From fe6bdfc8e1e131720abbe77a2eb990c94c9024cb Mon Sep 17 00:00:00 2001 From: Roman Gushchin Date: Thu, 14 Jun 2018 15:28:05 -0700 Subject: [PATCH] mm: fix oom_kill event handling Commit e27be240df53 ("mm: memcg: make sure memory.events is uptodate when waking pollers") converted most of memcg event counters to per-memcg atomics, which made them less confusing for a user. The "oom_kill" counter remained untouched, so now it behaves differently than other counters (including "oom"). This adds nothing but confusion. Let's fix this by adding the MEMCG_OOM_KILL event, and follow the MEMCG_OOM approach. This also removes a hack from count_memcg_event_mm(), introduced earlier specially for the OOM_KILL counter. [akpm@linux-foundation.org: fix for droppage of memcg-replace-mm-owner-with-mm-memcg.patch] Link: http://lkml.kernel.org/r/20180508124637.29984-1-guro@fb.com Signed-off-by: Roman Gushchin Acked-by: Konstantin Khlebnikov Acked-by: Johannes Weiner Acked-by: Michal Hocko Cc: Vladimir Davydov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/memcontrol.h | 26 ++++++++++++++++++++++---- mm/memcontrol.c | 6 ++++-- mm/oom_kill.c | 2 +- 3 files changed, 27 insertions(+), 7 deletions(-) diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h index 4f52ec755725..6c6fb116e925 100644 --- a/include/linux/memcontrol.h +++ b/include/linux/memcontrol.h @@ -53,6 +53,7 @@ enum memcg_memory_event { MEMCG_HIGH, MEMCG_MAX, MEMCG_OOM, + MEMCG_OOM_KILL, MEMCG_SWAP_MAX, MEMCG_SWAP_FAIL, MEMCG_NR_MEMORY_EVENTS, @@ -720,11 +721,8 @@ static inline void count_memcg_event_mm(struct mm_struct *mm, rcu_read_lock(); memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); - if (likely(memcg)) { + if (likely(memcg)) count_memcg_events(memcg, idx, 1); - if (idx == OOM_KILL) - cgroup_file_notify(&memcg->events_file); - } rcu_read_unlock(); } @@ -735,6 +733,21 @@ static inline void memcg_memory_event(struct mem_cgroup *memcg, cgroup_file_notify(&memcg->events_file); } +static inline void memcg_memory_event_mm(struct mm_struct *mm, + enum memcg_memory_event event) +{ + struct mem_cgroup *memcg; + + if (mem_cgroup_disabled()) + return; + + rcu_read_lock(); + memcg = mem_cgroup_from_task(rcu_dereference(mm->owner)); + if (likely(memcg)) + memcg_memory_event(memcg, event); + rcu_read_unlock(); +} + #ifdef CONFIG_TRANSPARENT_HUGEPAGE void mem_cgroup_split_huge_fixup(struct page *head); #endif @@ -756,6 +769,11 @@ static inline void memcg_memory_event(struct mem_cgroup *memcg, { } +static inline void memcg_memory_event_mm(struct mm_struct *mm, + enum memcg_memory_event event) +{ +} + static inline enum mem_cgroup_protection mem_cgroup_protected( struct mem_cgroup *root, struct mem_cgroup *memcg) { diff --git a/mm/memcontrol.c b/mm/memcontrol.c index 5a3873e9d657..e6f0d5ef320a 100644 --- a/mm/memcontrol.c +++ b/mm/memcontrol.c @@ -3550,7 +3550,8 @@ static int mem_cgroup_oom_control_read(struct seq_file *sf, void *v) seq_printf(sf, "oom_kill_disable %d\n", memcg->oom_kill_disable); seq_printf(sf, "under_oom %d\n", (bool)memcg->under_oom); - seq_printf(sf, "oom_kill %lu\n", memcg_sum_events(memcg, OOM_KILL)); + seq_printf(sf, "oom_kill %lu\n", + atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); return 0; } @@ -5239,7 +5240,8 @@ static int memory_events_show(struct seq_file *m, void *v) atomic_long_read(&memcg->memory_events[MEMCG_MAX])); seq_printf(m, "oom %lu\n", atomic_long_read(&memcg->memory_events[MEMCG_OOM])); - seq_printf(m, "oom_kill %lu\n", memcg_sum_events(memcg, OOM_KILL)); + seq_printf(m, "oom_kill %lu\n", + atomic_long_read(&memcg->memory_events[MEMCG_OOM_KILL])); return 0; } diff --git a/mm/oom_kill.c b/mm/oom_kill.c index 6694348b27e9..84081e77bc51 100644 --- a/mm/oom_kill.c +++ b/mm/oom_kill.c @@ -913,7 +913,7 @@ static void oom_kill_process(struct oom_control *oc, const char *message) /* Raise event before sending signal: task reaper must see this */ count_vm_event(OOM_KILL); - count_memcg_event_mm(mm, OOM_KILL); + memcg_memory_event_mm(mm, MEMCG_OOM_KILL); /* * We should send SIGKILL before granting access to memory reserves -- 2.30.2