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authorKonstantin Khlebnikov <khlebnikov@yandex-team.ru>2017-07-06 15:40:28 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2017-07-06 16:24:35 -0700
commit8e675f7af50747e1e9e96538e8706767e4f80e2c (patch)
tree86820a752aa265ae2c118d86415ca03eed486691
parent2262185c5b287f2758afda79c149b7cf6bee165c (diff)
mm/oom_kill: count global and memory cgroup oom kills
Show count of oom killer invocations in /proc/vmstat and count of processes killed in memory cgroup in knob "memory.events" (in memory.oom_control for v1 cgroup). Also describe difference between "oom" and "oom_kill" in memory cgroup documentation. Currently oom in memory cgroup kills tasks iff shortage has happened inside page fault. These counters helps in monitoring oom kills - for now the only way is grepping for magic words in kernel log. [akpm@linux-foundation.org: fix for mem_cgroup_count_vm_event() rename] [akpm@linux-foundation.org: fix comment, per Konstantin] Link: http://lkml.kernel.org/r/149570810989.203600.9492483715840752937.stgit@buzz Signed-off-by: Konstantin Khlebnikov <khlebnikov@yandex-team.ru> Cc: Michal Hocko <mhocko@kernel.org> Cc: Tetsuo Handa <penguin-kernel@I-love.SAKURA.ne.jp> Cc: Roman Guschin <guroan@gmail.com> Cc: David Rientjes <rientjes@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/cgroup-v2.txt20
-rw-r--r--include/linux/memcontrol.h5
-rw-r--r--include/linux/vm_event_item.h1
-rw-r--r--mm/memcontrol.c2
-rw-r--r--mm/oom_kill.c5
-rw-r--r--mm/vmstat.c1
6 files changed, 29 insertions, 5 deletions
diff --git a/Documentation/cgroup-v2.txt b/Documentation/cgroup-v2.txt
index 5ac2fbde97e6..e6101976e0f1 100644
--- a/Documentation/cgroup-v2.txt
+++ b/Documentation/cgroup-v2.txt
@@ -852,13 +852,25 @@ PAGE_SIZE multiple when read back.
The number of times the cgroup's memory usage was
about to go over the max boundary. If direct reclaim
- fails to bring it down, the OOM killer is invoked.
+ fails to bring it down, the cgroup goes to OOM state.
oom
- The number of times the OOM killer has been invoked in
- the cgroup. This may not exactly match the number of
- processes killed but should generally be close.
+ The number of time the cgroup's memory usage was
+ reached the limit and allocation was about to fail.
+
+ Depending on context result could be invocation of OOM
+ killer and retrying allocation or failing alloction.
+
+ Failed allocation in its turn could be returned into
+ userspace as -ENOMEM or siletly ignored in cases like
+ disk readahead. For now OOM in memory cgroup kills
+ tasks iff shortage has happened inside page fault.
+
+ oom_kill
+
+ The number of processes belonging to this cgroup
+ killed by any kind of OOM killer.
memory.stat
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index b2a5b1cd4e55..72d0853beb31 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -582,8 +582,11 @@ 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)) {
this_cpu_inc(memcg->stat->events[idx]);
+ if (idx == OOM_KILL)
+ cgroup_file_notify(&memcg->events_file);
+ }
rcu_read_unlock();
}
#ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/include/linux/vm_event_item.h b/include/linux/vm_event_item.h
index be3ab2d13adf..37e8d31a4632 100644
--- a/include/linux/vm_event_item.h
+++ b/include/linux/vm_event_item.h
@@ -41,6 +41,7 @@ enum vm_event_item { PGPGIN, PGPGOUT, PSWPIN, PSWPOUT,
KSWAPD_LOW_WMARK_HIT_QUICKLY, KSWAPD_HIGH_WMARK_HIT_QUICKLY,
PAGEOUTRUN, PGROTATED,
DROP_PAGECACHE, DROP_SLAB,
+ OOM_KILL,
#ifdef CONFIG_NUMA_BALANCING
NUMA_PTE_UPDATES,
NUMA_HUGE_PTE_UPDATES,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3e2f8cf85b4c..4f686fc1c5fa 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3573,6 +3573,7 @@ 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));
return 0;
}
@@ -5164,6 +5165,7 @@ static int memory_events_show(struct seq_file *m, void *v)
seq_printf(m, "high %lu\n", memcg_sum_events(memcg, MEMCG_HIGH));
seq_printf(m, "max %lu\n", memcg_sum_events(memcg, MEMCG_MAX));
seq_printf(m, "oom %lu\n", memcg_sum_events(memcg, MEMCG_OOM));
+ seq_printf(m, "oom_kill %lu\n", memcg_sum_events(memcg, OOM_KILL));
return 0;
}
diff --git a/mm/oom_kill.c b/mm/oom_kill.c
index 04c9143a8625..0e2c925e7826 100644
--- a/mm/oom_kill.c
+++ b/mm/oom_kill.c
@@ -876,6 +876,11 @@ static void oom_kill_process(struct oom_control *oc, const char *message)
/* Get a reference to safely compare mm after task_unlock(victim) */
mm = victim->mm;
mmgrab(mm);
+
+ /* Raise event before sending signal: task reaper must see this */
+ count_vm_event(OOM_KILL);
+ count_memcg_event_mm(mm, OOM_KILL);
+
/*
* We should send SIGKILL before setting TIF_MEMDIE in order to prevent
* the OOM victim from depleting the memory reserves from the user
diff --git a/mm/vmstat.c b/mm/vmstat.c
index 6dae6b240b21..46281825c710 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -1018,6 +1018,7 @@ const char * const vmstat_text[] = {
"drop_pagecache",
"drop_slab",
+ "oom_kill",
#ifdef CONFIG_NUMA_BALANCING
"numa_pte_updates",