Messages in this thread | | | Subject | Re: [RFC PATCH] mm, oom: introduce vm.sacrifice_hugepage_on_oom | From | David Hildenbrand <> | Date | Wed, 17 Feb 2021 10:09:58 +0100 |
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On 16.02.21 04:07, Eiichi Tsukata wrote: > Hugepages can be preallocated to avoid unpredictable allocation latency. > If we run into 4k page shortage, the kernel can trigger OOM even though > there were free hugepages. When OOM is triggered by user address page > fault handler, we can use oom notifier to free hugepages in user space > but if it's triggered by memory allocation for kernel, there is no way > to synchronously handle it in user space. > > This patch introduces a new sysctl vm.sacrifice_hugepage_on_oom. If > enabled, it first tries to free a hugepage if available before invoking > the oom-killer. The default value is disabled not to change the current > behavior.
In addition to the other comments, some more thoughts:
What if you're low on kernel memory but you end up freeing huge pages residing in ZONE_MOVABLE? IOW, this is not zone aware.
-- Thanks,
David / dhildenb
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