags);
if (hlist_empty(&blkcg->blkg_list)) {
spin_unlock_irqrestore(&blkcg->lock, flags);
break;
}
if (!blkcg_policy_enabled(q, pol))
return;
blkg = hlist_entry(blkcg->blkg_list.first, struct blkio_group,
blkcg_node);
key = rcu_dereference(blkg->key);
__blkiocg_del_blkio_group(blkg);
blk_queue_bypass_start(q);
spin_lock_irq(q->queue_lock);
spin_unlock_irqrestore(&blkcg->lock, flags);
__clear_bit(pol->plid, q->blkcg_pols);
/*
* This blkio_group is being unlinked as associated cgroup is
* going away. Let all the IO controlling policies know about
* this event.
*/
spin_lock(&blkio_list_lock);
list_for_each_entry(blkiop, &blkio_list, list) {
if (blkiop->plid != blkg->plid)
continue;
blkiop->ops.blkio_unlink_group_fn(key, blkg);
}
spin_unlock(&blkio_list_lock);
} while (1);
/* if no policy is left, no need for blkgs - shoot them down */
if (bitmap_empty(q->blkcg_pols, BLKCG_MAX_POLS))
blkg_destroy_all(q);
list_for_each_entry_safe(pn, pntmp, &blkcg->policy_list, node) {
blkio_policy_delete_node(pn);
kfree(pn);
}
list_for_each_entry(blkg, &q->blkg_list, q_node) {
/* grab blkcg lock too while removing @pd from @blkg */
spin_lock(&blkg->blkcg->lock);
free_css_id(&blkio_subsys, &blkcg->css);
rcu_read_unlock();
if (blkcg != &blkio_root_cgroup)
kfree(blkcg);
}
if (pol->pd_exit_fn)
pol->pd_exit_fn(blkg);
static struct cgroup_subsys_state *blkiocg_create(struct cgroup *cgroup)
{
struct blkio_cgroup *blkcg;
struct cgroup *parent = cgroup->parent;
kfree(blkg->pd[pol->plid]);
blkg->pd[pol->plid] = NULL;
if (!parent) {
blkcg = &blkio_root_cgroup;
goto done;
spin_unlock(&blkg->blkcg->lock);
}
blkcg = kzalloc(sizeof(*blkcg), GFP_KERNEL);
if (!blkcg)
return ERR_PTR(-ENOMEM);
blkcg->weight = BLKIO_WEIGHT_DEFAULT;
done:
spin_lock_init(&blkcg->lock);
INIT_HLIST_HEAD(&blkcg->blkg_list);
INIT_LIST_HEAD(&blkcg->policy_list);
return &blkcg->css;
spin_unlock_irq(q->queue_lock);
blk_queue_bypass_end(q);
}
EXPORT_SYMBOL_GPL(blkcg_deactivate_policy);
/*
* We cannot support shared io contexts, as we have no mean to support
* two tasks with the same ioc in two different groups without major rework
* of the main cic data structures. For now we allow a task to change
* its cgroup only if it's the only owner of its ioc.
/**
* blkcg_policy_register - register a blkcg policy
* @pol: blkcg policy to register
*
* Register @pol with blkcg core. Might sleep and @pol may be modified on
* successful registration. Returns 0 on success and -errno on failure.
*/
static int blkiocg_can_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
int blkcg_policy_register(struct blkcg_policy *pol)
{
struct task_struct *task;
struct io_context *ioc;
int ret = 0;
int i, ret;
/* task_lock() is needed to avoid races with exit_io_context() */
cgroup_taskset_for_each(task, cgrp, tset) {
task_lock(task);
ioc = task->io_context;
if (ioc && atomic_read(&ioc->nr_tasks) > 1)
ret = -EINVAL;
task_unlock(task);
if (ret)
break;
}
return ret;
}
if (WARN_ON(pol->pd_size < sizeof(struct blkg_policy_data)))
return -EINVAL;
static void blkiocg_attach(struct cgroup *cgrp, struct cgroup_taskset *tset)
{
struct task_struct *task;
struct io_context *ioc;
mutex_lock(&blkcg_pol_mutex);
cgroup_taskset_for_each(task, cgrp, tset) {
/* we don't lose anything even if ioc allocation fails */
ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
if (ioc) {
ioc_cgroup_changed(ioc);
put_io_context(ioc);
}
}
}
/* find an empty slot */
ret = -ENOSPC;
for (i = 0; i < BLKCG_MAX_POLS; i++)
if (!blkcg_policy[i])
break;
if (i >= BLKCG_MAX_POLS)
goto out_unlock;
struct cgroup_subsys blkio_subsys = {
.name = "blkio",
.create = blkiocg_create,
.can_attach = blkiocg_can_attach,
.attach = blkiocg_attach,
.destroy = blkiocg_destroy,
#ifdef CONFIG_BLK_CGROUP
/* note: blkio_subsys_id is otherwise defined in blk-cgroup.h */
.subsys_id = blkio_subsys_id,
#endif
.base_cftypes = blkio_files,
.use_id = 1,
.module = THIS_MODULE,
};
EXPORT_SYMBOL_GPL(blkio_subsys);
/* register and update blkgs */
pol->plid = i;
blkcg_policy[i] = pol;
void blkio_policy_register(struct blkio_policy_type *blkiop)
{
spin_lock(&blkio_list_lock);
list_add_tail(&blkiop->list, &blkio_list);
spin_unlock(&blkio_list_lock);
/* everything is in place, add intf files for the new policy */
if (pol->cftypes)
WARN_ON(cgroup_add_cftypes(&blkio_subsys, pol->cftypes));
ret = 0;
out_unlock:
mutex_unlock(&blkcg_pol_mutex);
return ret;
}
EXPORT_SYMBOL_GPL(blkio_policy_register);
EXPORT_SYMBOL_GPL(blkcg_policy_register);
void blkio_policy_unregister(struct blkio_policy_type *blkiop)
/**
* blkcg_policy_unregister - unregister a blkcg policy
* @pol: blkcg policy to unregister
*
* Undo blkcg_policy_register(@pol). Might sleep.
*/
void blkcg_policy_unregister(struct blkcg_policy *pol)
{
spin_lock(&blkio_list_lock);
list_del_init(&blkiop->list);
spin_unlock(&blkio_list_lock);
}
EXPORT_SYMBOL_GPL(blkio_policy_unregister);
mutex_lock(&blkcg_pol_mutex);
static int __init init_cgroup_blkio(void)
{
return cgroup_load_subsys(&blkio_subsys);
}
if (WARN_ON(blkcg_policy[pol->plid] != pol))
goto out_unlock;
static void __exit exit_cgroup_blkio(void)
{
cgroup_unload_subsys(&blkio_subsys);
}
/* kill the intf files first */
if (pol->cftypes)
cgroup_rm_cftypes(&blkio_subsys, pol->cftypes);
module_init(init_cgroup_blkio);
module_exit(exit_cgroup_blkio);
MODULE_LICENSE("GPL");
/* unregister and update blkgs */
blkcg_policy[pol->plid] = NULL;
out_unlock:
mutex_unlock(&blkcg_pol_mutex);
}
EXPORT_SYMBOL_GPL(blkcg_policy_unregister);
block/blk-cgroup.h
View file @ 0d167518
......@@ -15,350 +15,371 @@
#include <linux/cgroup.h>
#include <linux/u64_stats_sync.h>
enum blkio_policy_id {
BLKIO_POLICY_PROP = 0, /* Proportional Bandwidth division */
BLKIO_POLICY_THROTL, /* Throttling */
};
#include <linux/seq_file.h>
#include <linux/radix-tree.h>
/* Max limits for throttle policy */
#define THROTL_IOPS_MAX UINT_MAX
#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
#ifndef CONFIG_BLK_CGROUP
/* When blk-cgroup is a module, its subsys_id isn't a compile-time constant */
extern struct cgroup_subsys blkio_subsys;
#define blkio_subsys_id blkio_subsys.subsys_id
#endif
enum stat_type {
/* Total time spent (in ns) between request dispatch to the driver and
* request completion for IOs doen by this cgroup. This may not be
* accurate when NCQ is turned on. */
BLKIO_STAT_SERVICE_TIME = 0,
/* Total time spent waiting in scheduler queue in ns */
BLKIO_STAT_WAIT_TIME,
/* Number of IOs queued up */
BLKIO_STAT_QUEUED,
/* All the single valued stats go below this */
BLKIO_STAT_TIME,
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Time not charged to this cgroup */
BLKIO_STAT_UNACCOUNTED_TIME,
BLKIO_STAT_AVG_QUEUE_SIZE,
BLKIO_STAT_IDLE_TIME,
BLKIO_STAT_EMPTY_TIME,
BLKIO_STAT_GROUP_WAIT_TIME,
BLKIO_STAT_DEQUEUE
#endif
};
/* Per cpu stats */
enum stat_type_cpu {
BLKIO_STAT_CPU_SECTORS,
/* Total bytes transferred */
BLKIO_STAT_CPU_SERVICE_BYTES,
/* Total IOs serviced, post merge */
BLKIO_STAT_CPU_SERVICED,
/* Number of IOs merged */
BLKIO_STAT_CPU_MERGED,
BLKIO_STAT_CPU_NR
};
/* CFQ specific, out here for blkcg->cfq_weight */
#define CFQ_WEIGHT_MIN 10
#define CFQ_WEIGHT_MAX 1000
#define CFQ_WEIGHT_DEFAULT 500
enum stat_sub_type {
BLKIO_STAT_READ = 0,
BLKIO_STAT_WRITE,
BLKIO_STAT_SYNC,
BLKIO_STAT_ASYNC,
BLKIO_STAT_TOTAL
};
#ifdef CONFIG_BLK_CGROUP
/* blkg state flags */
enum blkg_state_flags {
BLKG_waiting = 0,
BLKG_idling,
BLKG_empty,
};
enum blkg_rwstat_type {
BLKG_RWSTAT_READ,
BLKG_RWSTAT_WRITE,
BLKG_RWSTAT_SYNC,
BLKG_RWSTAT_ASYNC,
/* cgroup files owned by proportional weight policy */
enum blkcg_file_name_prop {
BLKIO_PROP_weight = 1,
BLKIO_PROP_weight_device,
BLKIO_PROP_io_service_bytes,
BLKIO_PROP_io_serviced,
BLKIO_PROP_time,
BLKIO_PROP_sectors,
BLKIO_PROP_unaccounted_time,
BLKIO_PROP_io_service_time,
BLKIO_PROP_io_wait_time,
BLKIO_PROP_io_merged,
BLKIO_PROP_io_queued,
BLKIO_PROP_avg_queue_size,
BLKIO_PROP_group_wait_time,
BLKIO_PROP_idle_time,
BLKIO_PROP_empty_time,
BLKIO_PROP_dequeue,
BLKG_RWSTAT_NR,
BLKG_RWSTAT_TOTAL = BLKG_RWSTAT_NR,
};
/* cgroup files owned by throttle policy */
enum blkcg_file_name_throtl {
BLKIO_THROTL_read_bps_device,
BLKIO_THROTL_write_bps_device,
BLKIO_THROTL_read_iops_device,
BLKIO_THROTL_write_iops_device,
BLKIO_THROTL_io_service_bytes,
BLKIO_THROTL_io_serviced,
};
struct blkcg_gq;
struct blkio_cgroup {
struct blkcg {
struct cgroup_subsys_state css;
unsigned int weight;
spinlock_t lock;
struct radix_tree_root blkg_tree;
struct blkcg_gq *blkg_hint;
struct hlist_head blkg_list;
struct list_head policy_list; /* list of blkio_policy_node */
};
struct blkio_group_stats {
/* total disk time and nr sectors dispatched by this group */
uint64_t time;
uint64_t stat_arr[BLKIO_STAT_QUEUED + 1][BLKIO_STAT_TOTAL];
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* Time not charged to this cgroup */
uint64_t unaccounted_time;
/* Sum of number of IOs queued across all samples */
uint64_t avg_queue_size_sum;
/* Count of samples taken for average */
uint64_t avg_queue_size_samples;
/* How many times this group has been removed from service tree */
unsigned long dequeue;
/* Total time spent waiting for it to be assigned a timeslice. */
uint64_t group_wait_time;
uint64_t start_group_wait_time;
/* Time spent idling for this blkio_group */
uint64_t idle_time;
uint64_t start_idle_time;
/*
* Total time when we have requests queued and do not contain the
* current active queue.
*/
uint64_t empty_time;
uint64_t start_empty_time;
uint16_t flags;
#endif
/* for policies to test whether associated blkcg has changed */
uint64_t id;
/* TODO: per-policy storage in blkcg */
unsigned int cfq_weight; /* belongs to cfq */
};
/* Per cpu blkio group stats */
struct blkio_group_stats_cpu {
uint64_t sectors;
uint64_t stat_arr_cpu[BLKIO_STAT_CPU_NR][BLKIO_STAT_TOTAL];
struct blkg_stat {
struct u64_stats_sync syncp;
uint64_t cnt;
};
struct blkio_group {
/* An rcu protected unique identifier for the group */
void *key;
struct hlist_node blkcg_node;
unsigned short blkcg_id;
/* Store cgroup path */
char path[128];
/* The device MKDEV(major, minor), this group has been created for */
dev_t dev;
/* policy which owns this blk group */
enum blkio_policy_id plid;
/* Need to serialize the stats in the case of reset/update */
spinlock_t stats_lock;
struct blkio_group_stats stats;
/* Per cpu stats pointer */
struct blkio_group_stats_cpu __percpu *stats_cpu;
struct blkg_rwstat {
struct u64_stats_sync syncp;
uint64_t cnt[BLKG_RWSTAT_NR];
};
struct blkio_policy_node {
struct list_head node;
dev_t dev;
/* This node belongs to max bw policy or porportional weight policy */
enum blkio_policy_id plid;
/* cgroup file to which this rule belongs to */
int fileid;
union {
unsigned int weight;
/*
* Rate read/write in terms of bytes per second
* Whether this rate represents read or write is determined
* by file type "fileid".
/*
* A blkcg_gq (blkg) is association between a block cgroup (blkcg) and a
* request_queue (q). This is used by blkcg policies which need to track
* information per blkcg - q pair.
*
* There can be multiple active blkcg policies and each has its private
* data on each blkg, the size of which is determined by
* blkcg_policy->pd_size. blkcg core allocates and frees such areas
* together with blkg and invokes pd_init/exit_fn() methods.
*
* Such private data must embed struct blkg_policy_data (pd) at the
* beginning and pd_size can't be smaller than pd.
*/
u64 bps;
unsigned int iops;
} val;
struct blkg_policy_data {
/* the blkg this per-policy data belongs to */
struct blkcg_gq *blkg;
/* used during policy activation */
struct list_head alloc_node;
};
extern unsigned int blkcg_get_weight(struct blkio_cgroup *blkcg,
dev_t dev);
extern uint64_t blkcg_get_read_bps(struct blkio_cgroup *blkcg,
dev_t dev);
extern uint64_t blkcg_get_write_bps(struct blkio_cgroup *blkcg,
dev_t dev);
extern unsigned int blkcg_get_read_iops(struct blkio_cgroup *blkcg,
dev_t dev);
extern unsigned int blkcg_get_write_iops(struct blkio_cgroup *blkcg,
dev_t dev);
typedef void (blkio_unlink_group_fn) (void *key, struct blkio_group *blkg);
typedef void (blkio_update_group_weight_fn) (void *key,
struct blkio_group *blkg, unsigned int weight);
typedef void (blkio_update_group_read_bps_fn) (void * key,
struct blkio_group *blkg, u64 read_bps);
typedef void (blkio_update_group_write_bps_fn) (void *key,
struct blkio_group *blkg, u64 write_bps);
typedef void (blkio_update_group_read_iops_fn) (void *key,
struct blkio_group *blkg, unsigned int read_iops);
typedef void (blkio_update_group_write_iops_fn) (void *key,
struct blkio_group *blkg, unsigned int write_iops);
struct blkio_policy_ops {
blkio_unlink_group_fn *blkio_unlink_group_fn;
blkio_update_group_weight_fn *blkio_update_group_weight_fn;
blkio_update_group_read_bps_fn *blkio_update_group_read_bps_fn;
blkio_update_group_write_bps_fn *blkio_update_group_write_bps_fn;
blkio_update_group_read_iops_fn *blkio_update_group_read_iops_fn;
blkio_update_group_write_iops_fn *blkio_update_group_write_iops_fn;
/* association between a blk cgroup and a request queue */
struct blkcg_gq {
/* Pointer to the associated request_queue */
struct request_queue *q;
struct list_head q_node;
struct hlist_node blkcg_node;
struct blkcg *blkcg;
/* reference count */
int refcnt;
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
};
struct blkio_policy_type {
struct list_head list;
struct blkio_policy_ops ops;
enum blkio_policy_id plid;
typedef void (blkcg_pol_init_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_exit_pd_fn)(struct blkcg_gq *blkg);
typedef void (blkcg_pol_reset_pd_stats_fn)(struct blkcg_gq *blkg);
struct blkcg_policy {
int plid;
/* policy specific private data size */
size_t pd_size;
/* cgroup files for the policy */
struct cftype *cftypes;
/* operations */
blkcg_pol_init_pd_fn *pd_init_fn;
blkcg_pol_exit_pd_fn *pd_exit_fn;
blkcg_pol_reset_pd_stats_fn *pd_reset_stats_fn;
};
extern struct blkcg blkcg_root;
struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup);
struct blkcg *bio_blkcg(struct bio *bio);
struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, struct request_queue *q);
struct blkcg_gq *blkg_lookup_create(struct blkcg *blkcg,
struct request_queue *q);
int blkcg_init_queue(struct request_queue *q);
void blkcg_drain_queue(struct request_queue *q);
void blkcg_exit_queue(struct request_queue *q);
/* Blkio controller policy registration */
extern void blkio_policy_register(struct blkio_policy_type *);
extern void blkio_policy_unregister(struct blkio_policy_type *);
int blkcg_policy_register(struct blkcg_policy *pol);
void blkcg_policy_unregister(struct blkcg_policy *pol);
int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol);
void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol);
void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
u64 (*prfill)(struct seq_file *,
struct blkg_policy_data *, int),
const struct blkcg_policy *pol, int data,
bool show_total);
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
const struct blkg_rwstat *rwstat);
u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
int off);
struct blkg_conf_ctx {
struct gendisk *disk;
struct blkcg_gq *blkg;
u64 v;
};
int blkg_conf_prep(struct blkcg *blkcg, const struct blkcg_policy *pol,
const char *input, struct blkg_conf_ctx *ctx);
void blkg_conf_finish(struct blkg_conf_ctx *ctx);
/**
* blkg_to_pdata - get policy private data
* @blkg: blkg of interest
* @pol: policy of interest
*
* Return pointer to private data associated with the @blkg-@pol pair.
*/
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
struct blkcg_policy *pol)
{
return blkg ? blkg->pd[pol->plid] : NULL;
}
/**
* pdata_to_blkg - get blkg associated with policy private data
* @pd: policy private data of interest
*
* @pd is policy private data. Determine the blkg it's associated with.
*/
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd)
{
return pd ? pd->blkg : NULL;
}
/**
* blkg_path - format cgroup path of blkg
* @blkg: blkg of interest
* @buf: target buffer
* @buflen: target buffer length
*
* Format the path of the cgroup of @blkg into @buf.
*/
static inline int blkg_path(struct blkcg_gq *blkg, char *buf, int buflen)
{
int ret;
rcu_read_lock();
ret = cgroup_path(blkg->blkcg->css.cgroup, buf, buflen);
rcu_read_unlock();
if (ret)
strncpy(buf, "<unavailable>", buflen);
return ret;
}
/**
* blkg_get - get a blkg reference
* @blkg: blkg to get
*
* The caller should be holding queue_lock and an existing reference.
*/
static inline void blkg_get(struct blkcg_gq *blkg)
{
lockdep_assert_held(blkg->q->queue_lock);
WARN_ON_ONCE(!blkg->refcnt);
blkg->refcnt++;
}
static inline char *blkg_path(struct blkio_group *blkg)
void __blkg_release(struct blkcg_gq *blkg);
/**
* blkg_put - put a blkg reference
* @blkg: blkg to put
*
* The caller should be holding queue_lock.
