From: Andrew Morton <akpm@linux-foundation.org>
To: Hillf Danton <dhillf@gmail.com>, Michal Hocko <mhocko@suse.cz>,
linux-mm@kvack.org, LKML <linux-kernel@vger.kernel.org>,
KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Subject: Re: [PATCH] mm: hugetlb: undo change to page mapcount in fault handler
Date: Tue, 10 Jan 2012 12:45:58 -0800 [thread overview]
Message-ID: <20120110124558.a7303493.akpm@linux-foundation.org> (raw)
In-Reply-To: <20120104151632.05e6b3b0.akpm@linux-foundation.org>
On Wed, 4 Jan 2012 15:16:32 -0800
Andrew Morton <akpm@linux-foundation.org> wrote:
> On Fri, 23 Dec 2011 21:00:41 +0800
> Hillf Danton <dhillf@gmail.com> wrote:
>
> > Page mapcount should be updated only if we are sure that the page ends
> > up in the page table otherwise we would leak if we couldn't COW due to
> > reservations or if idx is out of bounds.
>
> It would be much nicer if we could run vma_needs_reservation() before
> even looking up or allocating the page.
>
> And afaict the interface is set up to do that: you run
> vma_needs_reservation() before allocating the page and then
> vma_commit_reservation() afterwards.
>
> But hugetlb_no_page() and hugetlb_fault() appear to have forgotten to
> run vma_commit_reservation() altogether. Why isn't this as busted as
> it appears to be?
ping?
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next prev parent reply other threads:[~2012-01-10 20:46 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-12-22 13:36 [PATCH] mm: hugetlb: undo change to page mapcount in fault handler Hillf Danton
2011-12-22 16:36 ` Michal Hocko
2011-12-23 13:00 ` Hillf Danton
2011-12-26 7:00 ` KAMEZAWA Hiroyuki
2012-01-04 23:16 ` Andrew Morton
2012-01-10 20:45 ` Andrew Morton [this message]
2012-01-11 12:06 ` Hillf Danton
2012-01-13 23:39 ` Andrew Morton
2012-01-14 5:27 ` Hillf Danton
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