From dd544141b9eb8f3c58dedc9c1dcc4803de0eed45 Mon Sep 17 00:00:00 2001 From: Vasily Averin Date: Fri, 5 Nov 2021 13:39:37 -0700 Subject: vmalloc: back off when the current task is OOM-killed 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. Link: https://lkml.kernel.org/r/83efc664-3a65-2adb-d7c4-2885784cf109@virtuozzo.com Signed-off-by: Vasily Averin Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Vladimir Davydov Cc: Tetsuo Handa Cc: Uladzislau Rezki (Sony) Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/vmalloc.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'mm/vmalloc.c') diff --git a/mm/vmalloc.c b/mm/vmalloc.c index d4770396799a..2cd23fa00a13 100644 --- a/mm/vmalloc.c +++ b/mm/vmalloc.c @@ -2871,6 +2871,9 @@ vm_area_alloc_pages(gfp_t gfp, int nid, /* High-order pages or fallback path if "bulk" fails. */ while (nr_allocated < nr_pages) { + if (fatal_signal_pending(current)) + break; + if (nid == NUMA_NO_NODE) page = alloc_pages(gfp, order); else -- cgit