*/
static inline void blkg_put(struct blkcg_gq *blkg)
{
lockdep_assert_held(blkg->q->queue_lock);
WARN_ON_ONCE(blkg->refcnt <= 0);
if (!--blkg->refcnt)
__blkg_release(blkg);
}
/**
* blkg_stat_add - add a value to a blkg_stat
* @stat: target blkg_stat
* @val: value to add
*
* Add @val to @stat. The caller is responsible for synchronizing calls to
* this function.
*/
static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
{
u64_stats_update_begin(&stat->syncp);
stat->cnt += val;
u64_stats_update_end(&stat->syncp);
}
/**
* blkg_stat_read - read the current value of a blkg_stat
* @stat: blkg_stat to read
*
* Read the current value of @stat. This function can be called without
* synchroniztion and takes care of u64 atomicity.
*/
static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
{
unsigned int start;
uint64_t v;
do {
start = u64_stats_fetch_begin(&stat->syncp);
v = stat->cnt;
} while (u64_stats_fetch_retry(&stat->syncp, start));
return v;
}
/**
* blkg_stat_reset - reset a blkg_stat
* @stat: blkg_stat to reset
*/
static inline void blkg_stat_reset(struct blkg_stat *stat)
{
stat->cnt = 0;
}
/**
* blkg_rwstat_add - add a value to a blkg_rwstat
* @rwstat: target blkg_rwstat
* @rw: mask of REQ_{WRITE|SYNC}
* @val: value to add
*
* Add @val to @rwstat. The counters are chosen according to @rw. The
* caller is responsible for synchronizing calls to this function.
*/
static inline void blkg_rwstat_add(struct blkg_rwstat *rwstat,
int rw, uint64_t val)
{
u64_stats_update_begin(&rwstat->syncp);
if (rw & REQ_WRITE)
rwstat->cnt[BLKG_RWSTAT_WRITE] += val;
else
rwstat->cnt[BLKG_RWSTAT_READ] += val;
if (rw & REQ_SYNC)
rwstat->cnt[BLKG_RWSTAT_SYNC] += val;
else
rwstat->cnt[BLKG_RWSTAT_ASYNC] += val;
u64_stats_update_end(&rwstat->syncp);
}
/**
* blkg_rwstat_read - read the current values of a blkg_rwstat
* @rwstat: blkg_rwstat to read
*
* Read the current snapshot of @rwstat and return it as the return value.
* This function can be called without synchronization and takes care of
* u64 atomicity.
*/
static inline struct blkg_rwstat blkg_rwstat_read(struct blkg_rwstat *rwstat)
{
return blkg->path;
unsigned int start;
struct blkg_rwstat tmp;
do {
start = u64_stats_fetch_begin(&rwstat->syncp);
tmp = *rwstat;
} while (u64_stats_fetch_retry(&rwstat->syncp, start));
return tmp;
}
#else
/**
* blkg_rwstat_sum - read the total count of a blkg_rwstat
* @rwstat: blkg_rwstat to read
*
* Return the total count of @rwstat regardless of the IO direction. This
* function can be called without synchronization and takes care of u64
* atomicity.
*/
static inline uint64_t blkg_rwstat_sum(struct blkg_rwstat *rwstat)
{
struct blkg_rwstat tmp = blkg_rwstat_read(rwstat);
struct blkio_group {
return tmp.cnt[BLKG_RWSTAT_READ] + tmp.cnt[BLKG_RWSTAT_WRITE];
}
/**
* blkg_rwstat_reset - reset a blkg_rwstat
* @rwstat: blkg_rwstat to reset
*/
static inline void blkg_rwstat_reset(struct blkg_rwstat *rwstat)
{
memset(rwstat->cnt, 0, sizeof(rwstat->cnt));
}
#else /* CONFIG_BLK_CGROUP */
struct cgroup;
struct blkg_policy_data {
};
struct blkio_policy_type {
struct blkcg_gq {
};
static inline void blkio_policy_register(struct blkio_policy_type *blkiop) { }
static inline void blkio_policy_unregister(struct blkio_policy_type *blkiop) { }
static inline char *blkg_path(struct blkio_group *blkg) { return NULL; }
#endif
#define BLKIO_WEIGHT_MIN 10
#define BLKIO_WEIGHT_MAX 1000
#define BLKIO_WEIGHT_DEFAULT 500
#ifdef CONFIG_DEBUG_BLK_CGROUP
void blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg);
void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue);
void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg);
void blkiocg_update_idle_time_stats(struct blkio_group *blkg);
void blkiocg_set_start_empty_time(struct blkio_group *blkg);
#define BLKG_FLAG_FNS(name) \
static inline void blkio_mark_blkg_##name( \
struct blkio_group_stats *stats) \
{ \
stats->flags |= (1 << BLKG_##name); \
} \
static inline void blkio_clear_blkg_##name( \
struct blkio_group_stats *stats) \
{ \
stats->flags &= ~(1 << BLKG_##name); \
} \
static inline int blkio_blkg_##name(struct blkio_group_stats *stats) \
{ \
return (stats->flags & (1 << BLKG_##name)) != 0; \
} \
BLKG_FLAG_FNS(waiting)
BLKG_FLAG_FNS(idling)
BLKG_FLAG_FNS(empty)
#undef BLKG_FLAG_FNS
#else
static inline void blkiocg_update_avg_queue_size_stats(
struct blkio_group *blkg) {}
static inline void blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue) {}
static inline void blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
{}
static inline void blkiocg_update_idle_time_stats(struct blkio_group *blkg) {}
static inline void blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
#endif
#if defined(CONFIG_BLK_CGROUP) || defined(CONFIG_BLK_CGROUP_MODULE)
extern struct blkio_cgroup blkio_root_cgroup;
extern struct blkio_cgroup *cgroup_to_blkio_cgroup(struct cgroup *cgroup);
extern struct blkio_cgroup *task_blkio_cgroup(struct task_struct *tsk);
extern void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid);
extern int blkio_alloc_blkg_stats(struct blkio_group *blkg);
extern int blkiocg_del_blkio_group(struct blkio_group *blkg);
extern struct blkio_group *blkiocg_lookup_group(struct blkio_cgroup *blkcg,
void *key);
void blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time,
unsigned long unaccounted_time);
void blkiocg_update_dispatch_stats(struct blkio_group *blkg, uint64_t bytes,
bool direction, bool sync);
void blkiocg_update_completion_stats(struct blkio_group *blkg,
uint64_t start_time, uint64_t io_start_time, bool direction, bool sync);
void blkiocg_update_io_merged_stats(struct blkio_group *blkg, bool direction,
bool sync);
void blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync);
void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync);
#else
struct cgroup;
static inline struct blkio_cgroup *
cgroup_to_blkio_cgroup(struct cgroup *cgroup) { return NULL; }
static inline struct blkio_cgroup *
task_blkio_cgroup(struct task_struct *tsk) { return NULL; }
static inline void blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev,
enum blkio_policy_id plid) {}
static inline int blkio_alloc_blkg_stats(struct blkio_group *blkg) { return 0; }
static inline int
blkiocg_del_blkio_group(struct blkio_group *blkg) { return 0; }
static inline struct blkio_group *
blkiocg_lookup_group(struct blkio_cgroup *blkcg, void *key) { return NULL; }
static inline void blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time,
unsigned long unaccounted_time)
{}
static inline void blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync) {}
static inline void blkiocg_update_completion_stats(struct blkio_group *blkg,
uint64_t start_time, uint64_t io_start_time, bool direction,
bool sync) {}
static inline void blkiocg_update_io_merged_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
static inline void blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync) {}
static inline void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
#endif
struct blkcg_policy {
};
static inline struct blkcg *cgroup_to_blkcg(struct cgroup *cgroup) { return NULL; }
static inline struct blkcg *bio_blkcg(struct bio *bio) { return NULL; }
static inline struct blkcg_gq *blkg_lookup(struct blkcg *blkcg, void *key) { return NULL; }
static inline int blkcg_init_queue(struct request_queue *q) { return 0; }
static inline void blkcg_drain_queue(struct request_queue *q) { }
static inline void blkcg_exit_queue(struct request_queue *q) { }
static inline int blkcg_policy_register(struct blkcg_policy *pol) { return 0; }
static inline void blkcg_policy_unregister(struct blkcg_policy *pol) { }
static inline int blkcg_activate_policy(struct request_queue *q,
const struct blkcg_policy *pol) { return 0; }
static inline void blkcg_deactivate_policy(struct request_queue *q,
const struct blkcg_policy *pol) { }
static inline struct blkg_policy_data *blkg_to_pd(struct blkcg_gq *blkg,
struct blkcg_policy *pol) { return NULL; }
static inline struct blkcg_gq *pd_to_blkg(struct blkg_policy_data *pd) { return NULL; }
static inline char *blkg_path(struct blkcg_gq *blkg) { return NULL; }
static inline void blkg_get(struct blkcg_gq *blkg) { }
static inline void blkg_put(struct blkcg_gq *blkg) { }
#endif /* CONFIG_BLK_CGROUP */
#endif /* _BLK_CGROUP_H */
block/blk-core.c
View file @ 0d167518
......@@ -29,11 +29,13 @@
#include <linux/fault-inject.h>
#include <linux/list_sort.h>
#include <linux/delay.h>
#include <linux/ratelimit.h>
#define CREATE_TRACE_POINTS
#include <trace/events/block.h>
#include "blk.h"
#include "blk-cgroup.h"
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_remap);
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
......@@ -280,7 +282,7 @@ EXPORT_SYMBOL(blk_stop_queue);
*
* This function does not cancel any asynchronous activity arising
* out of elevator or throttling code. That would require elevaotor_exit()
* and blk_throtl_exit() to be called with queue lock initialized.
* and blkcg_exit_queue() to be called with queue lock initialized.
*
*/
void blk_sync_queue(struct request_queue *q)
......@@ -365,17 +367,23 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
spin_lock_irq(q->queue_lock);
/*
* The caller might be trying to drain @q before its
* elevator is initialized.
*/
if (q->elevator)
elv_drain_elevator(q);
if (drain_all)
blk_throtl_drain(q);
blkcg_drain_queue(q);
/*
* This function might be called on a queue which failed
* driver init after queue creation. Some drivers
* (e.g. fd) get unhappy in such cases. Kick queue iff
* dispatch queue has something on it.
* driver init after queue creation or is not yet fully
* active yet. Some drivers (e.g. fd and loop) get unhappy
* in such cases. Kick queue iff dispatch queue has
* something on it and @q has request_fn set.
*/
if (!list_empty(&q->queue_head))
if (!list_empty(&q->queue_head) && q->request_fn)
__blk_run_queue(q);
drain |= q->rq.elvpriv;
......@@ -402,6 +410,49 @@ void blk_drain_queue(struct request_queue *q, bool drain_all)
}
}
/**
* blk_queue_bypass_start - enter queue bypass mode
* @q: queue of interest
*
* In bypass mode, only the dispatch FIFO queue of @q is used. This
* function makes @q enter bypass mode and drains all requests which were
* throttled or issued before. On return, it's guaranteed that no request
* is being throttled or has ELVPRIV set and blk_queue_bypass() %true
* inside queue or RCU read lock.
*/
void blk_queue_bypass_start(struct request_queue *q)
{
bool drain;
spin_lock_irq(q->queue_lock);
drain = !q->bypass_depth++;
queue_flag_set(QUEUE_FLAG_BYPASS, q);
spin_unlock_irq(q->queue_lock);
if (drain) {
blk_drain_queue(q, false);
/* ensure blk_queue_bypass() is %true inside RCU read lock */
synchronize_rcu();
}
}
EXPORT_SYMBOL_GPL(blk_queue_bypass_start);
/**
* blk_queue_bypass_end - leave queue bypass mode
* @q: queue of interest
*
* Leave bypass mode and restore the normal queueing behavior.
*/
void blk_queue_bypass_end(struct request_queue *q)
{
spin_lock_irq(q->queue_lock);
if (!--q->bypass_depth)
queue_flag_clear(QUEUE_FLAG_BYPASS, q);
WARN_ON_ONCE(q->bypass_depth < 0);
spin_unlock_irq(q->queue_lock);
}
EXPORT_SYMBOL_GPL(blk_queue_bypass_end);
/**
* blk_cleanup_queue - shutdown a request queue
* @q: request queue to shutdown
......@@ -418,6 +469,19 @@ void blk_cleanup_queue(struct request_queue *q)
queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
spin_lock_irq(lock);
/*
* Dead queue is permanently in bypass mode till released. Note
* that, unlike blk_queue_bypass_start(), we aren't performing
* synchronize_rcu() after entering bypass mode to avoid the delay
* as some drivers create and destroy a lot of queues while
* probing. This is still safe because blk_release_queue() will be
* called only after the queue refcnt drops to zero and nothing,
* RCU or not, would be traversing the queue by then.
*/
q->bypass_depth++;
queue_flag_set(QUEUE_FLAG_BYPASS, q);
queue_flag_set(QUEUE_FLAG_NOMERGES, q);
queue_flag_set(QUEUE_FLAG_NOXMERGES, q);
queue_flag_set(QUEUE_FLAG_DEAD, q);
......@@ -428,12 +492,7 @@ void blk_cleanup_queue(struct request_queue *q)
spin_unlock_irq(lock);
mutex_unlock(&q->sysfs_lock);
/*
* Drain all requests queued before DEAD marking. The caller might
* be trying to tear down @q before its elevator is initialized, in
* which case we don't want to call into draining.
*/
if (q->elevator)
/* drain all requests queued before DEAD marking */
blk_drain_queue(q, true);
/* @q won't process any more request, flush async actions */
......@@ -498,14 +557,15 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
if (err)
goto fail_id;
if (blk_throtl_init(q))
goto fail_id;
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
laptop_mode_timer_fn, (unsigned long) q);
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
INIT_LIST_HEAD(&q->queue_head);
INIT_LIST_HEAD(&q->timeout_list);
INIT_LIST_HEAD(&q->icq_list);
#ifdef CONFIG_BLK_CGROUP
INIT_LIST_HEAD(&q->blkg_list);
#endif
INIT_LIST_HEAD(&q->flush_queue[0]);
INIT_LIST_HEAD(&q->flush_queue[1]);
INIT_LIST_HEAD(&q->flush_data_in_flight);
......@@ -522,6 +582,18 @@ struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
*/
q->queue_lock = &q->__queue_lock;
/*
* A queue starts its life with bypass turned on to avoid
* unnecessary bypass on/off overhead and nasty surprises during
* init. The initial bypass will be finished at the end of
* blk_init_allocated_queue().
*/
q->bypass_depth = 1;
__set_bit(QUEUE_FLAG_BYPASS, &q->queue_flags);
if (blkcg_init_queue(q))
goto fail_id;
return q;
fail_id:
......@@ -614,15 +686,15 @@ blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
q->sg_reserved_size = INT_MAX;
/*
* all done
*/
if (!elevator_init(q, NULL)) {
/* init elevator */
if (elevator_init(q, NULL))
return NULL;
blk_queue_congestion_threshold(q);
return q;
}
return NULL;
/* all done, end the initial bypass */
blk_queue_bypass_end(q);
return q;
}
EXPORT_SYMBOL(blk_init_allocated_queue);
......@@ -648,33 +720,6 @@ static inline void blk_free_request(struct request_queue *q, struct request *rq)
mempool_free(rq, q->rq.rq_pool);
}
static struct request *
blk_alloc_request(struct request_queue *q, struct io_cq *icq,
unsigned int flags, gfp_t gfp_mask)
{
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
if (!rq)
return NULL;
blk_rq_init(q, rq);
rq->cmd_flags = flags | REQ_ALLOCED;
if (flags & REQ_ELVPRIV) {
rq->elv.icq = icq;
if (unlikely(elv_set_request(q, rq, gfp_mask))) {
mempool_free(rq, q->rq.rq_pool);
return NULL;
}
/* @rq->elv.icq holds on to io_context until @rq is freed */
if (icq)
get_io_context(icq->ioc);
}
return rq;
}
/*
* ioc_batching returns true if the ioc is a valid batching request and
* should be given priority access to a request.
......@@ -762,6 +807,22 @@ static bool blk_rq_should_init_elevator(struct bio *bio)
return true;
}
/**
* rq_ioc - determine io_context for request allocation
* @bio: request being allocated is for this bio (can be %NULL)
*
* Determine io_context to use for request allocation for @bio. May return
* %NULL if %current->io_context doesn't exist.
*/
static struct io_context *rq_ioc(struct bio *bio)
{
#ifdef CONFIG_BLK_CGROUP
if (bio && bio->bi_ioc)
return bio->bi_ioc;
#endif
return current->io_context;
}
/**
* get_request - get a free request
* @q: request_queue to allocate request from
......@@ -779,7 +840,7 @@ static bool blk_rq_should_init_elevator(struct bio *bio)
static struct request *get_request(struct request_queue *q, int rw_flags,
struct bio *bio, gfp_t gfp_mask)
{
struct request *rq = NULL;
struct request *rq;
struct request_list *rl = &q->rq;
struct elevator_type *et;
struct io_context *ioc;
......@@ -789,7 +850,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
int may_queue;
retry:
et = q->elevator->type;
ioc = current->io_context;
ioc = rq_ioc(bio);
if (unlikely(blk_queue_dead(q)))
return NULL;
......@@ -808,7 +869,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
*/
if (!ioc && !retried) {
spin_unlock_irq(q->queue_lock);
create_io_context(current, gfp_mask, q->node);
create_io_context(gfp_mask, q->node);
spin_lock_irq(q->queue_lock);
retried = true;
goto retry;
......@@ -831,7 +892,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
* process is not a "batcher", and not
* exempted by the IO scheduler
*/
goto out;
return NULL;
}
}
}
......@@ -844,7 +905,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
* allocated with any setting of ->nr_requests
*/
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
goto out;
return NULL;
rl->count[is_sync]++;
rl->starved[is_sync] = 0;
......@@ -859,8 +920,7 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
* Also, lookup icq while holding queue_lock. If it doesn't exist,
* it will be created after releasing queue_lock.
*/
if (blk_rq_should_init_elevator(bio) &&
!test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags)) {
if (blk_rq_should_init_elevator(bio) && !blk_queue_bypass(q)) {
rw_flags |= REQ_ELVPRIV;
rl->elvpriv++;
if (et->icq_cache && ioc)
......@@ -871,41 +931,36 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
rw_flags |= REQ_IO_STAT;
spin_unlock_irq(q->queue_lock);
/* create icq if missing */
if ((rw_flags & REQ_ELVPRIV) && unlikely(et->icq_cache && !icq)) {
icq = ioc_create_icq(q, gfp_mask);
if (!icq)
goto fail_icq;
}
rq = blk_alloc_request(q, icq, rw_flags, gfp_mask);
/* allocate and init request */
rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
if (!rq)
goto fail_alloc;
fail_icq:
if (unlikely(!rq)) {
/*
* Allocation failed presumably due to memory. Undo anything
* we might have messed up.
*
* Allocating task should really be put onto the front of the
* wait queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
freed_request(q, rw_flags);
blk_rq_init(q, rq);
rq->cmd_flags = rw_flags | REQ_ALLOCED;
/*
* in the very unlikely event that allocation failed and no
* requests for this direction was pending, mark us starved
* so that freeing of a request in the other direction will
* notice us. another possible fix would be to split the
* rq mempool into READ and WRITE
*/
rq_starved:
if (unlikely(rl->count[is_sync] == 0))
rl->starved[is_sync] = 1;
/* init elvpriv */
if (rw_flags & REQ_ELVPRIV) {
if (unlikely(et->icq_cache && !icq)) {
create_io_context(gfp_mask, q->node);
ioc = rq_ioc(bio);
if (!ioc)
goto fail_elvpriv;
goto out;
icq = ioc_create_icq(ioc, q, gfp_mask);
if (!icq)
goto fail_elvpriv;
}
rq->elv.icq = icq;
if (unlikely(elv_set_request(q, rq, bio, gfp_mask)))
goto fail_elvpriv;
/* @rq->elv.icq holds io_context until @rq is freed */
if (icq)
get_io_context(icq->ioc);
}
out:
/*
* ioc may be NULL here, and ioc_batching will be false. That's
* OK, if the queue is under the request limit then requests need
......@@ -916,8 +971,48 @@ static struct request *get_request(struct request_queue *q, int rw_flags,
ioc->nr_batch_requests--;
trace_block_getrq(q, bio, rw_flags & 1);
out:
return rq;
fail_elvpriv:
/*
* elvpriv init failed. ioc, icq and elvpriv aren't mempool backed
* and may fail indefinitely under memory pressure and thus
* shouldn't stall IO. Treat this request as !elvpriv. This will
* disturb iosched and blkcg but weird is bettern than dead.
