On Tue, 5 Oct 2021 16:52:40 +0300 Vasily Averin <vvs@xxxxxxxxxxxxx> wrote: > Huge vmalloc allocation on heavy loaded node can lead to a global > memory shortage. Task called vmalloc can have worst badness and > be selected by OOM-killer, however taken fatal signal does not > interrupt allocation cycle. Vmalloc repeat page allocaions > again and again, exacerbating the crisis and consuming the memory > freed up by another killed tasks. > > After a successful completion of the allocation procedure, a fatal > signal will be processed and task will be destroyed finally. > However it may not release the consumed memory, since the allocated > object may have a lifetime unrelated to the completed task. > In the worst case, this can lead to the host will panic > due to "Out of memory and no killable processes..." > > This patch allows OOM-killer to break vmalloc cycle, makes OOM more > effective and avoid host panic. It does not check oom condition directly, > however, and breaks page allocation cycle when fatal signal was received. > > This may trigger some hidden problems, when caller does not handle > vmalloc failures, or when rollaback after failed vmalloc calls own > vmallocs inside. However all of these scenarios are incorrect: > vmalloc does not guarantee successful allocation, it has never been called > with __GFP_NOFAIL and threfore either should not be used for any rollbacks > or should handle such errors correctly and not lead to critical > failures. > This needed a little rework due to https://lkml.kernel.org/r/20210928121040.2547407-1-chenwandun@xxxxxxxxxx. Please check and retest sometime? --- a/mm/vmalloc.c~vmalloc-back-off-when-the-current-task-is-oom-killed +++ a/mm/vmalloc.c @@ -2887,6 +2887,9 @@ vm_area_alloc_pages(gfp_t gfp, int nid, page = NULL; while (nr_allocated < nr_pages) { + if (fatal_signal_pending(current)) + break; + if (nid == NUMA_NO_NODE) page = alloc_pages(gfp, order); else _
