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[11/14] mm: memcontrol: fix missing wakeup polling thread

Message ID 20201114065213.9dBGa4C_W%akpm@linux-foundation.org (mailing list archive)
State New, archived
Headers show
Series [01/14] mm/compaction: count pages and stop correctly during page isolation | expand

Commit Message

Andrew Morton Nov. 14, 2020, 6:52 a.m. UTC 
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: memcontrol: fix missing wakeup polling thread

When we poll the swap.events, we can miss being woken up when the swap
event occurs.  Because we didn't notify.

Link: https://lkml.kernel.org/r/20201105161936.98312-1-songmuchun@bytedance.com
Fixes: f3a53a3a1e5b ("mm, memcontrol: implement memory.swap.events")
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Reviewed-by: Shakeel Butt <shakeelb@google.com>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Yafang Shao <laoar.shao@gmail.com>
Cc: Chris Down <chris@chrisdown.name>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 include/linux/memcontrol.h |   11 +++++++++--
 1 file changed, 9 insertions(+), 2 deletions(-)
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Patch

--- a/include/linux/memcontrol.h~mm-memcontrol-fix-missing-wakeup-polling-thread
+++ a/include/linux/memcontrol.h
@@ -900,12 +900,19 @@  static inline void count_memcg_event_mm(
 static inline void memcg_memory_event(struct mem_cgroup *memcg,
 				      enum memcg_memory_event event)
 {
+	bool swap_event = event == MEMCG_SWAP_HIGH || event == MEMCG_SWAP_MAX ||
+			  event == MEMCG_SWAP_FAIL;
+
 	atomic_long_inc(&memcg->memory_events_local[event]);
-	cgroup_file_notify(&memcg->events_local_file);
+	if (!swap_event)
+		cgroup_file_notify(&memcg->events_local_file);
 
 	do {
 		atomic_long_inc(&memcg->memory_events[event]);
-		cgroup_file_notify(&memcg->events_file);
+		if (swap_event)
+			cgroup_file_notify(&memcg->swap_events_file);
+		else
+			cgroup_file_notify(&memcg->events_file);
 
 		if (!cgroup_subsys_on_dfl(memory_cgrp_subsys))
 			break;