From: Christoph Lameter <cl@linux.com>
To: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@suse.de>, Alex Thorlton <athorlton@sgi.com>,
Linux-MM <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 14/15] mm: fix TLB flush race between migration, and change_protection_range
Date: Mon, 9 Dec 2013 16:00:24 +0000 [thread overview]
Message-ID: <00000142d816866f-615798f8-74d8-401c-b35a-88aa1dbc8eb5-000000@email.amazonses.com> (raw)
In-Reply-To: <52A29278.9000609@redhat.com>
On Fri, 6 Dec 2013, Rik van Riel wrote:
> > Ok then what are you trying to fix?
>
> It would help if you had actually read the patch.
I read the patch. Please update the documentation to accurately describe
the race.
>From what I can see this race affects only huge pages and the basic issue
seems to be that huge pages do not use migration entries but directly
replace the pmd (migrate_misplaced_transhuge_page() f.e.).
That is not safe and there may be multiple other races as we add more
general functionality to huge pages. An intermediate stage is needed
that allows the clearing out of remote tlb entries before the new tlb
entry becomes visible.
Then you wont need this code anymore.
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next prev parent reply other threads:[~2013-12-09 16:00 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-12-03 8:51 [PATCH 00/14] NUMA balancing segmentation faults candidate fix on large machines Mel Gorman
2013-12-03 8:51 ` [PATCH 01/15] mm: numa: Do not batch handle PMD pages Mel Gorman
2013-12-03 8:51 ` [PATCH 02/15] mm: hugetlbfs: fix hugetlbfs optimization Mel Gorman
2013-12-03 8:51 ` [PATCH 03/15] mm: thp: give transparent hugepage code a separate copy_page Mel Gorman
2013-12-04 16:59 ` Alex Thorlton
2013-12-05 13:35 ` Mel Gorman
2013-12-03 8:51 ` [PATCH 04/15] mm: numa: Serialise parallel get_user_page against THP migration Mel Gorman
2013-12-03 23:07 ` Rik van Riel
2013-12-03 23:54 ` Mel Gorman
2013-12-03 8:51 ` [PATCH 05/15] mm: numa: Call MMU notifiers on " Mel Gorman
2013-12-03 8:51 ` [PATCH 06/15] mm: Clear pmd_numa before invalidating Mel Gorman
2013-12-03 8:51 ` [PATCH 07/15] mm: numa: Do not clear PMD during PTE update scan Mel Gorman
2013-12-03 8:51 ` [PATCH 08/15] mm: numa: Do not clear PTE for pte_numa update Mel Gorman
2013-12-03 8:51 ` [PATCH 09/15] mm: numa: Ensure anon_vma is locked to prevent parallel THP splits Mel Gorman
2013-12-03 8:51 ` [PATCH 10/15] mm: numa: Avoid unnecessary work on the failure path Mel Gorman
2013-12-03 8:51 ` [PATCH 11/15] sched: numa: Skip inaccessible VMAs Mel Gorman
2013-12-03 8:51 ` [PATCH 12/15] Clear numa on mprotect Mel Gorman
2013-12-03 8:52 ` [PATCH 13/15] mm: numa: Avoid unnecessary disruption of NUMA hinting during migration Mel Gorman
2013-12-03 8:52 ` [PATCH 14/15] mm: numa: Flush TLB if NUMA hinting faults race with PTE scan update Mel Gorman
2013-12-03 23:07 ` Rik van Riel
2013-12-03 23:46 ` Mel Gorman
2013-12-04 14:33 ` Rik van Riel
2013-12-04 16:07 ` Mel Gorman
2013-12-05 15:40 ` Rik van Riel
2013-12-05 19:54 ` Mel Gorman
2013-12-05 20:05 ` Rik van Riel
2013-12-06 9:24 ` Mel Gorman
2013-12-06 17:38 ` Alex Thorlton
2013-12-06 18:32 ` Mel Gorman
2013-12-06 19:13 ` [PATCH 14/15] mm: fix TLB flush race between migration, and change_protection_range Rik van Riel
2013-12-06 20:32 ` Christoph Lameter
2013-12-06 21:21 ` Rik van Riel
2013-12-07 0:25 ` Christoph Lameter
2013-12-07 3:14 ` Rik van Riel
2013-12-09 16:00 ` Christoph Lameter [this message]
2013-12-09 16:27 ` Mel Gorman
2013-12-09 16:59 ` Christoph Lameter
2013-12-09 21:01 ` Rik van Riel
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