From: Andrew Morton <akpm@linux-foundation.org>
To: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Mel Gorman <mgorman@suse.de>,
Naoya Horiguchi <nao.horiguchi@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill@shutemov.name>,
"David Rientjes" <rientjes@google.com>,
Rik van Riel <riel@redhat.com>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] mm: numa: disable change protection for vma(VM_HUGETLB)
Date: Tue, 31 Mar 2015 14:35:21 -0700 [thread overview]
Message-ID: <20150331143521.652d655e396d961410179d4d@linux-foundation.org> (raw)
In-Reply-To: <20150331014554.GA8128@hori1.linux.bs1.fc.nec.co.jp>
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?
next prev parent reply other threads:[~2015-03-31 21:35 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2015-03-30 9:40 [RFC][PATCH] mm: hugetlb: add stub-like do_hugetlb_numa() Naoya Horiguchi
2015-03-30 10:28 ` Mel Gorman
2015-03-30 10:42 ` Naoya Horiguchi
2015-03-30 11:59 ` Mel Gorman
2015-03-31 1:45 ` [PATCH] mm: numa: disable change protection for vma(VM_HUGETLB) Naoya Horiguchi
2015-03-31 21:35 ` Andrew Morton [this message]
2015-04-01 4:14 ` Naoya Horiguchi
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