Michal Hocko wrote: > On Thu 29-03-18 14:30:03, Andrew Morton wrote: > [...] > > Dumb question: if a thread has been oom-killed and then tries to > > allocate memory, should the page allocator just fail the allocation > > attempt? I suppose there are all sorts of reasons why not :( > > We give those tasks access to memory reserves to move on (see > oom_reserves_allowed) and fail allocation if reserves do not help > > if (tsk_is_oom_victim(current) && > (alloc_flags == ALLOC_OOM || > (gfp_mask & __GFP_NOMEMALLOC))) > goto nopage; > So we... > > > In which case, yes, setting a new > > PF_MEMALLOC_MAY_FAIL_IF_I_WAS_OOMKILLED around such code might be a > > tidy enough solution. It would be a bit sad to add another test in the > > hot path (should_fail_alloc_page()?), but geeze we do a lot of junk > > already. > > ... do not need this. Excuse me? But that check is after /* Reclaim has failed us, start killing things */ page = __alloc_pages_may_oom(gfp_mask, order, ac, &did_some_progress); if (page) goto got_pg; which means that tsk_is_oom_victim(current) && alloc_flags == ALLOC_OOM threads can still trigger the OOM killer as soon as the OOM reaper sets MMF_OOM_SKIP.
