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From: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
To: Rik van Riel <riel@redhat.com>
Cc: linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andi Kleen <andi@firstfloor.org>
Subject: Re: [BUG] rmap: fix page_address_in_vma() to walk through anon_vma_chain
Date: Fri, 23 Apr 2010 11:06:32 +0900	[thread overview]
Message-ID: <20100423020632.GA7383@spritzerA.linux.bs1.fc.nec.co.jp> (raw)
In-Reply-To: <4BD0688A.7050806@redhat.com>

> However, for anonymous pages, page_address_in_vma only
> ever determined whether the page _could_ be part of the
> VMA, never whether it actually was.
>
> The function page_address_in_vma has always given
> false positives, which means all of the callers already
> check that the page is actually part of the process.

I see.

> This means we may be able to get away with not verifying
> the anon_vma at all.  After all, verifying that the VMA
> has the anon_vma mapped does not mean the VMA has this
> page...
> 
> Doing away with that check gets rid of your locking
> conundrum :)

I get it, thank you :)
I'll rewrite fix patch based on your comments.

Thanks,
Naoya Horiguchi

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  reply	other threads:[~2010-04-23  2:09 UTC|newest]

Thread overview: 6+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-04-22  5:42 Naoya Horiguchi
2010-04-22  6:03 ` Naoya Horiguchi
2010-04-22 15:17 ` Rik van Riel
2010-04-23  2:06   ` Naoya Horiguchi [this message]
2010-04-23  2:08   ` [PATCH] [BUGFIX] rmap: remove anon_vma check in page_address_in_vma() Naoya Horiguchi
2010-04-23 13:52     ` Rik van Riel

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