On Wed 20-06-18 20:20:38, Tetsuo Handa wrote: > Sleeping with oom_lock held can cause AB-BA lockup bug because > __alloc_pages_may_oom() does not wait for oom_lock. Since > blocking_notifier_call_chain() in out_of_memory() might sleep, sleeping > with oom_lock held is currently an unavoidable problem. Could you be more specific about the potential deadlock? Sleeping while holding oom lock is certainly not nice but I do not see how that would result in a deadlock assuming that the sleeping context doesn't sleep on the memory allocation obviously. > As a preparation for not to sleep with oom_lock held, this patch brings > OOM notifier callbacks to outside of OOM killer, with two small behavior > changes explained below. Can we just eliminate this ugliness and remove it altogether? We do not have that many notifiers. Is there anything fundamental that would prevent us from moving them to shrinkers instead? -- Michal Hocko SUSE Labs