*/
printk_ratelimited(KERN_WARNING "%s: request aux data allocation failed, iosched may be disturbed\n",
dev_name(q->backing_dev_info.dev));
rq->cmd_flags &= ~REQ_ELVPRIV;
rq->elv.icq = NULL;
spin_lock_irq(q->queue_lock);
rl->elvpriv--;
spin_unlock_irq(q->queue_lock);
goto out;
fail_alloc:
/*
* Allocation failed presumably due to memory. Undo anything we
* might have messed up.
*
* Allocating task should really be put onto the front of the wait
* queue, but this is pretty rare.
*/
spin_lock_irq(q->queue_lock);
freed_request(q, rw_flags);
/*
* in the very unlikely event that allocation failed and no
* requests for this direction was pending, mark us starved so that
* freeing of a request in the other direction will notice
* us. another possible fix would be to split the rq mempool into
* READ and WRITE
*/
rq_starved:
if (unlikely(rl->count[is_sync] == 0))
rl->starved[is_sync] = 1;
return NULL;
}
/**
......@@ -961,7 +1056,7 @@ static struct request *get_request_wait(struct request_queue *q, int rw_flags,
* up to a big batch of them for a small period time.
* See ioc_batching, ioc_set_batching
*/
create_io_context(current, GFP_NOIO, q->node);
create_io_context(GFP_NOIO, q->node);
ioc_set_batching(q, current->io_context);
spin_lock_irq(q->queue_lock);
......
block/blk-ioc.c
View file @ 0d167518
......@@ -155,20 +155,20 @@ void put_io_context(struct io_context *ioc)
}
EXPORT_SYMBOL(put_io_context);
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
/**
* put_io_context_active - put active reference on ioc
* @ioc: ioc of interest
*
* Undo get_io_context_active(). If active reference reaches zero after
* put, @ioc can never issue further IOs and ioscheds are notified.
*/
void put_io_context_active(struct io_context *ioc)
{
struct io_context *ioc;
struct io_cq *icq;
struct hlist_node *n;
unsigned long flags;
struct io_cq *icq;
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
if (!atomic_dec_and_test(&ioc->nr_tasks)) {
if (!atomic_dec_and_test(&ioc->active_ref)) {
put_io_context(ioc);
return;
}
......@@ -197,6 +197,20 @@ void exit_io_context(struct task_struct *task)
put_io_context(ioc);
}
/* Called by the exiting task */
void exit_io_context(struct task_struct *task)
{
struct io_context *ioc;
task_lock(task);
ioc = task->io_context;
task->io_context = NULL;
task_unlock(task);
atomic_dec(&ioc->nr_tasks);
put_io_context_active(ioc);
}
/**
* ioc_clear_queue - break any ioc association with the specified queue
* @q: request_queue being cleared
......@@ -218,19 +232,18 @@ void ioc_clear_queue(struct request_queue *q)
}
}
void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
int node)
int create_task_io_context(struct task_struct *task, gfp_t gfp_flags, int node)
{
struct io_context *ioc;
ioc = kmem_cache_alloc_node(iocontext_cachep, gfp_flags | __GFP_ZERO,
node);
if (unlikely(!ioc))
return;
return -ENOMEM;
/* initialize */
atomic_long_set(&ioc->refcount, 1);
atomic_set(&ioc->nr_tasks, 1);
atomic_set(&ioc->active_ref, 1);
spin_lock_init(&ioc->lock);
INIT_RADIX_TREE(&ioc->icq_tree, GFP_ATOMIC | __GFP_HIGH);
INIT_HLIST_HEAD(&ioc->icq_list);
......@@ -250,6 +263,8 @@ void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_flags,
else
kmem_cache_free(iocontext_cachep, ioc);
task_unlock(task);
return 0;
}
/**
......@@ -281,7 +296,7 @@ struct io_context *get_task_io_context(struct task_struct *task,
return ioc;
}
task_unlock(task);
} while (create_io_context(task, gfp_flags, node));
} while (!create_task_io_context(task, gfp_flags, node));
return NULL;
}
......@@ -325,26 +340,23 @@ EXPORT_SYMBOL(ioc_lookup_icq);
/**
* ioc_create_icq - create and link io_cq
* @ioc: io_context of interest
* @q: request_queue of interest
* @gfp_mask: allocation mask
*
* Make sure io_cq linking %current->io_context and @q exists. If either
* io_context and/or icq don't exist, they will be created using @gfp_mask.
* Make sure io_cq linking @ioc and @q exists. If icq doesn't exist, they
* will be created using @gfp_mask.
*
* The caller is responsible for ensuring @ioc won't go away and @q is
* alive and will stay alive until this function returns.
*/
struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
gfp_t gfp_mask)
{
struct elevator_type *et = q->elevator->type;
struct io_context *ioc;
struct io_cq *icq;
/* allocate stuff */
ioc = create_io_context(current, gfp_mask, q->node);
if (!ioc)
return NULL;
icq = kmem_cache_alloc_node(et->icq_cache, gfp_mask | __GFP_ZERO,
q->node);
if (!icq)
......@@ -382,74 +394,6 @@ struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask)
return icq;
}
void ioc_set_icq_flags(struct io_context *ioc, unsigned int flags)
{
struct io_cq *icq;
struct hlist_node *n;
hlist_for_each_entry(icq, n, &ioc->icq_list, ioc_node)
icq->flags |= flags;
}
/**
* ioc_ioprio_changed - notify ioprio change
* @ioc: io_context of interest
* @ioprio: new ioprio
*
* @ioc's ioprio has changed to @ioprio. Set %ICQ_IOPRIO_CHANGED for all
* icq's. iosched is responsible for checking the bit and applying it on
* request issue path.
*/
void ioc_ioprio_changed(struct io_context *ioc, int ioprio)
{
unsigned long flags;
spin_lock_irqsave(&ioc->lock, flags);
ioc->ioprio = ioprio;
ioc_set_icq_flags(ioc, ICQ_IOPRIO_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}
/**
* ioc_cgroup_changed - notify cgroup change
* @ioc: io_context of interest
*
* @ioc's cgroup has changed. Set %ICQ_CGROUP_CHANGED for all icq's.
* iosched is responsible for checking the bit and applying it on request
* issue path.
*/
void ioc_cgroup_changed(struct io_context *ioc)
{
unsigned long flags;
spin_lock_irqsave(&ioc->lock, flags);
ioc_set_icq_flags(ioc, ICQ_CGROUP_CHANGED);
spin_unlock_irqrestore(&ioc->lock, flags);
}
EXPORT_SYMBOL(ioc_cgroup_changed);
/**
* icq_get_changed - fetch and clear icq changed mask
* @icq: icq of interest
*
* Fetch and clear ICQ_*_CHANGED bits from @icq. Grabs and releases
* @icq->ioc->lock.
*/
unsigned icq_get_changed(struct io_cq *icq)
{
unsigned int changed = 0;
unsigned long flags;
if (unlikely(icq->flags & ICQ_CHANGED_MASK)) {
spin_lock_irqsave(&icq->ioc->lock, flags);
changed = icq->flags & ICQ_CHANGED_MASK;
icq->flags &= ~ICQ_CHANGED_MASK;
spin_unlock_irqrestore(&icq->ioc->lock, flags);
}
return changed;
}
EXPORT_SYMBOL(icq_get_changed);
static int __init blk_ioc_init(void)
{
iocontext_cachep = kmem_cache_create("blkdev_ioc",
......
block/blk-sysfs.c
View file @ 0d167518
......@@ -9,6 +9,7 @@
#include <linux/blktrace_api.h>
#include "blk.h"
#include "blk-cgroup.h"
struct queue_sysfs_entry {
struct attribute attr;
......@@ -479,6 +480,8 @@ static void blk_release_queue(struct kobject *kobj)
blk_sync_queue(q);
blkcg_exit_queue(q);
if (q->elevator) {
spin_lock_irq(q->queue_lock);
ioc_clear_queue(q);
......@@ -486,15 +489,12 @@ static void blk_release_queue(struct kobject *kobj)
elevator_exit(q->elevator);
}
blk_throtl_exit(q);
if (rl->rq_pool)
mempool_destroy(rl->rq_pool);
if (q->queue_tags)
__blk_queue_free_tags(q);
blk_throtl_release(q);
blk_trace_shutdown(q);
bdi_destroy(&q->backing_dev_info);
......
block/blk-throttle.c
View file @ 0d167518
......@@ -21,6 +21,8 @@ static int throtl_quantum = 32;
/* Throttling is performed over 100ms slice and after that slice is renewed */
static unsigned long throtl_slice = HZ/10; /* 100 ms */
static struct blkcg_policy blkcg_policy_throtl;
/* A workqueue to queue throttle related work */
static struct workqueue_struct *kthrotld_workqueue;
static void throtl_schedule_delayed_work(struct throtl_data *td,
......@@ -38,9 +40,17 @@ struct throtl_rb_root {
#define rb_entry_tg(node) rb_entry((node), struct throtl_grp, rb_node)
/* Per-cpu group stats */
struct tg_stats_cpu {
/* total bytes transferred */
struct blkg_rwstat service_bytes;
/* total IOs serviced, post merge */
struct blkg_rwstat serviced;
};
struct throtl_grp {
/* List of throtl groups on the request queue*/
struct hlist_node tg_node;
/* must be the first member */
struct blkg_policy_data pd;
/* active throtl group service_tree member */
struct rb_node rb_node;
......@@ -52,8 +62,6 @@ struct throtl_grp {
*/
unsigned long disptime;
struct blkio_group blkg;
atomic_t ref;
unsigned int flags;
/* Two lists for READ and WRITE */
......@@ -80,18 +88,18 @@ struct throtl_grp {
/* Some throttle limits got updated for the group */
int limits_changed;
struct rcu_head rcu_head;
/* Per cpu stats pointer */
struct tg_stats_cpu __percpu *stats_cpu;
/* List of tgs waiting for per cpu stats memory to be allocated */
struct list_head stats_alloc_node;
};
struct throtl_data
{
/* List of throtl groups */
struct hlist_head tg_list;
/* service tree for active throtl groups */
struct throtl_rb_root tg_service_tree;
struct throtl_grp *root_tg;
struct request_queue *queue;
/* Total Number of queued bios on READ and WRITE lists */
......@@ -108,6 +116,33 @@ struct throtl_data
int limits_changed;
};
/* list and work item to allocate percpu group stats */
static DEFINE_SPINLOCK(tg_stats_alloc_lock);
static LIST_HEAD(tg_stats_alloc_list);
static void tg_stats_alloc_fn(struct work_struct *);
static DECLARE_DELAYED_WORK(tg_stats_alloc_work, tg_stats_alloc_fn);
static inline struct throtl_grp *pd_to_tg(struct blkg_policy_data *pd)
{
return pd ? container_of(pd, struct throtl_grp, pd) : NULL;
}
static inline struct throtl_grp *blkg_to_tg(struct blkcg_gq *blkg)
{
return pd_to_tg(blkg_to_pd(blkg, &blkcg_policy_throtl));
}
static inline struct blkcg_gq *tg_to_blkg(struct throtl_grp *tg)
{
return pd_to_blkg(&tg->pd);
}
static inline struct throtl_grp *td_root_tg(struct throtl_data *td)
{
return blkg_to_tg(td->queue->root_blkg);
}
enum tg_state_flags {
THROTL_TG_FLAG_on_rr = 0, /* on round-robin busy list */
};
......@@ -128,244 +163,150 @@ static inline int throtl_tg_##name(const struct throtl_grp *tg) \
THROTL_TG_FNS(on_rr);
#define throtl_log_tg(td, tg, fmt, args...) \
blk_add_trace_msg((td)->queue, "throtl %s " fmt, \
blkg_path(&(tg)->blkg), ##args); \
#define throtl_log_tg(td, tg, fmt, args...) do { \
char __pbuf[128]; \
\
blkg_path(tg_to_blkg(tg), __pbuf, sizeof(__pbuf)); \
blk_add_trace_msg((td)->queue, "throtl %s " fmt, __pbuf, ##args); \
} while (0)
#define throtl_log(td, fmt, args...) \
blk_add_trace_msg((td)->queue, "throtl " fmt, ##args)
static inline struct throtl_grp *tg_of_blkg(struct blkio_group *blkg)
{
if (blkg)
return container_of(blkg, struct throtl_grp, blkg);
return NULL;
}
static inline unsigned int total_nr_queued(struct throtl_data *td)
{
return td->nr_queued[0] + td->nr_queued[1];
}
static inline struct throtl_grp *throtl_ref_get_tg(struct throtl_grp *tg)
{
atomic_inc(&tg->ref);
return tg;
}
static void throtl_free_tg(struct rcu_head *head)
/*
* Worker for allocating per cpu stat for tgs. This is scheduled on the
* system_nrt_wq once there are some groups on the alloc_list waiting for
* allocation.
*/
static void tg_stats_alloc_fn(struct work_struct *work)
{
struct throtl_grp *tg;
static struct tg_stats_cpu *stats_cpu; /* this fn is non-reentrant */
struct delayed_work *dwork = to_delayed_work(work);
bool empty = false;
alloc_stats:
if (!stats_cpu) {
stats_cpu = alloc_percpu(struct tg_stats_cpu);
if (!stats_cpu) {
/* allocation failed, try again after some time */
queue_delayed_work(system_nrt_wq, dwork,
msecs_to_jiffies(10));
return;
}
}
tg = container_of(head, struct throtl_grp, rcu_head);
free_percpu(tg->blkg.stats_cpu);
kfree(tg);
}
spin_lock_irq(&tg_stats_alloc_lock);
static void throtl_put_tg(struct throtl_grp *tg)
{
BUG_ON(atomic_read(&tg->ref) <= 0);
if (!atomic_dec_and_test(&tg->ref))
return;
if (!list_empty(&tg_stats_alloc_list)) {
struct throtl_grp *tg = list_first_entry(&tg_stats_alloc_list,
struct throtl_grp,
stats_alloc_node);
swap(tg->stats_cpu, stats_cpu);
list_del_init(&tg->stats_alloc_node);
}
/*
* A group is freed in rcu manner. But having an rcu lock does not
* mean that one can access all the fields of blkg and assume these
* are valid. For example, don't try to follow throtl_data and
* request queue links.
*
* Having a reference to blkg under an rcu allows acess to only
* values local to groups like group stats and group rate limits
*/
call_rcu(&tg->rcu_head, throtl_free_tg);
empty = list_empty(&tg_stats_alloc_list);
spin_unlock_irq(&tg_stats_alloc_lock);
if (!empty)
goto alloc_stats;
}
static void throtl_init_group(struct throtl_grp *tg)
static void throtl_pd_init(struct blkcg_gq *blkg)
{
INIT_HLIST_NODE(&tg->tg_node);
struct throtl_grp *tg = blkg_to_tg(blkg);
unsigned long flags;
RB_CLEAR_NODE(&tg->rb_node);
bio_list_init(&tg->bio_lists[0]);
bio_list_init(&tg->bio_lists[1]);
tg->limits_changed = false;
/* Practically unlimited BW */
tg->bps[0] = tg->bps[1] = -1;
tg->iops[0] = tg->iops[1] = -1;
tg->bps[READ] = -1;
tg->bps[WRITE] = -1;
tg->iops[READ] = -1;
tg->iops[WRITE] = -1;
/*
* Take the initial reference that will be released on destroy
* This can be thought of a joint reference by cgroup and
* request queue which will be dropped by either request queue
* exit or cgroup deletion path depending on who is exiting first.
* Ugh... We need to perform per-cpu allocation for tg->stats_cpu
* but percpu allocator can't be called from IO path. Queue tg on
* tg_stats_alloc_list and allocate from work item.
*/
atomic_set(&tg->ref, 1);
spin_lock_irqsave(&tg_stats_alloc_lock, flags);
list_add(&tg->stats_alloc_node, &tg_stats_alloc_list);
queue_delayed_work(system_nrt_wq, &tg_stats_alloc_work, 0);
spin_unlock_irqrestore(&tg_stats_alloc_lock, flags);
}
/* Should be called with rcu read lock held (needed for blkcg) */
static void
throtl_add_group_to_td_list(struct throtl_data *td, struct throtl_grp *tg)
static void throtl_pd_exit(struct blkcg_gq *blkg)
{
hlist_add_head(&tg->tg_node, &td->tg_list);
td->nr_undestroyed_grps++;
}
static void
__throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
{
struct backing_dev_info *bdi = &td->queue->backing_dev_info;
unsigned int major, minor;
if (!tg || tg->blkg.dev)
return;
/*
* Fill in device details for a group which might not have been
* filled at group creation time as queue was being instantiated
* and driver had not attached a device yet
*/
if (bdi->dev && dev_name(bdi->dev)) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
tg->blkg.dev = MKDEV(major, minor);
}
}
/*
* Should be called with without queue lock held. Here queue lock will be
* taken rarely. It will be taken only once during life time of a group
* if need be
*/
static void
throtl_tg_fill_dev_details(struct throtl_data *td, struct throtl_grp *tg)
{
if (!tg || tg->blkg.dev)
return;
spin_lock_irq(td->queue->queue_lock);
__throtl_tg_fill_dev_details(td, tg);
spin_unlock_irq(td->queue->queue_lock);
}
static void throtl_init_add_tg_lists(struct throtl_data *td,
struct throtl_grp *tg, struct blkio_cgroup *blkcg)
{
__throtl_tg_fill_dev_details(td, tg);
/* Add group onto cgroup list */
blkiocg_add_blkio_group(blkcg, &tg->blkg, (void *)td,
tg->blkg.dev, BLKIO_POLICY_THROTL);
struct throtl_grp *tg = blkg_to_tg(blkg);
unsigned long flags;
tg->bps[READ] = blkcg_get_read_bps(blkcg, tg->blkg.dev);
tg->bps[WRITE] = blkcg_get_write_bps(blkcg, tg->blkg.dev);
tg->iops[READ] = blkcg_get_read_iops(blkcg, tg->blkg.dev);
tg->iops[WRITE] = blkcg_get_write_iops(blkcg, tg->blkg.dev);
spin_lock_irqsave(&tg_stats_alloc_lock, flags);
list_del_init(&tg->stats_alloc_node);
spin_unlock_irqrestore(&tg_stats_alloc_lock, flags);
throtl_add_group_to_td_list(td, tg);
free_percpu(tg->stats_cpu);
}
/* Should be called without queue lock and outside of rcu period */
static struct throtl_grp *throtl_alloc_tg(struct throtl_data *td)
static void throtl_pd_reset_stats(struct blkcg_gq *blkg)
{
struct throtl_grp *tg = NULL;
int ret;
struct throtl_grp *tg = blkg_to_tg(blkg);
int cpu;
tg = kzalloc_node(sizeof(*tg), GFP_ATOMIC, td->queue->node);
if (!tg)
return NULL;
if (tg->stats_cpu == NULL)
return;
ret = blkio_alloc_blkg_stats(&tg->blkg);
for_each_possible_cpu(cpu) {
struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu);
if (ret) {
kfree(tg);
return NULL;
blkg_rwstat_reset(&sc->service_bytes);
blkg_rwstat_reset(&sc->serviced);
}
throtl_init_group(tg);
return tg;
}
static struct
throtl_grp *throtl_find_tg(struct throtl_data *td, struct blkio_cgroup *blkcg)
static struct throtl_grp *throtl_lookup_tg(struct throtl_data *td,
struct blkcg *blkcg)
{
struct throtl_grp *tg = NULL;
void *key = td;
/*
* This is the common case when there are no blkio cgroups.
