Commit 8bff9a04 authored by Yosry Ahmed's avatar Yosry Ahmed Committed by Andrew Morton

cgroup: rename cgroup_rstat_flush_"irqsafe" to "atomic"

Patch series "memcg: avoid flushing stats atomically where possible", v3.

rstat flushing is an expensive operation that scales with the number of
cpus and the number of cgroups in the system.  The purpose of this series
is to minimize the contexts where we flush stats atomically.

Patches 1 and 2 are cleanups requested during reviews of prior versions of
this series.

Patch 3 makes sure we never try to flush from within an irq context.

Patches 4 to 7 introduce separate variants of mem_cgroup_flush_stats() for
atomic and non-atomic flushing, and make sure we only flush the stats
atomically when necessary.

Patch 8 is a slightly tangential optimization that limits the work done by
rstat flushing in some scenarios.


This patch (of 8):

cgroup_rstat_flush_irqsafe() can be a confusing name.  It may read as
"irqs are disabled throughout", which is what the current implementation
does (currently under discussion [1]), but is not the intention.  The
intention is that this function is safe to call from atomic contexts. 
Name it as such.

Link: https://lkml.kernel.org/r/20230330191801.1967435-1-yosryahmed@google.com
Link: https://lkml.kernel.org/r/20230330191801.1967435-2-yosryahmed@google.comSigned-off-by: default avatarYosry Ahmed <yosryahmed@google.com>
Suggested-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarShakeel Butt <shakeelb@google.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Cc: Jens Axboe <axboe@kernel.dk>
Cc: Josef Bacik <josef@toxicpanda.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Koutný <mkoutny@suse.com>
Cc: Muchun Song <muchun.song@linux.dev>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Tejun Heo <tj@kernel.org>
Cc: Vasily Averin <vasily.averin@linux.dev>
Cc: Zefan Li <lizefan.x@bytedance.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
parent 1ba3cbf3
...@@ -692,7 +692,7 @@ static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen) ...@@ -692,7 +692,7 @@ static inline void cgroup_path_from_kernfs_id(u64 id, char *buf, size_t buflen)
*/ */
void cgroup_rstat_updated(struct cgroup *cgrp, int cpu); void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
void cgroup_rstat_flush(struct cgroup *cgrp); void cgroup_rstat_flush(struct cgroup *cgrp);
void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp); void cgroup_rstat_flush_atomic(struct cgroup *cgrp);
void cgroup_rstat_flush_hold(struct cgroup *cgrp); void cgroup_rstat_flush_hold(struct cgroup *cgrp);
void cgroup_rstat_flush_release(void); void cgroup_rstat_flush_release(void);
......
...@@ -241,12 +241,12 @@ __bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp) ...@@ -241,12 +241,12 @@ __bpf_kfunc void cgroup_rstat_flush(struct cgroup *cgrp)
} }
/** /**
* cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush() * cgroup_rstat_flush_atomic- atomic version of cgroup_rstat_flush()
* @cgrp: target cgroup * @cgrp: target cgroup
* *
* This function can be called from any context. * This function can be called from any context.
*/ */
void cgroup_rstat_flush_irqsafe(struct cgroup *cgrp) void cgroup_rstat_flush_atomic(struct cgroup *cgrp)
{ {
unsigned long flags; unsigned long flags;
......
...@@ -643,7 +643,7 @@ static void __mem_cgroup_flush_stats(void) ...@@ -643,7 +643,7 @@ static void __mem_cgroup_flush_stats(void)
return; return;
flush_next_time = jiffies_64 + 2*FLUSH_TIME; flush_next_time = jiffies_64 + 2*FLUSH_TIME;
cgroup_rstat_flush_irqsafe(root_mem_cgroup->css.cgroup); cgroup_rstat_flush_atomic(root_mem_cgroup->css.cgroup);
atomic_set(&stats_flush_threshold, 0); atomic_set(&stats_flush_threshold, 0);
spin_unlock_irqrestore(&stats_flush_lock, flag); spin_unlock_irqrestore(&stats_flush_lock, flag);
} }
......
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment