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. 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? -- Michal Hocko SUSE Labs
