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Date:   Mon,  3 Apr 2023 22:03:36 +0000
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Subject: [PATCH mm-unstable RFC 4/5] memcg: remove mem_cgroup_flush_stats_atomic()
From:   Yosry Ahmed <yosryahmed@google.com>
To:     Alexander Viro <viro@zeniv.linux.org.uk>,
        Christian Brauner <brauner@kernel.org>,
        Johannes Weiner <hannes@cmpxchg.org>,
        Michal Hocko <mhocko@kernel.org>,
        Roman Gushchin <roman.gushchin@linux.dev>,
        Shakeel Butt <shakeelb@google.com>,
        Muchun Song <songmuchun@bytedance.com>,
        Andrew Morton <akpm@linux-foundation.org>
Cc:     linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org,
        cgroups@vger.kernel.org, linux-mm@kvack.org,
        Yosry Ahmed <yosryahmed@google.com>
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Previous patches removed all callers of mem_cgroup_flush_stats_atomic().
Remove the function and simplify the code.

Signed-off-by: Yosry Ahmed <yosryahmed@google.com>
---
 include/linux/memcontrol.h |  5 -----
 mm/memcontrol.c            | 24 +++++-------------------
 2 files changed, 5 insertions(+), 24 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 222d7370134c7..00a88cf947e14 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1038,7 +1038,6 @@ static inline unsigned long lruvec_page_state_local(struct lruvec *lruvec,
 }
 
 void mem_cgroup_flush_stats(void);
-void mem_cgroup_flush_stats_atomic(void);
 void mem_cgroup_flush_stats_ratelimited(void);
 
 void __mod_memcg_lruvec_state(struct lruvec *lruvec, enum node_stat_item idx,
@@ -1537,10 +1536,6 @@ static inline void mem_cgroup_flush_stats(void)
 {
 }
 
-static inline void mem_cgroup_flush_stats_atomic(void)
-{
-}
-
 static inline void mem_cgroup_flush_stats_ratelimited(void)
 {
 }
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e7fe18c0c0ef2..33339106f1d9b 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -638,7 +638,7 @@ static inline void memcg_rstat_updated(struct mem_cgroup *memcg, int val)
 	}
 }
 
-static void do_flush_stats(bool atomic)
+static void do_flush_stats(void)
 {
 	/*
 	 * We always flush the entire tree, so concurrent flushers can just
@@ -651,30 +651,16 @@ static void do_flush_stats(bool atomic)
 
 	WRITE_ONCE(flush_next_time, jiffies_64 + 2*FLUSH_TIME);
 
-	if (atomic)
-		cgroup_rstat_flush_atomic(root_mem_cgroup->css.cgroup);
-	else
-		cgroup_rstat_flush(root_mem_cgroup->css.cgroup);
+	cgroup_rstat_flush(root_mem_cgroup->css.cgroup);
 
 	atomic_set(&stats_flush_threshold, 0);
 	atomic_set(&stats_flush_ongoing, 0);
 }
 
-static bool should_flush_stats(void)
-{
-	return atomic_read(&stats_flush_threshold) > num_online_cpus();
-}
-
 void mem_cgroup_flush_stats(void)
 {
-	if (should_flush_stats())
-		do_flush_stats(false);
-}
-
-void mem_cgroup_flush_stats_atomic(void)
-{
-	if (should_flush_stats())
-		do_flush_stats(true);
+	if (atomic_read(&stats_flush_threshold) > num_online_cpus())
+		do_flush_stats();
 }
 
 void mem_cgroup_flush_stats_ratelimited(void)
@@ -689,7 +675,7 @@ static void flush_memcg_stats_dwork(struct work_struct *w)
 	 * Always flush here so that flushing in latency-sensitive paths is
 	 * as cheap as possible.
 	 */
-	do_flush_stats(false);
+	do_flush_stats();
 	queue_delayed_work(system_unbound_wq, &stats_flush_dwork, FLUSH_TIME);
 }
 
-- 
2.40.0.348.gf938b09366-goog