Messages in this thread | | | Subject | Re: [PATCH] mm/oom_kill: count global and memory cgroup oom kills | From | Konstantin Khlebnikov <> | Date | Tue, 23 May 2017 13:32:17 +0300 |
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On 23.05.2017 10:49, David Rientjes wrote: > On Mon, 22 May 2017, Konstantin Khlebnikov wrote: > >> Nope, they are different. I think we should rephase documentation somehow >> >> low - count of reclaims below low level >> high - count of post-allocation reclaims above high level >> max - count of direct reclaims >> oom - count of failed direct reclaims >> oom_kill - count of oom killer invocations and killed processes >> > > In our kernel, we've maintained counts of oom kills per memcg for years as > part of memory.oom_control for memcg v1, but we've also found it helpful > to complement that with another count that specifies the number of > processes oom killed that were attached to that exact memcg. > > In your patch, oom_kill in memory.oom_control specifies that number of oom > events that resulted in an oom kill of a process from that hierarchy, but > not the number of processes killed from a specific memcg (the difference > between oc->memcg and mem_cgroup_from_task(victim)). Not sure if you > would also find it helpful. >
This is worth addition. Let's call it "oom_victim" for short.
It allows to locate leaky part if they are spread over sub-containers within common limit. But doesn't tell which limit caused this kill. For hierarchical limits this might be not so easy.
I think oom_kill better suits for automatic actions - restart affected hierarchy, increase limits, e.t.c. But oom_victim allows to determine container affected by global oom killer.
So, probably it's worth to merge them together and increment oom_kill by global killer for victim memcg:
if (!is_memcg_oom(oc)) { count_vm_event(OOM_KILL); mem_cgroup_count_vm_event(mm, OOM_KILL); } else mem_cgroup_event(oc->memcg, OOM_KILL);
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