Commit 09663c86 authored by Davidlohr Bueso's avatar Davidlohr Bueso Committed by Linus Torvalds

block/cfq: replace cfq_rb_root leftmost caching

... with the generic rbtree flavor instead. No changes
in semantics whatsoever.

Link: http://lkml.kernel.org/r/20170719014603.19029-11-dave@stgolabs.netSigned-off-by: default avatarDavidlohr Bueso <dbueso@suse.de>
Reviewed-by: default avatarJan Kara <jack@suse.cz>
Acked-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Jens Axboe <axboe@fb.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent a23ba907
...@@ -93,13 +93,12 @@ struct cfq_ttime { ...@@ -93,13 +93,12 @@ struct cfq_ttime {
* move this into the elevator for the rq sorting as well. * move this into the elevator for the rq sorting as well.
*/ */
struct cfq_rb_root { struct cfq_rb_root {
struct rb_root rb; struct rb_root_cached rb;
struct rb_node *left;
unsigned count; unsigned count;
u64 min_vdisktime; u64 min_vdisktime;
struct cfq_ttime ttime; struct cfq_ttime ttime;
}; };
#define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT, \ #define CFQ_RB_ROOT (struct cfq_rb_root) { .rb = RB_ROOT_CACHED, \
.ttime = {.last_end_request = ktime_get_ns(),},} .ttime = {.last_end_request = ktime_get_ns(),},}
/* /*
...@@ -981,10 +980,9 @@ static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime) ...@@ -981,10 +980,9 @@ static inline u64 max_vdisktime(u64 min_vdisktime, u64 vdisktime)
static void update_min_vdisktime(struct cfq_rb_root *st) static void update_min_vdisktime(struct cfq_rb_root *st)
{ {
struct cfq_group *cfqg; if (!RB_EMPTY_ROOT(&st->rb.rb_root)) {
struct cfq_group *cfqg = rb_entry_cfqg(st->rb.rb_leftmost);
if (st->left) {
cfqg = rb_entry_cfqg(st->left);
st->min_vdisktime = max_vdisktime(st->min_vdisktime, st->min_vdisktime = max_vdisktime(st->min_vdisktime,
cfqg->vdisktime); cfqg->vdisktime);
} }
...@@ -1166,46 +1164,25 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2, ...@@ -1166,46 +1164,25 @@ cfq_choose_req(struct cfq_data *cfqd, struct request *rq1, struct request *rq2,
} }
} }
/*
* The below is leftmost cache rbtree addon
*/
static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root) static struct cfq_queue *cfq_rb_first(struct cfq_rb_root *root)
{ {
/* Service tree is empty */ /* Service tree is empty */
if (!root->count) if (!root->count)
return NULL; return NULL;
if (!root->left) return rb_entry(rb_first_cached(&root->rb), struct cfq_queue, rb_node);
root->left = rb_first(&root->rb);
if (root->left)
return rb_entry(root->left, struct cfq_queue, rb_node);
return NULL;
} }
static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root) static struct cfq_group *cfq_rb_first_group(struct cfq_rb_root *root)
{ {
if (!root->left) return rb_entry_cfqg(rb_first_cached(&root->rb));
root->left = rb_first(&root->rb);
if (root->left)
return rb_entry_cfqg(root->left);
return NULL;
} }
static void rb_erase_init(struct rb_node *n, struct rb_root *root) static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
{ {
rb_erase(n, root); rb_erase_cached(n, &root->rb);
RB_CLEAR_NODE(n); RB_CLEAR_NODE(n);
}
static void cfq_rb_erase(struct rb_node *n, struct cfq_rb_root *root)
{
if (root->left == n)
root->left = NULL;
rb_erase_init(n, &root->rb);
--root->count; --root->count;
} }
...@@ -1255,11 +1232,11 @@ cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg) ...@@ -1255,11 +1232,11 @@ cfqg_key(struct cfq_rb_root *st, struct cfq_group *cfqg)
static void static void
__cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
{ {
struct rb_node **node = &st->rb.rb_node; struct rb_node **node = &st->rb.rb_root.rb_node;
struct rb_node *parent = NULL; struct rb_node *parent = NULL;
struct cfq_group *__cfqg; struct cfq_group *__cfqg;
s64 key = cfqg_key(st, cfqg); s64 key = cfqg_key(st, cfqg);
int left = 1; bool leftmost = true;
while (*node != NULL) { while (*node != NULL) {
parent = *node; parent = *node;
...@@ -1269,15 +1246,12 @@ __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg) ...@@ -1269,15 +1246,12 @@ __cfq_group_service_tree_add(struct cfq_rb_root *st, struct cfq_group *cfqg)
node = &parent->rb_left; node = &parent->rb_left;