* Avoid lookup in this case
* This is the common case when there are no blkcgs. Avoid lookup
* in this case
*/
if (blkcg == &blkio_root_cgroup)
tg = td->root_tg;
else
tg = tg_of_blkg(blkiocg_lookup_group(blkcg, key));
if (blkcg == &blkcg_root)
return td_root_tg(td);
__throtl_tg_fill_dev_details(td, tg);
return tg;
return blkg_to_tg(blkg_lookup(blkcg, td->queue));
}
static struct throtl_grp * throtl_get_tg(struct throtl_data *td)
static struct throtl_grp *throtl_lookup_create_tg(struct throtl_data *td,
struct blkcg *blkcg)
{
struct throtl_grp *tg = NULL, *__tg = NULL;
struct blkio_cgroup *blkcg;
struct request_queue *q = td->queue;
/* no throttling for dead queue */
if (unlikely(blk_queue_dead(q)))
return NULL;
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
tg = throtl_find_tg(td, blkcg);
if (tg) {
rcu_read_unlock();
return tg;
}
/*
* Need to allocate a group. Allocation of group also needs allocation
* of per cpu stats which in-turn takes a mutex() and can block. Hence
* we need to drop rcu lock and queue_lock before we call alloc.
*/
rcu_read_unlock();
spin_unlock_irq(q->queue_lock);
tg = throtl_alloc_tg(td);
/* Group allocated and queue is still alive. take the lock */
spin_lock_irq(q->queue_lock);
/* Make sure @q is still alive */
if (unlikely(blk_queue_dead(q))) {
kfree(tg);
return NULL;
}
/*
* Initialize the new group. After sleeping, read the blkcg again.
*/
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
struct throtl_grp *tg = NULL;
/*
* If some other thread already allocated the group while we were
* not holding queue lock, free up the group
* This is the common case when there are no blkcgs. Avoid lookup
* in this case
*/
__tg = throtl_find_tg(td, blkcg);
if (__tg) {
kfree(tg);
rcu_read_unlock();
return __tg;
}
/* Group allocation failed. Account the IO to root group */
if (!tg) {
tg = td->root_tg;
return tg;
if (blkcg == &blkcg_root) {
tg = td_root_tg(td);
} else {
struct blkcg_gq *blkg;
blkg = blkg_lookup_create(blkcg, q);
/* if %NULL and @q is alive, fall back to root_tg */
if (!IS_ERR(blkg))
tg = blkg_to_tg(blkg);
else if (!blk_queue_dead(q))
tg = td_root_tg(td);
}
throtl_init_add_tg_lists(td, tg, blkcg);
rcu_read_unlock();
return tg;
}
......@@ -734,16 +675,41 @@ static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
return 0;
}
static void throtl_update_dispatch_stats(struct blkcg_gq *blkg, u64 bytes,
int rw)
{
struct throtl_grp *tg = blkg_to_tg(blkg);
struct tg_stats_cpu *stats_cpu;
unsigned long flags;
/* If per cpu stats are not allocated yet, don't do any accounting. */
if (tg->stats_cpu == NULL)
return;
/*
* Disabling interrupts to provide mutual exclusion between two
* writes on same cpu. It probably is not needed for 64bit. Not
* optimizing that case yet.
*/
local_irq_save(flags);
stats_cpu = this_cpu_ptr(tg->stats_cpu);
blkg_rwstat_add(&stats_cpu->serviced, rw, 1);
blkg_rwstat_add(&stats_cpu->service_bytes, rw, bytes);
local_irq_restore(flags);
}
static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
{
bool rw = bio_data_dir(bio);
bool sync = rw_is_sync(bio->bi_rw);
/* Charge the bio to the group */
tg->bytes_disp[rw] += bio->bi_size;
tg->io_disp[rw]++;
blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size, rw, sync);
throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw);
}
static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
......@@ -753,7 +719,7 @@ static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
bio_list_add(&tg->bio_lists[rw], bio);
/* Take a bio reference on tg */
throtl_ref_get_tg(tg);
blkg_get(tg_to_blkg(tg));
tg->nr_queued[rw]++;
td->nr_queued[rw]++;
throtl_enqueue_tg(td, tg);
......@@ -786,8 +752,8 @@ static void tg_dispatch_one_bio(struct throtl_data *td, struct throtl_grp *tg,
bio = bio_list_pop(&tg->bio_lists[rw]);
tg->nr_queued[rw]--;
/* Drop bio reference on tg */
throtl_put_tg(tg);
/* Drop bio reference on blkg */
blkg_put(tg_to_blkg(tg));
BUG_ON(td->nr_queued[rw] <= 0);
td->nr_queued[rw]--;
......@@ -865,8 +831,8 @@ static int throtl_select_dispatch(struct throtl_data *td, struct bio_list *bl)
static void throtl_process_limit_change(struct throtl_data *td)
{
struct throtl_grp *tg;
struct hlist_node *pos, *n;
struct request_queue *q = td->queue;
struct blkcg_gq *blkg, *n;
if (!td->limits_changed)
return;
......@@ -875,7 +841,9 @@ static void throtl_process_limit_change(struct throtl_data *td)
throtl_log(td, "limits changed");
hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
list_for_each_entry_safe(blkg, n, &q->blkg_list, q_node) {
struct throtl_grp *tg = blkg_to_tg(blkg);
if (!tg->limits_changed)
continue;
......@@ -973,120 +941,159 @@ throtl_schedule_delayed_work(struct throtl_data *td, unsigned long delay)
}
}
static void
throtl_destroy_tg(struct throtl_data *td, struct throtl_grp *tg)
static u64 tg_prfill_cpu_rwstat(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
/* Something wrong if we are trying to remove same group twice */
BUG_ON(hlist_unhashed(&tg->tg_node));
struct throtl_grp *tg = pd_to_tg(pd);
struct blkg_rwstat rwstat = { }, tmp;
int i, cpu;
hlist_del_init(&tg->tg_node);
for_each_possible_cpu(cpu) {
struct tg_stats_cpu *sc = per_cpu_ptr(tg->stats_cpu, cpu);
/*
* Put the reference taken at the time of creation so that when all
* queues are gone, group can be destroyed.
*/
throtl_put_tg(tg);
td->nr_undestroyed_grps--;
tmp = blkg_rwstat_read((void *)sc + off);
for (i = 0; i < BLKG_RWSTAT_NR; i++)
rwstat.cnt[i] += tmp.cnt[i];
}
return __blkg_prfill_rwstat(sf, pd, &rwstat);
}
static void throtl_release_tgs(struct throtl_data *td)
static int tg_print_cpu_rwstat(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
struct hlist_node *pos, *n;
struct throtl_grp *tg;
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
hlist_for_each_entry_safe(tg, pos, n, &td->tg_list, tg_node) {
/*
* If cgroup removal path got to blk_group first and removed
* it from cgroup list, then it will take care of destroying
* cfqg also.
*/
if (!blkiocg_del_blkio_group(&tg->blkg))
throtl_destroy_tg(td, tg);
}
blkcg_print_blkgs(sf, blkcg, tg_prfill_cpu_rwstat, &blkcg_policy_throtl,
cft->private, true);
return 0;
}
/*
* Blk cgroup controller notification saying that blkio_group object is being
* delinked as associated cgroup object is going away. That also means that
* no new IO will come in this group. So get rid of this group as soon as
* any pending IO in the group is finished.
*
* This function is called under rcu_read_lock(). key is the rcu protected
* pointer. That means "key" is a valid throtl_data pointer as long as we are
* rcu read lock.
*
* "key" was fetched from blkio_group under blkio_cgroup->lock. That means
* it should not be NULL as even if queue was going away, cgroup deltion
* path got to it first.
*/
void throtl_unlink_blkio_group(void *key, struct blkio_group *blkg)
static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
unsigned long flags;
struct throtl_data *td = key;
struct throtl_grp *tg = pd_to_tg(pd);
u64 v = *(u64 *)((void *)tg + off);
spin_lock_irqsave(td->queue->queue_lock, flags);
throtl_destroy_tg(td, tg_of_blkg(blkg));
spin_unlock_irqrestore(td->queue->queue_lock, flags);
if (v == -1)
return 0;
return __blkg_prfill_u64(sf, pd, v);
}
static void throtl_update_blkio_group_common(struct throtl_data *td,
struct throtl_grp *tg)
static u64 tg_prfill_conf_uint(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
xchg(&tg->limits_changed, true);
xchg(&td->limits_changed, true);
/* Schedule a work now to process the limit change */
throtl_schedule_delayed_work(td, 0);
struct throtl_grp *tg = pd_to_tg(pd);
unsigned int v = *(unsigned int *)((void *)tg + off);
if (v == -1)
return 0;
return __blkg_prfill_u64(sf, pd, v);
}
/*
* For all update functions, key should be a valid pointer because these
* update functions are called under blkcg_lock, that means, blkg is
* valid and in turn key is valid. queue exit path can not race because
* of blkcg_lock
*
* Can not take queue lock in update functions as queue lock under blkcg_lock
* is not allowed. Under other paths we take blkcg_lock under queue_lock.
*/
static void throtl_update_blkio_group_read_bps(void *key,
struct blkio_group *blkg, u64 read_bps)
static int tg_print_conf_u64(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->bps[READ] = read_bps;
throtl_update_blkio_group_common(td, tg);
blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_u64,
&blkcg_policy_throtl, cft->private, false);
return 0;
}
static void throtl_update_blkio_group_write_bps(void *key,
struct blkio_group *blkg, u64 write_bps)
static int tg_print_conf_uint(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
tg->bps[WRITE] = write_bps;
throtl_update_blkio_group_common(td, tg);
blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp), tg_prfill_conf_uint,
&blkcg_policy_throtl, cft->private, false);
return 0;
}
static void throtl_update_blkio_group_read_iops(void *key,
struct blkio_group *blkg, unsigned int read_iops)
static int tg_set_conf(struct cgroup *cgrp, struct cftype *cft, const char *buf,
bool is_u64)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
struct blkg_conf_ctx ctx;
struct throtl_grp *tg;
struct throtl_data *td;
int ret;
ret = blkg_conf_prep(blkcg, &blkcg_policy_throtl, buf, &ctx);
if (ret)
return ret;
tg = blkg_to_tg(ctx.blkg);
td = ctx.blkg->q->td;
if (!ctx.v)
ctx.v = -1;
if (is_u64)
*(u64 *)((void *)tg + cft->private) = ctx.v;
else
*(unsigned int *)((void *)tg + cft->private) = ctx.v;
/* XXX: we don't need the following deferred processing */
xchg(&tg->limits_changed, true);
xchg(&td->limits_changed, true);
throtl_schedule_delayed_work(td, 0);
tg->iops[READ] = read_iops;
throtl_update_blkio_group_common(td, tg);
blkg_conf_finish(&ctx);
return 0;
}
static void throtl_update_blkio_group_write_iops(void *key,
struct blkio_group *blkg, unsigned int write_iops)
static int tg_set_conf_u64(struct cgroup *cgrp, struct cftype *cft,
const char *buf)
{
struct throtl_data *td = key;
struct throtl_grp *tg = tg_of_blkg(blkg);
return tg_set_conf(cgrp, cft, buf, true);
}
tg->iops[WRITE] = write_iops;
throtl_update_blkio_group_common(td, tg);
static int tg_set_conf_uint(struct cgroup *cgrp, struct cftype *cft,
const char *buf)
{
return tg_set_conf(cgrp, cft, buf, false);
}
static struct cftype throtl_files[] = {
{
.name = "throttle.read_bps_device",
.private = offsetof(struct throtl_grp, bps[READ]),
.read_seq_string = tg_print_conf_u64,
.write_string = tg_set_conf_u64,
.max_write_len = 256,
},
{
.name = "throttle.write_bps_device",
.private = offsetof(struct throtl_grp, bps[WRITE]),
.read_seq_string = tg_print_conf_u64,
.write_string = tg_set_conf_u64,
.max_write_len = 256,
},
{
.name = "throttle.read_iops_device",
.private = offsetof(struct throtl_grp, iops[READ]),
.read_seq_string = tg_print_conf_uint,
.write_string = tg_set_conf_uint,
.max_write_len = 256,
},
{
.name = "throttle.write_iops_device",
.private = offsetof(struct throtl_grp, iops[WRITE]),
.read_seq_string = tg_print_conf_uint,
.write_string = tg_set_conf_uint,
.max_write_len = 256,
},
{
.name = "throttle.io_service_bytes",
.private = offsetof(struct tg_stats_cpu, service_bytes),
.read_seq_string = tg_print_cpu_rwstat,
},
{
.name = "throttle.io_serviced",
.private = offsetof(struct tg_stats_cpu, serviced),
.read_seq_string = tg_print_cpu_rwstat,
},
{ } /* terminate */
};
static void throtl_shutdown_wq(struct request_queue *q)
{
struct throtl_data *td = q->td;
......@@ -1094,19 +1101,13 @@ static void throtl_shutdown_wq(struct request_queue *q)
cancel_delayed_work_sync(&td->throtl_work);
}
static struct blkio_policy_type blkio_policy_throtl = {
.ops = {
.blkio_unlink_group_fn = throtl_unlink_blkio_group,
.blkio_update_group_read_bps_fn =
throtl_update_blkio_group_read_bps,
.blkio_update_group_write_bps_fn =
throtl_update_blkio_group_write_bps,
.blkio_update_group_read_iops_fn =
throtl_update_blkio_group_read_iops,
.blkio_update_group_write_iops_fn =
throtl_update_blkio_group_write_iops,
},
.plid = BLKIO_POLICY_THROTL,
static struct blkcg_policy blkcg_policy_throtl = {
.pd_size = sizeof(struct throtl_grp),
.cftypes = throtl_files,
.pd_init_fn = throtl_pd_init,
.pd_exit_fn = throtl_pd_exit,
.pd_reset_stats_fn = throtl_pd_reset_stats,
};
bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
......@@ -1114,7 +1115,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
struct throtl_data *td = q->td;
struct throtl_grp *tg;
bool rw = bio_data_dir(bio), update_disptime = true;
struct blkio_cgroup *blkcg;
struct blkcg *blkcg;
bool throttled = false;
if (bio->bi_rw & REQ_THROTTLED) {
......@@ -1122,33 +1123,31 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
goto out;
}
/* bio_associate_current() needs ioc, try creating */
create_io_context(GFP_ATOMIC, q->node);
/*
* A throtl_grp pointer retrieved under rcu can be used to access
* basic fields like stats and io rates. If a group has no rules,
* just update the dispatch stats in lockless manner and return.
*/
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
tg = throtl_find_tg(td, blkcg);
blkcg = bio_blkcg(bio);
tg = throtl_lookup_tg(td, blkcg);
if (tg) {
throtl_tg_fill_dev_details(td, tg);
if (tg_no_rule_group(tg, rw)) {
blkiocg_update_dispatch_stats(&tg->blkg, bio->bi_size,
rw, rw_is_sync(bio->bi_rw));
rcu_read_unlock();
goto out;
throtl_update_dispatch_stats(tg_to_blkg(tg),
bio->bi_size, bio->bi_rw);
goto out_unlock_rcu;
}
}
rcu_read_unlock();
/*
* Either group has not been allocated yet or it is not an unlimited
* IO group
*/
spin_lock_irq(q->queue_lock);
tg = throtl_get_tg(td);
tg = throtl_lookup_create_tg(td, blkcg);
if (unlikely(!tg))
goto out_unlock;
......@@ -1189,6 +1188,7 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
tg->io_disp[rw], tg->iops[rw],
tg->nr_queued[READ], tg->nr_queued[WRITE]);
bio_associate_current(bio);
throtl_add_bio_tg(q->td, tg, bio);
throttled = true;
......@@ -1199,6 +1199,8 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
out_unlock:
spin_unlock_irq(q->queue_lock);
out_unlock_rcu:
rcu_read_unlock();
out:
return throttled;
}
......@@ -1241,79 +1243,31 @@ void blk_throtl_drain(struct request_queue *q)
int blk_throtl_init(struct request_queue *q)
{
struct throtl_data *td;
struct throtl_grp *tg;
int ret;
td = kzalloc_node(sizeof(*td), GFP_KERNEL, q->node);
if (!td)
return -ENOMEM;
INIT_HLIST_HEAD(&td->tg_list);
td->tg_service_tree = THROTL_RB_ROOT;
td->limits_changed = false;
INIT_DELAYED_WORK(&td->throtl_work, blk_throtl_work);
/* alloc and Init root group. */
q->td = td;
td->queue = q;
tg = throtl_alloc_tg(td);
if (!tg) {
/* activate policy */
ret = blkcg_activate_policy(q, &blkcg_policy_throtl);
if (ret)
kfree(td);
return -ENOMEM;
}
td->root_tg = tg;
rcu_read_lock();
throtl_init_add_tg_lists(td, tg, &blkio_root_cgroup);
rcu_read_unlock();
/* Attach throtl data to request queue */
q->td = td;
return 0;
return ret;
}
void blk_throtl_exit(struct request_queue *q)
{
struct throtl_data *td = q->td;
bool wait = false;
BUG_ON(!td);
BUG_ON(!q->td);
throtl_shutdown_wq(q);
spin_lock_irq(q->queue_lock);
throtl_release_tgs(td);
/* If there are other groups */
if (td->nr_undestroyed_grps > 0)
wait = true;
spin_unlock_irq(q->queue_lock);
/*
* Wait for tg->blkg->key accessors to exit their grace periods.
* Do this wait only if there are other undestroyed groups out
* there (other than root group). This can happen if cgroup deletion
* path claimed the responsibility of cleaning up a group before
* queue cleanup code get to the group.
*
* Do not call synchronize_rcu() unconditionally as there are drivers
* which create/delete request queue hundreds of times during scan/boot
* and synchronize_rcu() can take significant time and slow down boot.
*/
if (wait)
synchronize_rcu();
/*
* Just being safe to make sure after previous flush if some body did
* update limits through cgroup and another work got queued, cancel
* it.
*/
throtl_shutdown_wq(q);
}
void blk_throtl_release(struct request_queue *q)
{
blkcg_deactivate_policy(q, &blkcg_policy_throtl);
kfree(q->td);
}
......@@ -1323,8 +1277,7 @@ static int __init throtl_init(void)
if (!kthrotld_workqueue)
panic("Failed to create kthrotld\n");
blkio_policy_register(&blkio_policy_throtl);
return 0;
return blkcg_policy_register(&blkcg_policy_throtl);
}
module_init(throtl_init);
block/blk.h
View file @ 0d167518
......@@ -23,7 +23,8 @@ void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
struct bio *bio);
int blk_rq_append_bio(struct request_queue *q, struct request *rq,
struct bio *bio);
void blk_drain_queue(struct request_queue *q, bool drain_all);
void blk_queue_bypass_start(struct request_queue *q);
void blk_queue_bypass_end(struct request_queue *q);
void blk_dequeue_request(struct request *rq);
void __blk_queue_free_tags(struct request_queue *q);
bool __blk_end_bidi_request(struct request *rq, int error,
......@@ -144,9 +145,6 @@ void blk_queue_congestion_threshold(struct request_queue *q);
int blk_dev_init(void);
void elv_quiesce_start(struct request_queue *q);
void elv_quiesce_end(struct request_queue *q);
/*
* Return the threshold (number of used requests) at which the queue is
......@@ -186,32 +184,30 @@ static inline int blk_do_io_stat(struct request *rq)
*/
void get_io_context(struct io_context *ioc);
struct io_cq *ioc_lookup_icq(struct io_context *ioc, struct request_queue *q);
struct io_cq *ioc_create_icq(struct request_queue *q, gfp_t gfp_mask);
struct io_cq *ioc_create_icq(struct io_context *ioc, struct request_queue *q,
gfp_t gfp_mask);
void ioc_clear_queue(struct request_queue *q);
void create_io_context_slowpath(struct task_struct *task, gfp_t gfp_mask,
int node);
int create_task_io_context(struct task_struct *task, gfp_t gfp_mask, int node);
/**
* create_io_context - try to create task->io_context
* @task: target task
* @gfp_mask: allocation mask
* @node: allocation node
*
* If @task->io_context is %NULL, allocate a new io_context and install it.
* Returns the current @task->io_context which may be %NULL if allocation
* failed.
* If %current->io_context is %NULL, allocate a new io_context and install
* it. Returns the current %current->io_context which may be %NULL if
* allocation failed.
*
* Note that this function can't be called with IRQ disabled because
* task_lock which protects @task->io_context is IRQ-unsafe.
* task_lock which protects %current->io_context is IRQ-unsafe.
