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authorMel Gorman <mgorman@suse.de>2013-12-18 17:08:38 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2013-12-18 19:04:51 -0800
commitc3a489cac38d43ea6dc4ac240473b44b46deecf7 (patch)
tree3a9dd7e524a784904c3e05cab0586bff349c45d6
parent0c5f83c23ca703d32f930393825487257a5cde6d (diff)
mm: numa: ensure anon_vma is locked to prevent parallel THP splits
The anon_vma lock prevents parallel THP splits and any associated complexity that arises when handling splits during THP migration. This patch checks if the lock was successfully acquired and bails from THP migration if it failed for any reason. Signed-off-by: Mel Gorman <mgorman@suse.de> Reviewed-by: Rik van Riel <riel@redhat.com> Cc: Alex Thorlton <athorlton@sgi.com> Cc: <stable@vger.kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/huge_memory.c7
1 files changed, 7 insertions, 0 deletions
diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 420826efda48..dbafffa5e2ee 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1359,6 +1359,13 @@ int do_huge_pmd_numa_page(struct mm_struct *mm, struct vm_area_struct *vma,
goto out_unlock;
}
+ /* Bail if we fail to protect against THP splits for any reason */
+ if (unlikely(!anon_vma)) {
+ put_page(page);
+ page_nid = -1;
+ goto clear_pmdnuma;
+ }
+
/*
* Migrate the THP to the requested node, returns with page unlocked
* and pmd_numa cleared.