else { else {
node = &parent->rb_right; node = &parent->rb_right;
left = 0; leftmost = false;
} }
} }
if (left)
st->left = &cfqg->rb_node;
rb_link_node(&cfqg->rb_node, parent, node); rb_link_node(&cfqg->rb_node, parent, node);
rb_insert_color(&cfqg->rb_node, &st->rb); rb_insert_color_cached(&cfqg->rb_node, &st->rb, leftmost);
} }
/* /*
...@@ -1378,7 +1352,7 @@ cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg) ...@@ -1378,7 +1352,7 @@ cfq_group_notify_queue_add(struct cfq_data *cfqd, struct cfq_group *cfqg)
* so that groups get lesser vtime based on their weights, so that * so that groups get lesser vtime based on their weights, so that
* if group does not loose all if it was not continuously backlogged. * if group does not loose all if it was not continuously backlogged.
*/ */
n = rb_last(&st->rb); n = rb_last(&st->rb.rb_root);
if (n) { if (n) {
__cfqg = rb_entry_cfqg(n); __cfqg = rb_entry_cfqg(n);
cfqg->vdisktime = __cfqg->vdisktime + cfqg->vdisktime = __cfqg->vdisktime +
...@@ -2220,14 +2194,14 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, ...@@ -2220,14 +2194,14 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_queue *__cfqq; struct cfq_queue *__cfqq;
u64 rb_key; u64 rb_key;
struct cfq_rb_root *st; struct cfq_rb_root *st;
int left; bool leftmost = true;
int new_cfqq = 1; int new_cfqq = 1;
u64 now = ktime_get_ns(); u64 now = ktime_get_ns();
st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq)); st = st_for(cfqq->cfqg, cfqq_class(cfqq), cfqq_type(cfqq));
if (cfq_class_idle(cfqq)) { if (cfq_class_idle(cfqq)) {
rb_key = CFQ_IDLE_DELAY; rb_key = CFQ_IDLE_DELAY;
parent = rb_last(&st->rb); parent = rb_last(&st->rb.rb_root);
if (parent && parent != &cfqq->rb_node) { if (parent && parent != &cfqq->rb_node) {
__cfqq = rb_entry(parent, struct cfq_queue, rb_node); __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
rb_key += __cfqq->rb_key; rb_key += __cfqq->rb_key;
...@@ -2261,10 +2235,9 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, ...@@ -2261,10 +2235,9 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
cfqq->service_tree = NULL; cfqq->service_tree = NULL;
} }
left = 1;
parent = NULL; parent = NULL;
cfqq->service_tree = st; cfqq->service_tree = st;
p = &st->rb.rb_node; p = &st->rb.rb_root.rb_node;
while (*p) { while (*p) {
parent = *p; parent = *p;
__cfqq = rb_entry(parent, struct cfq_queue, rb_node); __cfqq = rb_entry(parent, struct cfq_queue, rb_node);
...@@ -2276,16 +2249,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq, ...@@ -2276,16 +2249,13 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
p = &parent->rb_left; p = &parent->rb_left;
else { else {
p = &parent->rb_right; p = &parent->rb_right;
left = 0; leftmost = false;
} }
} }
if (left)
st->left = &cfqq->rb_node;
cfqq->rb_key = rb_key; cfqq->rb_key = rb_key;
rb_link_node(&cfqq->rb_node, parent, p); rb_link_node(&cfqq->rb_node, parent, p);
rb_insert_color(&cfqq->rb_node, &st->rb); rb_insert_color_cached(&cfqq->rb_node, &st->rb, leftmost);
st->count++; st->count++;
if (add_front || !new_cfqq) if (add_front || !new_cfqq)
return; return;
...@@ -2732,7 +2702,7 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd) ...@@ -2732,7 +2702,7 @@ static struct cfq_queue *cfq_get_next_queue(struct cfq_data *cfqd)
/* There is nothing to dispatch */ /* There is nothing to dispatch */
if (!st) if (!st)
return NULL; return NULL;
if (RB_EMPTY_ROOT(&st->rb)) if (RB_EMPTY_ROOT(&st->rb.rb_root))
return NULL; return NULL;
return cfq_rb_first(st); return cfq_rb_first(st);
} }
...@@ -3219,7 +3189,7 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd) ...@@ -3219,7 +3189,7 @@ static struct cfq_group *cfq_get_next_cfqg(struct cfq_data *cfqd)
struct cfq_rb_root *st = &cfqd->grp_service_tree; struct cfq_rb_root *st = &cfqd->grp_service_tree;
struct cfq_group *cfqg; struct cfq_group *cfqg;
if (RB_EMPTY_ROOT(&st->rb)) if (RB_EMPTY_ROOT(&st->rb.rb_root))
return NULL; return NULL;
cfqg = cfq_rb_first_group(st); cfqg = cfq_rb_first_group(st);
update_min_vdisktime(st); update_min_vdisktime(st);
......
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