*/
static inline struct io_context *create_io_context(struct task_struct *task,
gfp_t gfp_mask, int node)
static inline struct io_context *create_io_context(gfp_t gfp_mask, int node)
{
WARN_ON_ONCE(irqs_disabled());
if (unlikely(!task->io_context))
create_io_context_slowpath(task, gfp_mask, node);
return task->io_context;
if (unlikely(!current->io_context))
create_task_io_context(current, gfp_mask, node);
return current->io_context;
}
/*
......@@ -222,7 +218,6 @@ extern bool blk_throtl_bio(struct request_queue *q, struct bio *bio);
extern void blk_throtl_drain(struct request_queue *q);
extern int blk_throtl_init(struct request_queue *q);
extern void blk_throtl_exit(struct request_queue *q);
extern void blk_throtl_release(struct request_queue *q);
#else /* CONFIG_BLK_DEV_THROTTLING */
static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
{
......@@ -231,7 +226,6 @@ static inline bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
static inline void blk_throtl_drain(struct request_queue *q) { }
static inline int blk_throtl_init(struct request_queue *q) { return 0; }
static inline void blk_throtl_exit(struct request_queue *q) { }
static inline void blk_throtl_release(struct request_queue *q) { }
#endif /* CONFIG_BLK_DEV_THROTTLING */
#endif /* BLK_INTERNAL_H */
block/cfq-iosched.c
View file @ 0d167518
......@@ -15,7 +15,9 @@
#include <linux/ioprio.h>
#include <linux/blktrace_api.h>
#include "blk.h"
#include "cfq.h"
#include "blk-cgroup.h"
static struct blkcg_policy blkcg_policy_cfq __maybe_unused;
/*
* tunables
......@@ -171,8 +173,53 @@ enum wl_type_t {
SYNC_WORKLOAD = 2
};
struct cfqg_stats {
#ifdef CONFIG_CFQ_GROUP_IOSCHED
/* total bytes transferred */
struct blkg_rwstat service_bytes;
/* total IOs serviced, post merge */
struct blkg_rwstat serviced;
/* number of ios merged */
struct blkg_rwstat merged;
/* total time spent on device in ns, may not be accurate w/ queueing */
struct blkg_rwstat service_time;
/* total time spent waiting in scheduler queue in ns */
struct blkg_rwstat wait_time;
/* number of IOs queued up */
struct blkg_rwstat queued;
/* total sectors transferred */
struct blkg_stat sectors;
/* total disk time and nr sectors dispatched by this group */
struct blkg_stat time;
#ifdef CONFIG_DEBUG_BLK_CGROUP
/* time not charged to this cgroup */
struct blkg_stat unaccounted_time;
/* sum of number of ios queued across all samples */
struct blkg_stat avg_queue_size_sum;
/* count of samples taken for average */
struct blkg_stat avg_queue_size_samples;
/* how many times this group has been removed from service tree */
struct blkg_stat dequeue;
/* total time spent waiting for it to be assigned a timeslice. */
struct blkg_stat group_wait_time;
/* time spent idling for this blkcg_gq */
struct blkg_stat idle_time;
/* total time with empty current active q with other requests queued */
struct blkg_stat empty_time;
/* fields after this shouldn't be cleared on stat reset */
uint64_t start_group_wait_time;
uint64_t start_idle_time;
uint64_t start_empty_time;
uint16_t flags;
#endif /* CONFIG_DEBUG_BLK_CGROUP */
#endif /* CONFIG_CFQ_GROUP_IOSCHED */
};
/* This is per cgroup per device grouping structure */
struct cfq_group {
/* must be the first member */
struct blkg_policy_data pd;
/* group service_tree member */
struct rb_node rb_node;
......@@ -180,7 +227,7 @@ struct cfq_group {
u64 vdisktime;
unsigned int weight;
unsigned int new_weight;
bool needs_update;
unsigned int dev_weight;
/* number of cfqq currently on this group */
int nr_cfqq;
......@@ -206,20 +253,21 @@ struct cfq_group {
unsigned long saved_workload_slice;
enum wl_type_t saved_workload;
enum wl_prio_t saved_serving_prio;
struct blkio_group blkg;
#ifdef CONFIG_CFQ_GROUP_IOSCHED
struct hlist_node cfqd_node;
int ref;
#endif
/* number of requests that are on the dispatch list or inside driver */
int dispatched;
struct cfq_ttime ttime;
struct cfqg_stats stats;
};
struct cfq_io_cq {
struct io_cq icq; /* must be the first member */
struct cfq_queue *cfqq[2];
struct cfq_ttime ttime;
int ioprio; /* the current ioprio */
#ifdef CONFIG_CFQ_GROUP_IOSCHED
uint64_t blkcg_id; /* the current blkcg ID */
#endif
};
/*
......@@ -229,7 +277,7 @@ struct cfq_data {
struct request_queue *queue;
/* Root service tree for cfq_groups */
struct cfq_rb_root grp_service_tree;
struct cfq_group root_group;
struct cfq_group *root_group;
/*
* The priority currently being served
......@@ -303,12 +351,6 @@ struct cfq_data {
struct cfq_queue oom_cfqq;
unsigned long last_delayed_sync;
/* List of cfq groups being managed on this device*/
struct hlist_head cfqg_list;
/* Number of groups which are on blkcg->blkg_list */
unsigned int nr_blkcg_linked_grps;
};
static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd);
......@@ -371,21 +413,284 @@ CFQ_CFQQ_FNS(deep);
CFQ_CFQQ_FNS(wait_busy);
#undef CFQ_CFQQ_FNS
static inline struct cfq_group *pd_to_cfqg(struct blkg_policy_data *pd)
{
return pd ? container_of(pd, struct cfq_group, pd) : NULL;
}
static inline struct cfq_group *blkg_to_cfqg(struct blkcg_gq *blkg)
{
return pd_to_cfqg(blkg_to_pd(blkg, &blkcg_policy_cfq));
}
static inline struct blkcg_gq *cfqg_to_blkg(struct cfq_group *cfqg)
{
return pd_to_blkg(&cfqg->pd);
}
#if defined(CONFIG_CFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
/* cfqg stats flags */
enum cfqg_stats_flags {
CFQG_stats_waiting = 0,
CFQG_stats_idling,
CFQG_stats_empty,
};
#define CFQG_FLAG_FNS(name) \
static inline void cfqg_stats_mark_##name(struct cfqg_stats *stats) \
{ \
stats->flags |= (1 << CFQG_stats_##name); \
} \
static inline void cfqg_stats_clear_##name(struct cfqg_stats *stats) \
{ \
stats->flags &= ~(1 << CFQG_stats_##name); \
} \
static inline int cfqg_stats_##name(struct cfqg_stats *stats) \
{ \
return (stats->flags & (1 << CFQG_stats_##name)) != 0; \
} \
CFQG_FLAG_FNS(waiting)
CFQG_FLAG_FNS(idling)
CFQG_FLAG_FNS(empty)
#undef CFQG_FLAG_FNS
/* This should be called with the queue_lock held. */
static void cfqg_stats_update_group_wait_time(struct cfqg_stats *stats)
{
unsigned long long now;
if (!cfqg_stats_waiting(stats))
return;
now = sched_clock();
if (time_after64(now, stats->start_group_wait_time))
blkg_stat_add(&stats->group_wait_time,
now - stats->start_group_wait_time);
cfqg_stats_clear_waiting(stats);
}
/* This should be called with the queue_lock held. */
static void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg,
struct cfq_group *curr_cfqg)
{
struct cfqg_stats *stats = &cfqg->stats;
if (cfqg_stats_waiting(stats))
return;
if (cfqg == curr_cfqg)
return;
stats->start_group_wait_time = sched_clock();
cfqg_stats_mark_waiting(stats);
}
/* This should be called with the queue_lock held. */
static void cfqg_stats_end_empty_time(struct cfqg_stats *stats)
{
unsigned long long now;
if (!cfqg_stats_empty(stats))
return;
now = sched_clock();
if (time_after64(now, stats->start_empty_time))
blkg_stat_add(&stats->empty_time,
now - stats->start_empty_time);
cfqg_stats_clear_empty(stats);
}
static void cfqg_stats_update_dequeue(struct cfq_group *cfqg)
{
blkg_stat_add(&cfqg->stats.dequeue, 1);
}
static void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg)
{
struct cfqg_stats *stats = &cfqg->stats;
if (blkg_rwstat_sum(&stats->queued))
return;
/*
* group is already marked empty. This can happen if cfqq got new
* request in parent group and moved to this group while being added
* to service tree. Just ignore the event and move on.
*/
if (cfqg_stats_empty(stats))
return;
stats->start_empty_time = sched_clock();
cfqg_stats_mark_empty(stats);
}
static void cfqg_stats_update_idle_time(struct cfq_group *cfqg)
{
struct cfqg_stats *stats = &cfqg->stats;
if (cfqg_stats_idling(stats)) {
unsigned long long now = sched_clock();
if (time_after64(now, stats->start_idle_time))
blkg_stat_add(&stats->idle_time,
now - stats->start_idle_time);
cfqg_stats_clear_idling(stats);
}
}
static void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg)
{
struct cfqg_stats *stats = &cfqg->stats;
BUG_ON(cfqg_stats_idling(stats));
stats->start_idle_time = sched_clock();
cfqg_stats_mark_idling(stats);
}
static void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg)
{
struct cfqg_stats *stats = &cfqg->stats;
blkg_stat_add(&stats->avg_queue_size_sum,
blkg_rwstat_sum(&stats->queued));
blkg_stat_add(&stats->avg_queue_size_samples, 1);
cfqg_stats_update_group_wait_time(stats);
}
#else /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
static inline void cfqg_stats_set_start_group_wait_time(struct cfq_group *cfqg, struct cfq_group *curr_cfqg) { }
static inline void cfqg_stats_end_empty_time(struct cfqg_stats *stats) { }
static inline void cfqg_stats_update_dequeue(struct cfq_group *cfqg) { }
static inline void cfqg_stats_set_start_empty_time(struct cfq_group *cfqg) { }
static inline void cfqg_stats_update_idle_time(struct cfq_group *cfqg) { }
static inline void cfqg_stats_set_start_idle_time(struct cfq_group *cfqg) { }
static inline void cfqg_stats_update_avg_queue_size(struct cfq_group *cfqg) { }
#endif /* CONFIG_CFQ_GROUP_IOSCHED && CONFIG_DEBUG_BLK_CGROUP */
#ifdef CONFIG_CFQ_GROUP_IOSCHED
#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
static inline void cfqg_get(struct cfq_group *cfqg)
{
return blkg_get(cfqg_to_blkg(cfqg));
}
static inline void cfqg_put(struct cfq_group *cfqg)
{
return blkg_put(cfqg_to_blkg(cfqg));
}
#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) do { \
char __pbuf[128]; \
\
blkg_path(cfqg_to_blkg((cfqq)->cfqg), __pbuf, sizeof(__pbuf)); \
blk_add_trace_msg((cfqd)->queue, "cfq%d%c %s " fmt, (cfqq)->pid, \
cfq_cfqq_sync((cfqq)) ? 'S' : 'A', \
blkg_path(&(cfqq)->cfqg->blkg), ##args)
__pbuf, ##args); \
} while (0)
#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "%s " fmt, \
blkg_path(&(cfqg)->blkg), ##args) \
#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do { \
char __pbuf[128]; \
\
blkg_path(cfqg_to_blkg(cfqg), __pbuf, sizeof(__pbuf)); \
blk_add_trace_msg((cfqd)->queue, "%s " fmt, __pbuf, ##args); \
} while (0)
static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
struct cfq_group *curr_cfqg, int rw)
{
blkg_rwstat_add(&cfqg->stats.queued, rw, 1);
cfqg_stats_end_empty_time(&cfqg->stats);
cfqg_stats_set_start_group_wait_time(cfqg, curr_cfqg);
}
static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
unsigned long time, unsigned long unaccounted_time)
{
blkg_stat_add(&cfqg->stats.time, time);
#ifdef CONFIG_DEBUG_BLK_CGROUP
blkg_stat_add(&cfqg->stats.unaccounted_time, unaccounted_time);
#endif
}
static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw)
{
blkg_rwstat_add(&cfqg->stats.queued, rw, -1);
}
static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw)
{
blkg_rwstat_add(&cfqg->stats.merged, rw, 1);
}
static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg,
uint64_t bytes, int rw)
{
blkg_stat_add(&cfqg->stats.sectors, bytes >> 9);
blkg_rwstat_add(&cfqg->stats.serviced, rw, 1);
blkg_rwstat_add(&cfqg->stats.service_bytes, rw, bytes);
}
static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
uint64_t start_time, uint64_t io_start_time, int rw)
{
struct cfqg_stats *stats = &cfqg->stats;
unsigned long long now = sched_clock();
if (time_after64(now, io_start_time))
blkg_rwstat_add(&stats->service_time, rw, now - io_start_time);
if (time_after64(io_start_time, start_time))
blkg_rwstat_add(&stats->wait_time, rw,
io_start_time - start_time);
}
static void cfq_pd_reset_stats(struct blkcg_gq *blkg)
{
struct cfq_group *cfqg = blkg_to_cfqg(blkg);
struct cfqg_stats *stats = &cfqg->stats;
/* queued stats shouldn't be cleared */
blkg_rwstat_reset(&stats->service_bytes);
blkg_rwstat_reset(&stats->serviced);
blkg_rwstat_reset(&stats->merged);
blkg_rwstat_reset(&stats->service_time);
blkg_rwstat_reset(&stats->wait_time);
blkg_stat_reset(&stats->time);
#ifdef CONFIG_DEBUG_BLK_CGROUP
blkg_stat_reset(&stats->unaccounted_time);
blkg_stat_reset(&stats->avg_queue_size_sum);
blkg_stat_reset(&stats->avg_queue_size_samples);
blkg_stat_reset(&stats->dequeue);
blkg_stat_reset(&stats->group_wait_time);
blkg_stat_reset(&stats->idle_time);
blkg_stat_reset(&stats->empty_time);
#endif
}
#else /* CONFIG_CFQ_GROUP_IOSCHED */
static inline void cfqg_get(struct cfq_group *cfqg) { }
static inline void cfqg_put(struct cfq_group *cfqg) { }
#else
#define cfq_log_cfqq(cfqd, cfqq, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq%d " fmt, (cfqq)->pid, ##args)
#define cfq_log_cfqg(cfqd, cfqg, fmt, args...) do {} while (0)
#endif
static inline void cfqg_stats_update_io_add(struct cfq_group *cfqg,
struct cfq_group *curr_cfqg, int rw) { }
static inline void cfqg_stats_update_timeslice_used(struct cfq_group *cfqg,
unsigned long time, unsigned long unaccounted_time) { }
static inline void cfqg_stats_update_io_remove(struct cfq_group *cfqg, int rw) { }
static inline void cfqg_stats_update_io_merged(struct cfq_group *cfqg, int rw) { }
static inline void cfqg_stats_update_dispatch(struct cfq_group *cfqg,
uint64_t bytes, int rw) { }
static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
uint64_t start_time, uint64_t io_start_time, int rw) { }
#endif /* CONFIG_CFQ_GROUP_IOSCHED */
#define cfq_log(cfqd, fmt, args...) \
blk_add_trace_msg((cfqd)->queue, "cfq " fmt, ##args)
......@@ -466,8 +771,9 @@ static inline int cfqg_busy_async_queues(struct cfq_data *cfqd,
}
static void cfq_dispatch_insert(struct request_queue *, struct request *);
static struct cfq_queue *cfq_get_queue(struct cfq_data *, bool,
struct io_context *, gfp_t);
static struct cfq_queue *cfq_get_queue(struct cfq_data *cfqd, bool is_sync,
struct cfq_io_cq *cic, struct bio *bio,
gfp_t gfp_mask);
static inline struct cfq_io_cq *icq_to_cic(struct io_cq *icq)
{
......@@ -545,7 +851,7 @@ static inline u64 cfq_scale_slice(unsigned long delta, struct cfq_group *cfqg)
{
u64 d = delta << CFQ_SERVICE_SHIFT;
d = d * BLKIO_WEIGHT_DEFAULT;
d = d * CFQ_WEIGHT_DEFAULT;
do_div(d, cfqg->weight);
return d;
}
......@@ -872,9 +1178,9 @@ static void
cfq_update_group_weight(struct cfq_group *cfqg)
{
BUG_ON(!RB_EMPTY_NODE(&cfqg->rb_node));
if (cfqg->needs_update) {
if (cfqg->new_weight) {
cfqg->weight = cfqg->new_weight;
cfqg->needs_update = false;
cfqg->new_weight = 0;
}
}
......@@ -936,7 +1242,7 @@ cfq_group_notify_queue_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
cfq_log_cfqg(cfqd, cfqg, "del_from_rr group");
cfq_group_service_tree_del(st, cfqg);
cfqg->saved_workload_slice = 0;
cfq_blkiocg_update_dequeue_stats(&cfqg->blkg, 1);
cfqg_stats_update_dequeue(cfqg);
}
static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq,
......@@ -1008,178 +1314,59 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
"sl_used=%u disp=%u charge=%u iops=%u sect=%lu",
used_sl, cfqq->slice_dispatch, charge,
iops_mode(cfqd), cfqq->nr_sectors);
cfq_blkiocg_update_timeslice_used(&cfqg->blkg, used_sl,
unaccounted_sl);
cfq_blkiocg_set_start_empty_time(&cfqg->blkg);
cfqg_stats_update_timeslice_used(cfqg, used_sl, unaccounted_sl);
cfqg_stats_set_start_empty_time(cfqg);
}
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static inline struct cfq_group *cfqg_of_blkg(struct blkio_group *blkg)
{
if (blkg)
return container_of(blkg, struct cfq_group, blkg);
return NULL;
}
static void cfq_update_blkio_group_weight(void *key, struct blkio_group *blkg,
unsigned int weight)
{
struct cfq_group *cfqg = cfqg_of_blkg(blkg);
cfqg->new_weight = weight;
cfqg->needs_update = true;
}
static void cfq_init_add_cfqg_lists(struct cfq_data *cfqd,
struct cfq_group *cfqg, struct blkio_cgroup *blkcg)
{
struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
unsigned int major, minor;
/*
* Add group onto cgroup list. It might happen that bdi->dev is
* not initialized yet. Initialize this new group without major
* and minor info and this info will be filled in once a new thread
* comes for IO.
*/
if (bdi->dev) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,
(void *)cfqd, MKDEV(major, minor));
} else
cfq_blkiocg_add_blkio_group(blkcg, &cfqg->blkg,
(void *)cfqd, 0);
cfqd->nr_blkcg_linked_grps++;
cfqg->weight = blkcg_get_weight(blkcg, cfqg->blkg.dev);
/* Add group on cfqd list */
hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
}
/*
* Should be called from sleepable context. No request queue lock as per
* cpu stats are allocated dynamically and alloc_percpu needs to be called
* from sleepable context.
/**
* cfq_init_cfqg_base - initialize base part of a cfq_group
* @cfqg: cfq_group to initialize
*
* Initialize the base part which is used whether %CONFIG_CFQ_GROUP_IOSCHED
* is enabled or not.
*/
static struct cfq_group * cfq_alloc_cfqg(struct cfq_data *cfqd)
static void cfq_init_cfqg_base(struct cfq_group *cfqg)
{
struct cfq_group *cfqg = NULL;
int i, j, ret;
struct cfq_rb_root *st;
cfqg = kzalloc_node(sizeof(*cfqg), GFP_ATOMIC, cfqd->queue->node);
if (!cfqg)
return NULL;
int i, j;
for_each_cfqg_st(cfqg, i, j, st)
*st = CFQ_RB_ROOT;
RB_CLEAR_NODE(&cfqg->rb_node);
cfqg->ttime.last_end_request = jiffies;
/*
* Take the initial reference that will be released on destroy
* This can be thought of a joint reference by cgroup and
* elevator which will be dropped by either elevator exit
* or cgroup deletion path depending on who is exiting first.
*/
cfqg->ref = 1;
ret = blkio_alloc_blkg_stats(&cfqg->blkg);
if (ret) {
kfree(cfqg);
return NULL;
}
return cfqg;
}
static struct cfq_group *
cfq_find_cfqg(struct cfq_data *cfqd, struct blkio_cgroup *blkcg)
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static void cfq_pd_init(struct blkcg_gq *blkg)
{
struct cfq_group *cfqg = NULL;
void *key = cfqd;
struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
unsigned int major, minor;
struct cfq_group *cfqg = blkg_to_cfqg(blkg);
/*
* This is the common case when there are no blkio cgroups.
