mm: Prevent parallel splits during THP migration
authorMel Gorman <mgorman@suse.de>
Mon, 7 Oct 2013 10:28:44 +0000 (11:28 +0100)
committerIngo Molnar <mingo@kernel.org>
Wed, 9 Oct 2013 10:39:43 +0000 (12:39 +0200)
commitb8916634b77bffb233d8f2f45703c80343457cc1
treee2452c3d74d14ef387b9cce460f3b5597eca3676
parentff9042b11a71c81238c70af168cd36b98a6d5a3c
mm: Prevent parallel splits during THP migration

THP migrations are serialised by the page lock but on its own that does
not prevent THP splits. If the page is split during THP migration then
the pmd_same checks will prevent page table corruption but the unlock page
and other fix-ups potentially will cause corruption. This patch takes the
anon_vma lock to prevent parallel splits during migration.

Signed-off-by: Mel Gorman <mgorman@suse.de>
Reviewed-by: Rik van Riel <riel@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Signed-off-by: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/1381141781-10992-7-git-send-email-mgorman@suse.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>
mm/huge_memory.c