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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