* Avoid lookup in this case
*/
if (blkcg == &blkio_root_cgroup)
cfqg = &cfqd->root_group;
else
cfqg = cfqg_of_blkg(blkiocg_lookup_group(blkcg, key));
if (cfqg && !cfqg->blkg.dev && bdi->dev && dev_name(bdi->dev)) {
sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
cfqg->blkg.dev = MKDEV(major, minor);
}
return cfqg;
cfq_init_cfqg_base(cfqg);
cfqg->weight = blkg->blkcg->cfq_weight;
}
/*
* Search for the cfq group current task belongs to. request_queue lock must
* be held.
*/
static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd)
static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd,
struct blkcg *blkcg)
{
struct blkio_cgroup *blkcg;
struct cfq_group *cfqg = NULL, *__cfqg = NULL;
struct request_queue *q = cfqd->queue;
struct cfq_group *cfqg = NULL;
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
cfqg = cfq_find_cfqg(cfqd, blkcg);
if (cfqg) {
rcu_read_unlock();
return cfqg;
}
/*
* Need to allocate a group. Allocation of group also needs allocation
* of per cpu stats which in-turn takes a mutex() and can block. Hence
* we need to drop rcu lock and queue_lock before we call alloc.
*
* Not taking any queue reference here and assuming that queue is
* around by the time we return. CFQ queue allocation code does
* the same. It might be racy though.
*/
rcu_read_unlock();
spin_unlock_irq(q->queue_lock);
cfqg = cfq_alloc_cfqg(cfqd);
spin_lock_irq(q->queue_lock);
rcu_read_lock();
blkcg = task_blkio_cgroup(current);
/*
* If some other thread already allocated the group while we were
* not holding queue lock, free up the group
*/
__cfqg = cfq_find_cfqg(cfqd, blkcg);
/* avoid lookup for the common case where there's no blkcg */
if (blkcg == &blkcg_root) {
cfqg = cfqd->root_group;
} else {
struct blkcg_gq *blkg;
if (__cfqg) {
kfree(cfqg);
rcu_read_unlock();
return __cfqg;
blkg = blkg_lookup_create(blkcg, q);
if (!IS_ERR(blkg))
cfqg = blkg_to_cfqg(blkg);
}
if (!cfqg)
cfqg = &cfqd->root_group;
cfq_init_add_cfqg_lists(cfqd, cfqg, blkcg);
rcu_read_unlock();
return cfqg;
}
static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
{
cfqg->ref++;
return cfqg;
}
......@@ -1187,94 +1374,224 @@ static void cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg)
{
/* Currently, all async queues are mapped to root group */
if (!cfq_cfqq_sync(cfqq))
cfqg = &cfqq->cfqd->root_group;
cfqg = cfqq->cfqd->root_group;
cfqq->cfqg = cfqg;
/* cfqq reference on cfqg */
cfqq->cfqg->ref++;
cfqg_get(cfqg);
}
static void cfq_put_cfqg(struct cfq_group *cfqg)
static u64 cfqg_prfill_weight_device(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct cfq_rb_root *st;
int i, j;
struct cfq_group *cfqg = pd_to_cfqg(pd);
BUG_ON(cfqg->ref <= 0);
cfqg->ref--;
if (cfqg->ref)
return;
for_each_cfqg_st(cfqg, i, j, st)
BUG_ON(!RB_EMPTY_ROOT(&st->rb));
free_percpu(cfqg->blkg.stats_cpu);
kfree(cfqg);
if (!cfqg->dev_weight)
return 0;
return __blkg_prfill_u64(sf, pd, cfqg->dev_weight);
}
static void cfq_destroy_cfqg(struct cfq_data *cfqd, struct cfq_group *cfqg)
static int cfqg_print_weight_device(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
/* Something wrong if we are trying to remove same group twice */
BUG_ON(hlist_unhashed(&cfqg->cfqd_node));
blkcg_print_blkgs(sf, cgroup_to_blkcg(cgrp),
cfqg_prfill_weight_device, &blkcg_policy_cfq, 0,
false);
return 0;
}
hlist_del_init(&cfqg->cfqd_node);
static int cfq_print_weight(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
seq_printf(sf, "%u\n", cgroup_to_blkcg(cgrp)->cfq_weight);
return 0;
}
BUG_ON(cfqd->nr_blkcg_linked_grps <= 0);
cfqd->nr_blkcg_linked_grps--;
static int cfqg_set_weight_device(struct cgroup *cgrp, struct cftype *cft,
const char *buf)
{
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
struct blkg_conf_ctx ctx;
struct cfq_group *cfqg;
int ret;
/*
* Put the reference taken at the time of creation so that when all
* queues are gone, group can be destroyed.
*/
cfq_put_cfqg(cfqg);
ret = blkg_conf_prep(blkcg, &blkcg_policy_cfq, buf, &ctx);
if (ret)
return ret;
ret = -EINVAL;
cfqg = blkg_to_cfqg(ctx.blkg);
if (!ctx.v || (ctx.v >= CFQ_WEIGHT_MIN && ctx.v <= CFQ_WEIGHT_MAX)) {
cfqg->dev_weight = ctx.v;
cfqg->new_weight = cfqg->dev_weight ?: blkcg->cfq_weight;
ret = 0;
}
blkg_conf_finish(&ctx);
return ret;
}
static void cfq_release_cfq_groups(struct cfq_data *cfqd)
static int cfq_set_weight(struct cgroup *cgrp, struct cftype *cft, u64 val)
{
struct hlist_node *pos, *n;
struct cfq_group *cfqg;
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
struct blkcg_gq *blkg;
struct hlist_node *n;
hlist_for_each_entry_safe(cfqg, pos, n, &cfqd->cfqg_list, cfqd_node) {
/*
* If cgroup removal path got to blk_group first and removed
* it from cgroup list, then it will take care of destroying
* cfqg also.
*/
if (!cfq_blkiocg_del_blkio_group(&cfqg->blkg))
cfq_destroy_cfqg(cfqd, cfqg);
if (val < CFQ_WEIGHT_MIN || val > CFQ_WEIGHT_MAX)
return -EINVAL;
spin_lock_irq(&blkcg->lock);
blkcg->cfq_weight = (unsigned int)val;
hlist_for_each_entry(blkg, n, &blkcg->blkg_list, blkcg_node) {
struct cfq_group *cfqg = blkg_to_cfqg(blkg);
if (cfqg && !cfqg->dev_weight)
cfqg->new_weight = blkcg->cfq_weight;
}
spin_unlock_irq(&blkcg->lock);
return 0;
}
/*
* Blk cgroup controller notification saying that blkio_group object is being
* delinked as associated cgroup object is going away. That also means that
* no new IO will come in this group. So get rid of this group as soon as
* any pending IO in the group is finished.
*
* This function is called under rcu_read_lock(). key is the rcu protected
* pointer. That means "key" is a valid cfq_data pointer as long as we are rcu
* read lock.
*
* "key" was fetched from blkio_group under blkio_cgroup->lock. That means
* it should not be NULL as even if elevator was exiting, cgroup deltion
* path got to it first.
*/
static void cfq_unlink_blkio_group(void *key, struct blkio_group *blkg)
static int cfqg_print_stat(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
unsigned long flags;
struct cfq_data *cfqd = key;
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
spin_lock_irqsave(cfqd->queue->queue_lock, flags);
cfq_destroy_cfqg(cfqd, cfqg_of_blkg(blkg));
spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
blkcg_print_blkgs(sf, blkcg, blkg_prfill_stat, &blkcg_policy_cfq,
cft->private, false);
return 0;
}
#else /* GROUP_IOSCHED */
static struct cfq_group *cfq_get_cfqg(struct cfq_data *cfqd)
static int cfqg_print_rwstat(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
return &cfqd->root_group;
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
blkcg_print_blkgs(sf, blkcg, blkg_prfill_rwstat, &blkcg_policy_cfq,
cft->private, true);
return 0;
}
static inline struct cfq_group *cfq_ref_get_cfqg(struct cfq_group *cfqg)
#ifdef CONFIG_DEBUG_BLK_CGROUP
static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
return cfqg;
struct cfq_group *cfqg = pd_to_cfqg(pd);
u64 samples = blkg_stat_read(&cfqg->stats.avg_queue_size_samples);
u64 v = 0;
if (samples) {
v = blkg_stat_read(&cfqg->stats.avg_queue_size_sum);
do_div(v, samples);
}
__blkg_prfill_u64(sf, pd, v);
return 0;
}
/* print avg_queue_size */
static int cfqg_print_avg_queue_size(struct cgroup *cgrp, struct cftype *cft,
struct seq_file *sf)
{
struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
blkcg_print_blkgs(sf, blkcg, cfqg_prfill_avg_queue_size,
&blkcg_policy_cfq, 0, false);
return 0;
}
#endif /* CONFIG_DEBUG_BLK_CGROUP */
static struct cftype cfq_blkcg_files[] = {
{
.name = "weight_device",
.read_seq_string = cfqg_print_weight_device,
.write_string = cfqg_set_weight_device,
.max_write_len = 256,
},
{
.name = "weight",
.read_seq_string = cfq_print_weight,
.write_u64 = cfq_set_weight,
},
{
.name = "time",
.private = offsetof(struct cfq_group, stats.time),
.read_seq_string = cfqg_print_stat,
},
{
.name = "sectors",
.private = offsetof(struct cfq_group, stats.sectors),
.read_seq_string = cfqg_print_stat,
},
{
.name = "io_service_bytes",
.private = offsetof(struct cfq_group, stats.service_bytes),
.read_seq_string = cfqg_print_rwstat,
},
{
.name = "io_serviced",
.private = offsetof(struct cfq_group, stats.serviced),
.read_seq_string = cfqg_print_rwstat,
},
{
.name = "io_service_time",
.private = offsetof(struct cfq_group, stats.service_time),
.read_seq_string = cfqg_print_rwstat,
},
{
.name = "io_wait_time",
.private = offsetof(struct cfq_group, stats.wait_time),
.read_seq_string = cfqg_print_rwstat,
},
{
.name = "io_merged",
.private = offsetof(struct cfq_group, stats.merged),
.read_seq_string = cfqg_print_rwstat,
},
{
.name = "io_queued",
.private = offsetof(struct cfq_group, stats.queued),
.read_seq_string = cfqg_print_rwstat,
},
#ifdef CONFIG_DEBUG_BLK_CGROUP
{
.name = "avg_queue_size",
.read_seq_string = cfqg_print_avg_queue_size,
},
{
.name = "group_wait_time",
.private = offsetof(struct cfq_group, stats.group_wait_time),
.read_seq_string = cfqg_print_stat,
},
{
.name = "idle_time",
.private = offsetof(struct cfq_group, stats.idle_time),
.read_seq_string = cfqg_print_stat,
},
{
.name = "empty_time",
.private = offsetof(struct cfq_group, stats.empty_time),
.read_seq_string = cfqg_print_stat,
},
{
.name = "dequeue",
.private = offsetof(struct cfq_group, stats.dequeue),
.read_seq_string = cfqg_print_stat,
},
{
.name = "unaccounted_time",
.private = offsetof(struct cfq_group, stats.unaccounted_time),
.read_seq_string = cfqg_print_stat,
},
#endif /* CONFIG_DEBUG_BLK_CGROUP */
{ } /* terminate */
};
#else /* GROUP_IOSCHED */
static struct cfq_group *cfq_lookup_create_cfqg(struct cfq_data *cfqd,
struct blkcg *blkcg)
{
return cfqd->root_group;
}
static inline void
......@@ -1282,9 +1599,6 @@ cfq_link_cfqq_cfqg(struct cfq_queue *cfqq, struct cfq_group *cfqg) {
cfqq->cfqg = cfqg;
}
static void cfq_release_cfq_groups(struct cfq_data *cfqd) {}
static inline void cfq_put_cfqg(struct cfq_group *cfqg) {}
#endif /* GROUP_IOSCHED */
/*
......@@ -1551,12 +1865,10 @@ static void cfq_reposition_rq_rb(struct cfq_queue *cfqq, struct request *rq)
{
elv_rb_del(&cfqq->sort_list, rq);
cfqq->queued[rq_is_sync(rq)]--;
cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
rq_data_dir(rq), rq_is_sync(rq));
cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags);
cfq_add_rq_rb(rq);
cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,
&cfqq->cfqd->serving_group->blkg, rq_data_dir(rq),
rq_is_sync(rq));
cfqg_stats_update_io_add(RQ_CFQG(rq), cfqq->cfqd->serving_group,
rq->cmd_flags);
}
static struct request *
......@@ -1612,8 +1924,7 @@ static void cfq_remove_request(struct request *rq)
cfq_del_rq_rb(rq);
cfqq->cfqd->rq_queued--;
cfq_blkiocg_update_io_remove_stats(&(RQ_CFQG(rq))->blkg,
rq_data_dir(rq), rq_is_sync(rq));
cfqg_stats_update_io_remove(RQ_CFQG(rq), rq->cmd_flags);
if (rq->cmd_flags & REQ_PRIO) {
WARN_ON(!cfqq->prio_pending);
cfqq->prio_pending--;
......@@ -1648,8 +1959,7 @@ static void cfq_merged_request(struct request_queue *q, struct request *req,
static void cfq_bio_merged(struct request_queue *q, struct request *req,
struct bio *bio)
{
cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(req))->blkg,
bio_data_dir(bio), cfq_bio_sync(bio));
cfqg_stats_update_io_merged(RQ_CFQG(req), bio->bi_rw);
}
static void
......@@ -1671,8 +1981,7 @@ cfq_merged_requests(struct request_queue *q, struct request *rq,
if (cfqq->next_rq == next)
cfqq->next_rq = rq;
cfq_remove_request(next);
cfq_blkiocg_update_io_merged_stats(&(RQ_CFQG(rq))->blkg,
rq_data_dir(next), rq_is_sync(next));
cfqg_stats_update_io_merged(RQ_CFQG(rq), next->cmd_flags);
cfqq = RQ_CFQQ(next);
/*
......@@ -1713,7 +2022,7 @@ static int cfq_allow_merge(struct request_queue *q, struct request *rq,
static inline void cfq_del_timer(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
del_timer(&cfqd->idle_slice_timer);
cfq_blkiocg_update_idle_time_stats(&cfqq->cfqg->blkg);
cfqg_stats_update_idle_time(cfqq->cfqg);
}
static void __cfq_set_active_queue(struct cfq_data *cfqd,
......@@ -1722,7 +2031,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
if (cfqq) {
cfq_log_cfqq(cfqd, cfqq, "set_active wl_prio:%d wl_type:%d",
cfqd->serving_prio, cfqd->serving_type);
cfq_blkiocg_update_avg_queue_size_stats(&cfqq->cfqg->blkg);
cfqg_stats_update_avg_queue_size(cfqq->cfqg);
cfqq->slice_start = 0;
cfqq->dispatch_start = jiffies;
cfqq->allocated_slice = 0;
......@@ -2043,7 +2352,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
* task has exited, don't wait
*/
cic = cfqd->active_cic;
if (!cic || !atomic_read(&cic->icq.ioc->nr_tasks))
if (!cic || !atomic_read(&cic->icq.ioc->active_ref))
return;
/*
......@@ -2070,7 +2379,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
sl = cfqd->cfq_slice_idle;
mod_timer(&cfqd->idle_slice_timer, jiffies + sl);
cfq_blkiocg_update_set_idle_time_stats(&cfqq->cfqg->blkg);
cfqg_stats_set_start_idle_time(cfqq->cfqg);
cfq_log_cfqq(cfqd, cfqq, "arm_idle: %lu group_idle: %d", sl,
group_idle ? 1 : 0);
}
......@@ -2093,8 +2402,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]++;
cfqq->nr_sectors += blk_rq_sectors(rq);
cfq_blkiocg_update_dispatch_stats(&cfqq->cfqg->blkg, blk_rq_bytes(rq),
rq_data_dir(rq), rq_is_sync(rq));
cfqg_stats_update_dispatch(cfqq->cfqg, blk_rq_bytes(rq), rq->cmd_flags);
}
/*
......@@ -2677,7 +2985,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
BUG_ON(cfq_cfqq_on_rr(cfqq));
kmem_cache_free(cfq_pool, cfqq);
cfq_put_cfqg(cfqg);
cfqg_put(cfqg);
}
static void cfq_put_cooperator(struct cfq_queue *cfqq)
......@@ -2736,7 +3044,7 @@ static void cfq_exit_icq(struct io_cq *icq)
}
}
static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
static void cfq_init_prio_data(struct cfq_queue *cfqq, struct cfq_io_cq *cic)
{
struct task_struct *tsk = current;
int ioprio_class;
......@@ -2744,7 +3052,7 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
if (!cfq_cfqq_prio_changed(cfqq))
return;
ioprio_class = IOPRIO_PRIO_CLASS(ioc->ioprio);
ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
switch (ioprio_class) {
default:
printk(KERN_ERR "cfq: bad prio %x\n", ioprio_class);
......@@ -2756,11 +3064,11 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
cfqq->ioprio_class = task_nice_ioclass(tsk);
break;
case IOPRIO_CLASS_RT:
cfqq->ioprio = task_ioprio(ioc);
cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
cfqq->ioprio_class = IOPRIO_CLASS_RT;
break;
case IOPRIO_CLASS_BE:
cfqq->ioprio = task_ioprio(ioc);
cfqq->ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
cfqq->ioprio_class = IOPRIO_CLASS_BE;
break;
case IOPRIO_CLASS_IDLE:
......@@ -2778,18 +3086,23 @@ static void cfq_init_prio_data(struct cfq_queue *cfqq, struct io_context *ioc)
cfq_clear_cfqq_prio_changed(cfqq);
}
static void changed_ioprio(struct cfq_io_cq *cic)
static void check_ioprio_changed(struct cfq_io_cq *cic, struct bio *bio)
{
int ioprio = cic->icq.ioc->ioprio;
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct cfq_queue *cfqq;
if (unlikely(!cfqd))
/*
* Check whether ioprio has changed. The condition may trigger
* spuriously on a newly created cic but there's no harm.
*/
if (unlikely(!cfqd) || likely(cic->ioprio == ioprio))
return;
cfqq = cic->cfqq[BLK_RW_ASYNC];
if (cfqq) {
struct cfq_queue *new_cfqq;
new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic->icq.ioc,
new_cfqq = cfq_get_queue(cfqd, BLK_RW_ASYNC, cic, bio,
GFP_ATOMIC);
if (new_cfqq) {
cic->cfqq[BLK_RW_ASYNC] = new_cfqq;
......@@ -2800,6 +3113,8 @@ static void changed_ioprio(struct cfq_io_cq *cic)
cfqq = cic->cfqq[BLK_RW_SYNC];
if (cfqq)
cfq_mark_cfqq_prio_changed(cfqq);
cic->ioprio = ioprio;
}
static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
......@@ -2823,17 +3138,24 @@ static void cfq_init_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq,
}
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static void changed_cgroup(struct cfq_io_cq *cic)
static void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio)
{
struct cfq_queue *sync_cfqq = cic_to_cfqq(cic, 1);
struct cfq_data *cfqd = cic_to_cfqd(cic);
struct request_queue *q;
struct cfq_queue *sync_cfqq;
uint64_t id;
if (unlikely(!cfqd))
return;
rcu_read_lock();
id = bio_blkcg(bio)->id;
rcu_read_unlock();
q = cfqd->queue;
/*
* Check whether blkcg has changed. The condition may trigger
* spuriously on a newly created cic but there's no harm.
*/
if (unlikely(!cfqd) || likely(cic->blkcg_id == id))
return;
sync_cfqq = cic_to_cfqq(cic, 1);
if (sync_cfqq) {
/*
* Drop reference to sync queue. A new sync queue will be
......@@ -2843,21 +3165,26 @@ static void changed_cgroup(struct cfq_io_cq *cic)
cic_set_cfqq(cic, NULL, 1);
cfq_put_queue(sync_cfqq);
}
cic->blkcg_id = id;
}
#else
static inline void check_blkcg_changed(struct cfq_io_cq *cic, struct bio *bio) { }
#endif /* CONFIG_CFQ_GROUP_IOSCHED */
static struct cfq_queue *
cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
struct io_context *ioc, gfp_t gfp_mask)
cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
struct bio *bio, gfp_t gfp_mask)
{
struct blkcg *blkcg;
struct cfq_queue *cfqq, *new_cfqq = NULL;
struct cfq_io_cq *cic;
struct cfq_group *cfqg;
retry:
cfqg = cfq_get_cfqg(cfqd);
cic = cfq_cic_lookup(cfqd, ioc);
/* cic always exists here */
rcu_read_lock();
blkcg = bio_blkcg(bio);
cfqg = cfq_lookup_create_cfqg(cfqd, blkcg);
cfqq = cic_to_cfqq(cic, is_sync);
/*
......@@ -2870,6 +3197,7 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
cfqq = new_cfqq;
new_cfqq = NULL;
} else if (gfp_mask & __GFP_WAIT) {
rcu_read_unlock();
spin_unlock_irq(cfqd->queue->queue_lock);
new_cfqq = kmem_cache_alloc_node(cfq_pool,
gfp_mask | __GFP_ZERO,
......@@ -2885,7 +3213,7 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
if (cfqq) {
cfq_init_cfqq(cfqd, cfqq, current->pid, is_sync);
cfq_init_prio_data(cfqq, ioc);
cfq_init_prio_data(cfqq, cic);
cfq_link_cfqq_cfqg(cfqq, cfqg);
cfq_log_cfqq(cfqd, cfqq, "alloced");
} else
......@@ -2895,6 +3223,7 @@ cfq_find_alloc_queue(struct cfq_data *cfqd, bool is_sync,
if (new_cfqq)
kmem_cache_free(cfq_pool, new_cfqq);
rcu_read_unlock();
return cfqq;
}
......@@ -2904,6 +3233,9 @@ cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
switch (ioprio_class) {
case IOPRIO_CLASS_RT:
return &cfqd->async_cfqq[0][ioprio];
case IOPRIO_CLASS_NONE:
ioprio = IOPRIO_NORM;
/* fall through */
case IOPRIO_CLASS_BE:
return &cfqd->async_cfqq[1][ioprio];
case IOPRIO_CLASS_IDLE:
......@@ -2914,11 +3246,11 @@ cfq_async_queue_prio(struct cfq_data *cfqd, int ioprio_class, int ioprio)
}
static struct cfq_queue *
cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
gfp_t gfp_mask)
cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct cfq_io_cq *cic,
struct bio *bio, gfp_t gfp_mask)
{
const int ioprio = task_ioprio(ioc);
const int ioprio_class = task_ioprio_class(ioc);
const int ioprio_class = IOPRIO_PRIO_CLASS(cic->ioprio);
const int ioprio = IOPRIO_PRIO_DATA(cic->ioprio);
struct cfq_queue **async_cfqq = NULL;
struct cfq_queue *cfqq = NULL;
......@@ -2928,7 +3260,7 @@ cfq_get_queue(struct cfq_data *cfqd, bool is_sync, struct io_context *ioc,
}
if (!cfqq)
cfqq = cfq_find_alloc_queue(cfqd, is_sync, ioc, gfp_mask);
cfqq = cfq_find_alloc_queue(cfqd, is_sync, cic, bio, gfp_mask);
/*
* pin the queue now that it's allocated, scheduler exit will prune it
......@@ -3010,7 +3342,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
if (cfqq->next_rq && (cfqq->next_rq->cmd_flags & REQ_NOIDLE))
enable_idle = 0;
else if (!atomic_read(&cic->icq.ioc->nr_tasks) ||
else if (!atomic_read(&cic->icq.ioc->active_ref) ||
!cfqd->cfq_slice_idle ||
(!cfq_cfqq_deep(cfqq) && CFQQ_SEEKY(cfqq)))
enable_idle = 0;
......@@ -3174,8 +3506,7 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfq_clear_cfqq_wait_request(cfqq);
__blk_run_queue(cfqd->queue);
} else {
cfq_blkiocg_update_idle_time_stats(
&cfqq->cfqg->blkg);
cfqg_stats_update_idle_time(cfqq->cfqg);
cfq_mark_cfqq_must_dispatch(cfqq);
}
}
......@@ -3197,14 +3528,13 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
struct cfq_queue *cfqq = RQ_CFQQ(rq);
cfq_log_cfqq(cfqd, cfqq, "insert_request");
cfq_init_prio_data(cfqq, RQ_CIC(rq)->icq.ioc);
cfq_init_prio_data(cfqq, RQ_CIC(rq));
rq_set_fifo_time(rq, jiffies + cfqd->cfq_fifo_expire[rq_is_sync(rq)]);
list_add_tail(&rq->queuelist, &cfqq->fifo);
cfq_add_rq_rb(rq);
cfq_blkiocg_update_io_add_stats(&(RQ_CFQG(rq))->blkg,
&cfqd->serving_group->blkg, rq_data_dir(rq),
rq_is_sync(rq));
cfqg_stats_update_io_add(RQ_CFQG(rq), cfqd->serving_group,
rq->cmd_flags);
cfq_rq_enqueued(cfqd, cfqq, rq);
}
......@@ -3300,9 +3630,8 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
cfqd->rq_in_driver--;
cfqq->dispatched--;
(RQ_CFQG(rq))->dispatched--;
cfq_blkiocg_update_completion_stats(&cfqq->cfqg->blkg,
rq_start_time_ns(rq), rq_io_start_time_ns(rq),
rq_data_dir(rq), rq_is_sync(rq));
cfqg_stats_update_completion(cfqq->cfqg, rq_start_time_ns(rq),
rq_io_start_time_ns(rq), rq->cmd_flags);
cfqd->rq_in_flight[cfq_cfqq_sync(cfqq)]--;
......@@ -3399,7 +3728,7 @@ static int cfq_may_queue(struct request_queue *q, int rw)
cfqq = cic_to_cfqq(cic, rw_is_sync(rw));
if (cfqq) {
cfq_init_prio_data(cfqq, cic->icq.ioc);
cfq_init_prio_data(cfqq, cic);
return __cfq_may_queue(cfqq);
}
......@@ -3421,7 +3750,7 @@ static void cfq_put_request(struct request *rq)
cfqq->allocated[rw]--;
/* Put down rq reference on cfqg */
cfq_put_cfqg(RQ_CFQG(rq));
cfqg_put(RQ_CFQG(rq));
rq->elv.priv[0] = NULL;
rq->elv.priv[1] = NULL;
......@@ -3465,32 +3794,25 @@ split_cfqq(struct cfq_io_cq *cic, struct cfq_queue *cfqq)
* Allocate cfq data structures associated with this request.
*/
static int
cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
cfq_set_request(struct request_queue *q, struct request *rq, struct bio *bio,
gfp_t gfp_mask)
{
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_io_cq *cic = icq_to_cic(rq->elv.icq);
const int rw = rq_data_dir(rq);
const bool is_sync = rq_is_sync(rq);
struct cfq_queue *cfqq;
unsigned int changed;
might_sleep_if(gfp_mask & __GFP_WAIT);
spin_lock_irq(q->queue_lock);
/* handle changed notifications */
changed = icq_get_changed(&cic->icq);
if (unlikely(changed & ICQ_IOPRIO_CHANGED))
changed_ioprio(cic);
#ifdef CONFIG_CFQ_GROUP_IOSCHED
if (unlikely(changed & ICQ_CGROUP_CHANGED))
changed_cgroup(cic);
#endif
check_ioprio_changed(cic, bio);
check_blkcg_changed(cic, bio);
new_queue:
cfqq = cic_to_cfqq(cic, is_sync);
if (!cfqq || cfqq == &cfqd->oom_cfqq) {
cfqq = cfq_get_queue(cfqd, is_sync, cic->icq.ioc, gfp_mask);
cfqq = cfq_get_queue(cfqd, is_sync, cic, bio, gfp_mask);
cic_set_cfqq(cic, cfqq, is_sync);
} else {
/*
......@@ -3516,8 +3838,9 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
cfqq->allocated[rw]++;
cfqq->ref++;
cfqg_get(cfqq->cfqg);
rq->elv.priv[0] = cfqq;
rq->elv.priv[1] = cfq_ref_get_cfqg(cfqq->cfqg);
rq->elv.priv[1] = cfqq->cfqg;
spin_unlock_irq(q->queue_lock);
return 0;
}
......@@ -3614,7 +3937,6 @@ static void cfq_exit_queue(struct elevator_queue *e)
{
struct cfq_data *cfqd = e->elevator_data;
struct request_queue *q = cfqd->queue;
bool wait = false;
cfq_shutdown_timer_wq(cfqd);
......@@ -3624,89 +3946,52 @@ static void cfq_exit_queue(struct elevator_queue *e)
__cfq_slice_expired(cfqd, cfqd->active_queue, 0);
cfq_put_async_queues(cfqd);
cfq_release_cfq_groups(cfqd);
/*
* If there are groups which we could not unlink from blkcg list,
* wait for a rcu period for them to be freed.
*/
if (cfqd->nr_blkcg_linked_grps)
wait = true;
spin_unlock_irq(q->queue_lock);
cfq_shutdown_timer_wq(cfqd);
/*
* Wait for cfqg->blkg->key accessors to exit their grace periods.
* Do this wait only if there are other unlinked groups out
* there. This can happen if cgroup deletion path claimed the
* responsibility of cleaning up a group before queue cleanup code
* get to the group.
*
* Do not call synchronize_rcu() unconditionally as there are drivers
* which create/delete request queue hundreds of times during scan/boot
* and synchronize_rcu() can take significant time and slow down boot.
*/
if (wait)
synchronize_rcu();
#ifdef CONFIG_CFQ_GROUP_IOSCHED
/* Free up per cpu stats for root group */
free_percpu(cfqd->root_group.blkg.stats_cpu);
#ifndef CONFIG_CFQ_GROUP_IOSCHED
kfree(cfqd->root_group);
#endif
blkcg_deactivate_policy(q, &blkcg_policy_cfq);
kfree(cfqd);
}
static void *cfq_init_queue(struct request_queue *q)
static int cfq_init_queue(struct request_queue *q)
{
struct cfq_data *cfqd;
int i, j;
struct cfq_group *cfqg;
struct cfq_rb_root *st;
struct blkcg_gq *blkg __maybe_unused;
int i, ret;
cfqd = kmalloc_node(sizeof(*cfqd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!cfqd)
return NULL;
return -ENOMEM;
cfqd->queue = q;
q->elevator->elevator_data = cfqd;
/* Init root service tree */
cfqd->grp_service_tree = CFQ_RB_ROOT;
/* Init root group */
cfqg = &cfqd->root_group;
for_each_cfqg_st(cfqg, i, j, st)
*st = CFQ_RB_ROOT;
RB_CLEAR_NODE(&cfqg->rb_node);
/* Give preference to root group over other groups */
cfqg->weight = 2*BLKIO_WEIGHT_DEFAULT;
/* Init root group and prefer root group over other groups by default */
#ifdef CONFIG_CFQ_GROUP_IOSCHED
/*
* Set root group reference to 2. One reference will be dropped when
* all groups on cfqd->cfqg_list are being deleted during queue exit.
* Other reference will remain there as we don't want to delete this
* group as it is statically allocated and gets destroyed when
* throtl_data goes away.
*/
cfqg->ref = 2;
ret = blkcg_activate_policy(q, &blkcg_policy_cfq);
if (ret)
goto out_free;
if (blkio_alloc_blkg_stats(&cfqg->blkg)) {
kfree(cfqg);
kfree(cfqd);
return NULL;
}
rcu_read_lock();
cfq_blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg,
(void *)cfqd, 0);
rcu_read_unlock();
cfqd->nr_blkcg_linked_grps++;
cfqd->root_group = blkg_to_cfqg(q->root_blkg);
#else
ret = -ENOMEM;
cfqd->root_group = kzalloc_node(sizeof(*cfqd->root_group),
GFP_KERNEL, cfqd->queue->node);
if (!cfqd->root_group)
goto out_free;
/* Add group on cfqd->cfqg_list */
hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
cfq_init_cfqg_base(cfqd->root_group);
#endif
cfqd->root_group->weight = 2 * CFQ_WEIGHT_DEFAULT;
/*
* Not strictly needed (since RB_ROOT just clears the node and we
* zeroed cfqd on alloc), but better be safe in case someone decides
......@@ -3718,13 +4003,17 @@ static void *cfq_init_queue(struct request_queue *q)
/*
* Our fallback cfqq if cfq_find_alloc_queue() runs into OOM issues.
* Grab a permanent reference to it, so that the normal code flow
* will not attempt to free it.
* will not attempt to free it. oom_cfqq is linked to root_group
* but shouldn't hold a reference as it'll never be unlinked. Lose
* the reference from linking right away.
*/
cfq_init_cfqq(cfqd, &cfqd->oom_cfqq, 1, 0);
cfqd->oom_cfqq.ref++;
cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, &cfqd->root_group);
cfqd->queue = q;
spin_lock_irq(q->queue_lock);
cfq_link_cfqq_cfqg(&cfqd->oom_cfqq, cfqd->root_group);
cfqg_put(cfqd->root_group);
spin_unlock_irq(q->queue_lock);
init_timer(&cfqd->idle_slice_timer);
cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
......@@ -3750,7 +4039,11 @@ static void *cfq_init_queue(struct request_queue *q)
* second, in order to have larger depth for async operations.
*/
cfqd->last_delayed_sync = jiffies - HZ;
return cfqd;
return 0;
out_free:
kfree(cfqd);
return ret;
}
/*
......@@ -3877,15 +4170,13 @@ static struct elevator_type iosched_cfq = {
};
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static struct blkio_policy_type blkio_policy_cfq = {
.ops = {
.blkio_unlink_group_fn = cfq_unlink_blkio_group,
.blkio_update_group_weight_fn = cfq_update_blkio_group_weight,
},
.plid = BLKIO_POLICY_PROP,
static struct blkcg_policy blkcg_policy_cfq = {
.pd_size = sizeof(struct cfq_group),
.cftypes = cfq_blkcg_files,
.pd_init_fn = cfq_pd_init,
.pd_reset_stats_fn = cfq_pd_reset_stats,
};
#else
static struct blkio_policy_type blkio_policy_cfq;
#endif
static int __init cfq_init(void)
......@@ -3906,24 +4197,31 @@ static int __init cfq_init(void)
#else
cfq_group_idle = 0;
#endif
ret = blkcg_policy_register(&blkcg_policy_cfq);
if (ret)
return ret;
cfq_pool = KMEM_CACHE(cfq_queue, 0);
if (!cfq_pool)
return -ENOMEM;
goto err_pol_unreg;
ret = elv_register(&iosched_cfq);
if (ret) {
kmem_cache_destroy(cfq_pool);
return ret;
}
blkio_policy_register(&blkio_policy_cfq);
if (ret)
goto err_free_pool;
return 0;
err_free_pool:
kmem_cache_destroy(cfq_pool);
err_pol_unreg:
blkcg_policy_unregister(&blkcg_policy_cfq);
return ret;
}
static void __exit cfq_exit(void)
{
blkio_policy_unregister(&blkio_policy_cfq);
blkcg_policy_unregister(&blkcg_policy_cfq);
elv_unregister(&iosched_cfq);
kmem_cache_destroy(cfq_pool);
}
......
block/cfq.h deleted 100644 → 0
View file @ 2f83766d
#ifndef _CFQ_H
#define _CFQ_H
#include "blk-cgroup.h"
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static inline void cfq_blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync)
{
blkiocg_update_io_add_stats(blkg, curr_blkg, direction, sync);
}
static inline void cfq_blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue)
{
blkiocg_update_dequeue_stats(blkg, dequeue);
}
static inline void cfq_blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time, unsigned long unaccounted_time)
{
blkiocg_update_timeslice_used(blkg, time, unaccounted_time);
}
static inline void cfq_blkiocg_set_start_empty_time(struct blkio_group *blkg)
{
blkiocg_set_start_empty_time(blkg);
}
static inline void cfq_blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync)
{
blkiocg_update_io_remove_stats(blkg, direction, sync);
}
static inline void cfq_blkiocg_update_io_merged_stats(struct blkio_group *blkg,
bool direction, bool sync)
{
blkiocg_update_io_merged_stats(blkg, direction, sync);
}
static inline void cfq_blkiocg_update_idle_time_stats(struct blkio_group *blkg)
{
blkiocg_update_idle_time_stats(blkg);
}
static inline void
cfq_blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg)
{
blkiocg_update_avg_queue_size_stats(blkg);
}
static inline void
cfq_blkiocg_update_set_idle_time_stats(struct blkio_group *blkg)
{
blkiocg_update_set_idle_time_stats(blkg);
}
static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync)
{
blkiocg_update_dispatch_stats(blkg, bytes, direction, sync);
}
static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync)
{
blkiocg_update_completion_stats(blkg, start_time, io_start_time,
direction, sync);
}
static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev) {
blkiocg_add_blkio_group(blkcg, blkg, key, dev, BLKIO_POLICY_PROP);
}
static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
{
return blkiocg_del_blkio_group(blkg);
}
#else /* CFQ_GROUP_IOSCHED */
static inline void cfq_blkiocg_update_io_add_stats(struct blkio_group *blkg,
struct blkio_group *curr_blkg, bool direction, bool sync) {}
static inline void cfq_blkiocg_update_dequeue_stats(struct blkio_group *blkg,
unsigned long dequeue) {}
static inline void cfq_blkiocg_update_timeslice_used(struct blkio_group *blkg,
unsigned long time, unsigned long unaccounted_time) {}
static inline void cfq_blkiocg_set_start_empty_time(struct blkio_group *blkg) {}
static inline void cfq_blkiocg_update_io_remove_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
static inline void cfq_blkiocg_update_io_merged_stats(struct blkio_group *blkg,
bool direction, bool sync) {}
static inline void cfq_blkiocg_update_idle_time_stats(struct blkio_group *blkg)
{
}
static inline void
cfq_blkiocg_update_avg_queue_size_stats(struct blkio_group *blkg) {}
static inline void
cfq_blkiocg_update_set_idle_time_stats(struct blkio_group *blkg) {}
static inline void cfq_blkiocg_update_dispatch_stats(struct blkio_group *blkg,
uint64_t bytes, bool direction, bool sync) {}
static inline void cfq_blkiocg_update_completion_stats(struct blkio_group *blkg, uint64_t start_time, uint64_t io_start_time, bool direction, bool sync) {}
static inline void cfq_blkiocg_add_blkio_group(struct blkio_cgroup *blkcg,
struct blkio_group *blkg, void *key, dev_t dev) {}
static inline int cfq_blkiocg_del_blkio_group(struct blkio_group *blkg)
{
return 0;
}
#endif /* CFQ_GROUP_IOSCHED */
#endif
block/deadline-iosched.c
View file @ 0d167518
......@@ -337,13 +337,13 @@ static void deadline_exit_queue(struct elevator_queue *e)
/*
* initialize elevator private data (deadline_data).
