From: Adam Litke <agl@us.ibm.com>
To: Mel Gorman <mel@csn.ul.ie>
Cc: akpm@linux-foundation.org, dean@arctic.org,
linux-kernel@vger.kernel.org, wli@holomorphy.com,
dwg@au1.ibm.com, apw@shadowen.org, linux-mm@kvack.org,
andi@firstfloor.org, kenchen@google.com, abh@cray.com,
hannes@saeurebad.de
Subject: Re: [PATCH 3/3] Guarantee that COW faults for a process that called mmap(MAP_PRIVATE) on hugetlbfs will succeed
Date: Wed, 28 May 2008 13:15:34 -0500 [thread overview]
Message-ID: <1211998534.12036.63.camel@localhost.localdomain> (raw)
In-Reply-To: <20080528160024.GA19349@csn.ul.ie>
On Wed, 2008-05-28 at 17:00 +0100, Mel Gorman wrote:
> [PATCH 4/3] Fix prio tree lookup
>
> I spoke too soon. This is a fix to patch 3/3.
>
> If a child unmaps the start of the VMA, the start address is different and
> that is perfectly legimite making the BUG_ON check bogus and should be removed.
> While page cache lookups are in HPAGE_SIZE, the vma->vm_pgoff is in PAGE_SIZE
> units, not HPAGE_SIZE. The offset calculation needs to be in PAGE_SIZE units
> to find other VMAs that are mapping the same range of pages. This patch
> fixes the offset calculation and adds an explanation comment as to why it
> is different from a page cache lookup.
>
> Credit goes to Johannes Weiner for spotting the bogus BUG_ON on IRC which
> led to the discovery of the faulty offset calculation.
>
> Signed-off-by: Mel Gorman <mel@csn.ul.ie>
Acked-by: Adam Litke <agl@us.ibm.com>
--
Adam Litke - (agl at us.ibm.com)
IBM Linux Technology Center
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next prev parent reply other threads:[~2008-05-28 18:17 UTC|newest]
Thread overview: 20+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-05-27 18:50 [PATCH 0/3] Guarantee faults for processes that call mmap(MAP_PRIVATE) on hugetlbfs v4 Mel Gorman
2008-05-27 18:50 ` [PATCH 1/3] Move hugetlb_acct_memory() Mel Gorman
2008-05-28 13:37 ` Adam Litke
2008-05-27 18:51 ` [PATCH 2/3] Reserve huge pages for reliable MAP_PRIVATE hugetlbfs mappings until fork() Mel Gorman
2008-05-28 13:52 ` Adam Litke
2008-05-27 18:51 ` [PATCH 3/3] Guarantee that COW faults for a process that called mmap(MAP_PRIVATE) on hugetlbfs will succeed Mel Gorman
2008-05-28 16:00 ` Mel Gorman
2008-05-28 18:15 ` Adam Litke [this message]
2008-05-28 18:16 ` Adam Litke
2008-05-29 1:42 ` Andrew Morton
2008-05-30 16:57 ` [PATCH 0/2] hugetlb reservations v4/MAP_NORESERVE V3 cleanups Andy Whitcroft
2008-05-30 16:58 ` [PATCH 1/2] huge page private reservation review cleanups Andy Whitcroft
2008-05-30 20:29 ` Andrew Morton
2008-05-31 13:06 ` Mel Gorman
2008-05-31 12:21 ` Mel Gorman
2008-05-30 16:58 ` [PATCH 2/2] huge page MAP_NORESERVE " Andy Whitcroft
-- strict thread matches above, loose matches on Subject: below --
2008-05-20 16:28 [PATCH 0/3] Guarantee faults for processes that call mmap(MAP_PRIVATE) on hugetlbfs v3 Mel Gorman
2008-05-20 16:29 ` [PATCH 3/3] Guarantee that COW faults for a process that called mmap(MAP_PRIVATE) on hugetlbfs will succeed Mel Gorman
2008-05-07 19:38 [PATCH 0/3] Guarantee faults for processes that call mmap(MAP_PRIVATE) on hugetlbfs v2 Mel Gorman
2008-05-07 19:39 ` [PATCH 3/3] Guarantee that COW faults for a process that called mmap(MAP_PRIVATE) on hugetlbfs will succeed Mel Gorman
2008-05-14 20:55 ` Adam Litke
2008-05-16 12:15 ` Mel Gorman
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