Messages in this thread | | | Subject | Re: [PATCH 2/3] mm: oom: show unreclaimable slab info when kernel panic | From | "Yang Shi" <> | Date | Thu, 28 Sep 2017 01:25:50 +0800 |
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On 9/27/17 3:45 AM, Michal Hocko wrote: > On Wed 27-09-17 08:53:35, Yang Shi wrote: >> Kernel may panic when oom happens without killable process sometimes it >> is caused by huge unreclaimable slabs used by kernel. >> >> Although kdump could help debug such problem, however, kdump is not >> available on all architectures and it might be malfunction sometime. >> And, since kernel already panic it is worthy capturing such information >> in dmesg to aid touble shooting. >> >> Print out unreclaimable slab info (used size and total size) which >> actual memory usage is not zero (num_objs * size != 0) when: >> - unreclaimable slabs : all user memory > unreclaim_slabs_oom_ratio >> - panic_on_oom is set or no killable process > > OK, this is better but I do not see why this should be tunable via proc.
Just thought someone might want to dump unreclaimable slab info unconditionally.
> Can we start with simple NR_SLAB_UNRECLAIMABLE > LRU_PAGES and place it > into dump_header so that we get the report also during regular OOM Yes.
Thanks, Yang
>
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