*/
static void *deadline_init_queue(struct request_queue *q)
static int deadline_init_queue(struct request_queue *q)
{
struct deadline_data *dd;
dd = kmalloc_node(sizeof(*dd), GFP_KERNEL | __GFP_ZERO, q->node);
if (!dd)
return NULL;
return -ENOMEM;
INIT_LIST_HEAD(&dd->fifo_list[READ]);
INIT_LIST_HEAD(&dd->fifo_list[WRITE]);
......@@ -354,7 +354,9 @@ static void *deadline_init_queue(struct request_queue *q)
dd->writes_starved = writes_starved;
dd->front_merges = 1;
dd->fifo_batch = fifo_batch;
return dd;
q->elevator->elevator_data = dd;
return 0;
}
/*
......
block/elevator.c
View file @ 0d167518
......@@ -38,6 +38,7 @@
#include <trace/events/block.h>
#include "blk.h"
#include "blk-cgroup.h"
static DEFINE_SPINLOCK(elv_list_lock);
static LIST_HEAD(elv_list);
......@@ -121,15 +122,6 @@ static struct elevator_type *elevator_get(const char *name)
return e;
}
static int elevator_init_queue(struct request_queue *q,
struct elevator_queue *eq)
{
eq->elevator_data = eq->type->ops.elevator_init_fn(q);
if (eq->elevator_data)
return 0;
return -ENOMEM;
}
static char chosen_elevator[ELV_NAME_MAX];
static int __init elevator_setup(char *str)
......@@ -188,7 +180,6 @@ static void elevator_release(struct kobject *kobj)
int elevator_init(struct request_queue *q, char *name)
{
struct elevator_type *e = NULL;
struct elevator_queue *eq;
int err;
if (unlikely(q->elevator))
......@@ -222,17 +213,16 @@ int elevator_init(struct request_queue *q, char *name)
}
}
eq = elevator_alloc(q, e);
if (!eq)
q->elevator = elevator_alloc(q, e);
if (!q->elevator)
return -ENOMEM;
err = elevator_init_queue(q, eq);
err = e->ops.elevator_init_fn(q);
if (err) {
kobject_put(&eq->kobj);
kobject_put(&q->elevator->kobj);
return err;
}
q->elevator = eq;
return 0;
}
EXPORT_SYMBOL(elevator_init);
......@@ -564,25 +554,6 @@ void elv_drain_elevator(struct request_queue *q)
}
}
void elv_quiesce_start(struct request_queue *q)
{
if (!q->elevator)
return;
spin_lock_irq(q->queue_lock);
queue_flag_set(QUEUE_FLAG_ELVSWITCH, q);
spin_unlock_irq(q->queue_lock);
blk_drain_queue(q, false);
}
void elv_quiesce_end(struct request_queue *q)
{
spin_lock_irq(q->queue_lock);
queue_flag_clear(QUEUE_FLAG_ELVSWITCH, q);
spin_unlock_irq(q->queue_lock);
}
void __elv_add_request(struct request_queue *q, struct request *rq, int where)
{
trace_block_rq_insert(q, rq);
......@@ -692,12 +663,13 @@ struct request *elv_former_request(struct request_queue *q, struct request *rq)
return NULL;
}
int elv_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
int elv_set_request(struct request_queue *q, struct request *rq,
struct bio *bio, gfp_t gfp_mask)
{
struct elevator_queue *e = q->elevator;
if (e->type->ops.elevator_set_req_fn)
return e->type->ops.elevator_set_req_fn(q, rq, gfp_mask);
return e->type->ops.elevator_set_req_fn(q, rq, bio, gfp_mask);
return 0;
}
......@@ -801,8 +773,9 @@ static struct kobj_type elv_ktype = {
.release = elevator_release,
};
int __elv_register_queue(struct request_queue *q, struct elevator_queue *e)
int elv_register_queue(struct request_queue *q)
{
struct elevator_queue *e = q->elevator;
int error;
error = kobject_add(&e->kobj, &q->kobj, "%s", "iosched");
......@@ -820,11 +793,6 @@ int __elv_register_queue(struct request_queue *q, struct elevator_queue *e)
}
return error;
}
int elv_register_queue(struct request_queue *q)
{
return __elv_register_queue(q, q->elevator);
}
EXPORT_SYMBOL(elv_register_queue);
void elv_unregister_queue(struct request_queue *q)
......@@ -907,53 +875,60 @@ EXPORT_SYMBOL_GPL(elv_unregister);
*/
static int elevator_switch(struct request_queue *q, struct elevator_type *new_e)
{
struct elevator_queue *old_elevator, *e;
struct elevator_queue *old = q->elevator;
bool registered = old->registered;
int err;
/* allocate new elevator */
e = elevator_alloc(q, new_e);
if (!e)
return -ENOMEM;
/*
* Turn on BYPASS and drain all requests w/ elevator private data.
* Block layer doesn't call into a quiesced elevator - all requests
* are directly put on the dispatch list without elevator data
* using INSERT_BACK. All requests have SOFTBARRIER set and no
* merge happens either.
*/
blk_queue_bypass_start(q);
/* unregister and clear all auxiliary data of the old elevator */
if (registered)
elv_unregister_queue(q);
spin_lock_irq(q->queue_lock);
ioc_clear_queue(q);
spin_unlock_irq(q->queue_lock);
err = elevator_init_queue(q, e);
/* allocate, init and register new elevator */
err = -ENOMEM;
q->elevator = elevator_alloc(q, new_e);
if (!q->elevator)
goto fail_init;
err = new_e->ops.elevator_init_fn(q);
if (err) {
kobject_put(&e->kobj);
return err;
kobject_put(&q->elevator->kobj);
goto fail_init;
}
/* turn on BYPASS and drain all requests w/ elevator private data */
elv_quiesce_start(q);
/* unregister old queue, register new one and kill old elevator */
if (q->elevator->registered) {
elv_unregister_queue(q);
err = __elv_register_queue(q, e);
if (registered) {
err = elv_register_queue(q);
if (err)
goto fail_register;
}
/* done, clear io_cq's, switch elevators and turn off BYPASS */
spin_lock_irq(q->queue_lock);
ioc_clear_queue(q);
old_elevator = q->elevator;
q->elevator = e;
spin_unlock_irq(q->queue_lock);
/* done, kill the old one and finish */
elevator_exit(old);
blk_queue_bypass_end(q);
elevator_exit(old_elevator);
elv_quiesce_end(q);
blk_add_trace_msg(q, "elv switch: %s", e->type->elevator_name);
blk_add_trace_msg(q, "elv switch: %s", new_e->elevator_name);
return 0;
fail_register:
/*
* switch failed, exit the new io scheduler and reattach the old
* one again (along with re-adding the sysfs dir)
*/
elevator_exit(e);
elevator_exit(q->elevator);
fail_init:
/* switch failed, restore and re-register old elevator */
q->elevator = old;
elv_register_queue(q);
elv_quiesce_end(q);
blk_queue_bypass_end(q);
return err;
}
......
block/noop-iosched.c
View file @ 0d167518
......@@ -59,15 +59,17 @@ noop_latter_request(struct request_queue *q, struct request *rq)
return list_entry(rq->queuelist.next, struct request, queuelist);
}
static void *noop_init_queue(struct request_queue *q)
static int noop_init_queue(struct request_queue *q)
{
struct noop_data *nd;
nd = kmalloc_node(sizeof(*nd), GFP_KERNEL, q->node);
if (!nd)
return NULL;
return -ENOMEM;
INIT_LIST_HEAD(&nd->queue);
return nd;
q->elevator->elevator_data = nd;
return 0;
}
static void noop_exit_queue(struct elevator_queue *e)
......
fs/bio.c
View file @ 0d167518
......@@ -19,12 +19,14 @@
#include <linux/swap.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
#include <linux/iocontext.h>
#include <linux/slab.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/export.h>
#include <linux/mempool.h>
#include <linux/workqueue.h>
#include <linux/cgroup.h>
#include <scsi/sg.h> /* for struct sg_iovec */
#include <trace/events/block.h>
......@@ -418,6 +420,7 @@ void bio_put(struct bio *bio)
* last put frees it
*/
if (atomic_dec_and_test(&bio->bi_cnt)) {
bio_disassociate_task(bio);
bio->bi_next = NULL;
bio->bi_destructor(bio);
}
......@@ -1646,6 +1649,64 @@ struct bio_set *bioset_create(unsigned int pool_size, unsigned int front_pad)
}
EXPORT_SYMBOL(bioset_create);
#ifdef CONFIG_BLK_CGROUP
/**
* bio_associate_current - associate a bio with %current
* @bio: target bio
*
* Associate @bio with %current if it hasn't been associated yet. Block
* layer will treat @bio as if it were issued by %current no matter which
* task actually issues it.
*
* This function takes an extra reference of @task's io_context and blkcg
* which will be put when @bio is released. The caller must own @bio,
* ensure %current->io_context exists, and is responsible for synchronizing
* calls to this function.
*/
int bio_associate_current(struct bio *bio)
{
struct io_context *ioc;
struct cgroup_subsys_state *css;
if (bio->bi_ioc)
return -EBUSY;
ioc = current->io_context;
if (!ioc)
return -ENOENT;
/* acquire active ref on @ioc and associate */
get_io_context_active(ioc);
bio->bi_ioc = ioc;
/* associate blkcg if exists */
rcu_read_lock();
css = task_subsys_state(current, blkio_subsys_id);
if (css && css_tryget(css))
bio->bi_css = css;
rcu_read_unlock();
return 0;
}
/**
* bio_disassociate_task - undo bio_associate_current()
* @bio: target bio
*/
void bio_disassociate_task(struct bio *bio)
{
if (bio->bi_ioc) {
put_io_context(bio->bi_ioc);
bio->bi_ioc = NULL;
}
if (bio->bi_css) {
css_put(bio->bi_css);
bio->bi_css = NULL;
}
}
#endif /* CONFIG_BLK_CGROUP */
static void __init biovec_init_slabs(void)
{
int i;
......
fs/ioprio.c
View file @ 0d167518
......@@ -50,7 +50,7 @@ int set_task_ioprio(struct task_struct *task, int ioprio)
ioc = get_task_io_context(task, GFP_ATOMIC, NUMA_NO_NODE);
if (ioc) {
ioc_ioprio_changed(ioc, ioprio);
ioc->ioprio = ioprio;
put_io_context(ioc);
}
......
fs/splice.c
View file @ 0d167518
......@@ -1388,7 +1388,7 @@ static long do_splice(struct file *in, loff_t __user *off_in,
*/
static int get_iovec_page_array(const struct iovec __user *iov,
unsigned int nr_vecs, struct page **pages,
struct partial_page *partial, int aligned,
struct partial_page *partial, bool aligned,
unsigned int pipe_buffers)
{
int buffers = 0, error = 0;
......@@ -1626,7 +1626,7 @@ static long vmsplice_to_pipe(struct file *file, const struct iovec __user *iov,
return -ENOMEM;
spd.nr_pages = get_iovec_page_array(iov, nr_segs, spd.pages,
spd.partial, flags & SPLICE_F_GIFT,
spd.partial, false,
pipe->buffers);
if (spd.nr_pages <= 0)
ret = spd.nr_pages;
......
include/linux/bio.h
View file @ 0d167518
......@@ -269,6 +269,14 @@ extern struct bio_vec *bvec_alloc_bs(gfp_t, int, unsigned long *, struct bio_set
extern void bvec_free_bs(struct bio_set *, struct bio_vec *, unsigned int);
extern unsigned int bvec_nr_vecs(unsigned short idx);
#ifdef CONFIG_BLK_CGROUP
int bio_associate_current(struct bio *bio);
void bio_disassociate_task(struct bio *bio);
#else /* CONFIG_BLK_CGROUP */
static inline int bio_associate_current(struct bio *bio) { return -ENOENT; }
static inline void bio_disassociate_task(struct bio *bio) { }
#endif /* CONFIG_BLK_CGROUP */
/*
* bio_set is used to allow other portions of the IO system to
* allocate their own private memory pools for bio and iovec structures.
......
include/linux/blk_types.h
View file @ 0d167518
......@@ -14,6 +14,8 @@ struct bio;
struct bio_integrity_payload;
struct page;
struct block_device;
struct io_context;
struct cgroup_subsys_state;
typedef void (bio_end_io_t) (struct bio *, int);
typedef void (bio_destructor_t) (struct bio *);
......@@ -66,6 +68,14 @@ struct bio {
bio_end_io_t *bi_end_io;
void *bi_private;
#ifdef CONFIG_BLK_CGROUP
/*
* Optional ioc and css associated with this bio. Put on bio
* release. Read comment on top of bio_associate_current().
*/
struct io_context *bi_ioc;
struct cgroup_subsys_state *bi_css;
#endif
#if defined(CONFIG_BLK_DEV_INTEGRITY)
struct bio_integrity_payload *bi_integrity; /* data integrity */
#endif
......
include/linux/blkdev.h
View file @ 0d167518
......@@ -32,10 +32,17 @@ struct blk_trace;
struct request;
struct sg_io_hdr;
struct bsg_job;
struct blkcg_gq;
#define BLKDEV_MIN_RQ 4
#define BLKDEV_MAX_RQ 128 /* Default maximum */
/*
* Maximum number of blkcg policies allowed to be registered concurrently.
* Defined here to simplify include dependency.
*/
#define BLKCG_MAX_POLS 2
struct request;
typedef void (rq_end_io_fn)(struct request *, int);
......@@ -363,6 +370,11 @@ struct request_queue {
struct list_head timeout_list;
struct list_head icq_list;
#ifdef CONFIG_BLK_CGROUP
DECLARE_BITMAP (blkcg_pols, BLKCG_MAX_POLS);
struct blkcg_gq *root_blkg;
struct list_head blkg_list;
#endif
struct queue_limits limits;
......@@ -390,12 +402,17 @@ struct request_queue {
struct mutex sysfs_lock;
int bypass_depth;
#if defined(CONFIG_BLK_DEV_BSG)
bsg_job_fn *bsg_job_fn;
int bsg_job_size;
struct bsg_class_device bsg_dev;
#endif
#ifdef CONFIG_BLK_CGROUP
struct list_head all_q_node;
#endif
#ifdef CONFIG_BLK_DEV_THROTTLING
/* Throttle data */
struct throtl_data *td;
......@@ -407,7 +424,7 @@ struct request_queue {
#define QUEUE_FLAG_SYNCFULL 3 /* read queue has been filled */
#define QUEUE_FLAG_ASYNCFULL 4 /* write queue has been filled */
#define QUEUE_FLAG_DEAD 5 /* queue being torn down */
#define QUEUE_FLAG_ELVSWITCH 6 /* don't use elevator, just do FIFO */
#define QUEUE_FLAG_BYPASS 6 /* act as dumb FIFO queue */
#define QUEUE_FLAG_BIDI 7 /* queue supports bidi requests */
#define QUEUE_FLAG_NOMERGES 8 /* disable merge attempts */
#define QUEUE_FLAG_SAME_COMP 9 /* complete on same CPU-group */
......@@ -491,6 +508,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
#define blk_queue_tagged(q) test_bit(QUEUE_FLAG_QUEUED, &(q)->queue_flags)
#define blk_queue_stopped(q) test_bit(QUEUE_FLAG_STOPPED, &(q)->queue_flags)
#define blk_queue_dead(q) test_bit(QUEUE_FLAG_DEAD, &(q)->queue_flags)
#define blk_queue_bypass(q) test_bit(QUEUE_FLAG_BYPASS, &(q)->queue_flags)
#define blk_queue_nomerges(q) test_bit(QUEUE_FLAG_NOMERGES, &(q)->queue_flags)
#define blk_queue_noxmerges(q) \
test_bit(QUEUE_FLAG_NOXMERGES, &(q)->queue_flags)
......
include/linux/elevator.h
View file @ 0d167518
......@@ -28,12 +28,13 @@ typedef int (elevator_may_queue_fn) (struct request_queue *, int);
typedef void (elevator_init_icq_fn) (struct io_cq *);
typedef void (elevator_exit_icq_fn) (struct io_cq *);
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *, gfp_t);
typedef int (elevator_set_req_fn) (struct request_queue *, struct request *,
struct bio *, gfp_t);
typedef void (elevator_put_req_fn) (struct request *);
typedef void (elevator_activate_req_fn) (struct request_queue *, struct request *);
typedef void (elevator_deactivate_req_fn) (struct request_queue *, struct request *);
typedef void *(elevator_init_fn) (struct request_queue *);
typedef int (elevator_init_fn) (struct request_queue *);
typedef void (elevator_exit_fn) (struct elevator_queue *);
struct elevator_ops
......@@ -129,7 +130,8 @@ extern void elv_unregister_queue(struct request_queue *q);
extern int elv_may_queue(struct request_queue *, int);
extern void elv_abort_queue(struct request_queue *);
extern void elv_completed_request(struct request_queue *, struct request *);
extern int elv_set_request(struct request_queue *, struct request *, gfp_t);
extern int elv_set_request(struct request_queue *q, struct request *rq,
struct bio *bio, gfp_t gfp_mask);
extern void elv_put_request(struct request_queue *, struct request *);
extern void elv_drain_elevator(struct request_queue *);
......
include/linux/iocontext.h
View file @ 0d167518
......@@ -6,11 +6,7 @@
#include <linux/workqueue.h>
enum {
ICQ_IOPRIO_CHANGED = 1 << 0,
ICQ_CGROUP_CHANGED = 1 << 1,
ICQ_EXITED = 1 << 2,
ICQ_CHANGED_MASK = ICQ_IOPRIO_CHANGED | ICQ_CGROUP_CHANGED,
};
/*
......@@ -100,6 +96,7 @@ struct io_cq {
*/
struct io_context {
atomic_long_t refcount;
atomic_t active_ref;
atomic_t nr_tasks;
/* all the fields below are protected by this lock */
......@@ -120,29 +117,37 @@ struct io_context {
struct work_struct release_work;
};
static inline struct io_context *ioc_task_link(struct io_context *ioc)
{
/*
* if ref count is zero, don't allow sharing (ioc is going away, it's
* a race).
/**
* get_io_context_active - get active reference on ioc
* @ioc: ioc of interest
*
* Only iocs with active reference can issue new IOs. This function
* acquires an active reference on @ioc. The caller must already have an
* active reference on @ioc.
*/
if (ioc && atomic_long_inc_not_zero(&ioc->refcount)) {
atomic_inc(&ioc->nr_tasks);
return ioc;
}
static inline void get_io_context_active(struct io_context *ioc)
{
WARN_ON_ONCE(atomic_long_read(&ioc->refcount) <= 0);
WARN_ON_ONCE(atomic_read(&ioc->active_ref) <= 0);
atomic_long_inc(&ioc->refcount);
atomic_inc(&ioc->active_ref);
}
return NULL;
static inline void ioc_task_link(struct io_context *ioc)
{
get_io_context_active(ioc);
WARN_ON_ONCE(atomic_read(&ioc->nr_tasks) <= 0);
atomic_inc(&ioc->nr_tasks);
}
struct task_struct;
#ifdef CONFIG_BLOCK
void put_io_context(struct io_context *ioc);
void put_io_context_active(struct io_context *ioc);
void exit_io_context(struct task_struct *task);
struct io_context *get_task_io_context(struct task_struct *task,
gfp_t gfp_flags, int node);
void ioc_ioprio_changed(struct io_context *ioc, int ioprio);
void ioc_cgroup_changed(struct io_context *ioc);
unsigned int icq_get_changed(struct io_cq *icq);
#else
struct io_context;
static inline void put_io_context(struct io_context *ioc) { }
......
include/linux/ioprio.h
View file @ 0d167518
......@@ -42,26 +42,14 @@ enum {
};
/*
* if process has set io priority explicitly, use that. if not, convert
* the cpu scheduler nice value to an io priority
* Fallback BE priority
*/
#define IOPRIO_NORM (4)
static inline int task_ioprio(struct io_context *ioc)
{
if (ioprio_valid(ioc->ioprio))
return IOPRIO_PRIO_DATA(ioc->ioprio);
return IOPRIO_NORM;
}
static inline int task_ioprio_class(struct io_context *ioc)
{
if (ioprio_valid(ioc->ioprio))
return IOPRIO_PRIO_CLASS(ioc->ioprio);
return IOPRIO_CLASS_BE;
}
/*
* if process has set io priority explicitly, use that. if not, convert
* the cpu scheduler nice value to an io priority
*/
static inline int task_nice_ioprio(struct task_struct *task)
{
return (task_nice(task) + 20) / 5;
......
init/Kconfig
View file @ 0d167518
......@@ -803,7 +803,7 @@ config RT_GROUP_SCHED
endif #CGROUP_SCHED
config BLK_CGROUP
tristate "Block IO controller"
bool "Block IO controller"
depends on BLOCK
default n
---help---
......
kernel/fork.c
View file @ 0d167518
......@@ -976,9 +976,8 @@ static int copy_io(unsigned long clone_flags, struct task_struct *tsk)
* Share io context with parent, if CLONE_IO is set
*/
if (clone_flags & CLONE_IO) {
tsk->io_context = ioc_task_link(ioc);
if (unlikely(!tsk->io_context))
return -ENOMEM;
ioc_task_link(ioc);
tsk->io_context = ioc;
} else if (ioprio_valid(ioc->ioprio)) {
new_ioc = get_task_io_context(tsk, GFP_KERNEL, NUMA_NO_NODE);
if (unlikely(!new_ioc))
......
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