[merged mm-stable] cgroup-rename-cgroup_rstat_flush_irqsafe-to-atomic.patch removed from -mm tree

[merged mm-stable] cgroup-rename-cgroup_rstat_flush_irqsafe-to-atomic.patch removed from -mm tree

[Andrew Morton]

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The quilt patch titled
     Subject: cgroup: rename cgroup_rstat_flush_"irqsafe" to "atomic"
has been removed from the -mm tree.  Its filename was
     cgroup-rename-cgroup_rstat_flush_irqsafe-to-atomic.patch

This patch was dropped because it was merged into the mm-stable branch
of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

------------------------------------------------------
From: Yosry Ahmed <yosryahmed@google.com>
Subject: cgroup: rename cgroup_rstat_flush_"irqsafe" to "atomic"
Date: Thu, 30 Mar 2023 19:17:54 +0000

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.com
Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
Suggested-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Shakeel Butt <shakeelb@google.com>
Acked-by: Johannes 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: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/cgroup.h |    2 +-
 kernel/cgroup/rstat.c  |    4 ++--
 mm/memcontrol.c        |    2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

--- a/include/linux/cgroup.h~cgroup-rename-cgroup_rstat_flush_irqsafe-to-atomic
+++ a/include/linux/cgroup.h
@@ -692,7 +692,7 @@ static inline void cgroup_path_from_kern
  */
 void cgroup_rstat_updated(struct cgroup *cgrp, int cpu);
 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_release(void);
 
--- a/kernel/cgroup/rstat.c~cgroup-rename-cgroup_rstat_flush_irqsafe-to-atomic
+++ a/kernel/cgroup/rstat.c
@@ -241,12 +241,12 @@ __bpf_kfunc void cgroup_rstat_flush(stru
 }
 
 /**
- * cgroup_rstat_flush_irqsafe - irqsafe version of cgroup_rstat_flush()
+ * cgroup_rstat_flush_atomic- atomic version of cgroup_rstat_flush()
  * @cgrp: target cgroup
  *
  * 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;
 
--- a/mm/memcontrol.c~cgroup-rename-cgroup_rstat_flush_irqsafe-to-atomic
+++ a/mm/memcontrol.c
@@ -643,7 +643,7 @@ static void __mem_cgroup_flush_stats(voi
 		return;
 
 	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);
 	spin_unlock_irqrestore(&stats_flush_lock, flag);
 }
_

Patches currently in -mm which might be from yosryahmed@google.com are

memcg-rename-mem_cgroup_flush_stats_delayed-to-ratelimited.patch
memcg-do-not-flush-stats-in-irq-context.patch
memcg-replace-stats_flush_lock-with-an-atomic.patch
memcg-sleep-during-flushing-stats-in-safe-contexts.patch
workingset-memcg-sleep-when-flushing-stats-in-workingset_refault.patch
vmscan-memcg-sleep-when-flushing-stats-during-reclaim.patch
memcg-do-not-modify-rstat-tree-for-zero-updates.patch
memcg-page_cgroup_ino-get-memcg-from-the-pages-folio.patch
mm-vmscan-ignore-non-lru-based-reclaim-in-memcg-reclaim.patch
mm-vmscan-move-set_task_reclaim_state-near-flush_reclaim_state.patch
mm-vmscan-refactor-updating-current-reclaim_state.patch