On Thu 18-05-17 22:57:10, Tetsuo Handa wrote: > Michal Hocko wrote: > > It is racy and it basically doesn't have any allocation context so we > > might kill a task from a different domain. So can we do this instead? > > There is a slight risk that somebody might have returned VM_FAULT_OOM > > without doing an allocation but from my quick look nobody does that > > currently. > > I can't tell whether it is safe to remove out_of_memory() from > pagefault_out_of_memory(). There are VM_FAULT_OOM users in fs/ > directory. What happens if pagefault_out_of_memory() was called as a > result of e.g. GFP_NOFS allocation failure? Then we would bypass GFP_NOFS oom protection and could trigger a premature OOM killer invocation. > Is it guaranteed that all memory allocations that might occur from > page fault event (or any action that might return VM_FAULT_OOM) > are allowed to call oom_kill_process() from out_of_memory() before > reaching pagefault_out_of_memory() ? The same applies here. > Anyway, I want > > /* Avoid allocations with no watermarks from looping endlessly */ > - if (test_thread_flag(TIF_MEMDIE)) > + if (alloc_flags == ALLOC_NO_WATERMARKS && test_thread_flag(TIF_MEMDIE)) > goto nopage; > > so that we won't see similar backtraces and memory information from both > out_of_memory() and warn_alloc(). I do not think this is an improvement and it is unrelated to the discussion here. -- Michal Hocko SUSE Labs -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
