Messages in this thread Patch in this message | | | Date | Tue, 31 Mar 2015 14:35:21 -0700 | From | Andrew Morton <> | Subject | Re: [PATCH] mm: numa: disable change protection for vma(VM_HUGETLB) |
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On Tue, 31 Mar 2015 01:45:55 +0000 Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> wrote:
> Currently when a process accesses to hugetlb range protected with PROTNONE, > unexpected COWs are triggered, which finally put hugetlb subsystem into > broken/uncontrollable state, where for example h->resv_huge_pages is subtracted > too much and wrapped around to a very large number, and free hugepage pool > is no longer maintainable. > > This patch simply stops changing protection for vma(VM_HUGETLB) to fix the > problem. And this also allows us to avoid useless overhead of minor faults. > > ... > > --- a/kernel/sched/fair.c > +++ b/kernel/sched/fair.c > @@ -2161,8 +2161,10 @@ void task_numa_work(struct callback_head *work) > vma = mm->mmap; > } > for (; vma; vma = vma->vm_next) { > - if (!vma_migratable(vma) || !vma_policy_mof(vma)) > + if (!vma_migratable(vma) || !vma_policy_mof(vma) || > + is_vm_hugetlb_page(vma)) { > continue; > + } > > /* > * Shared library pages mapped by multiple processes are not
Which kernel version(s) need this patch?
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