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authorMel Gorman <mgorman@suse.de>2014-01-07 14:00:41 +0000
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2014-01-09 12:25:13 -0800
commit273b7205315533d9327323ad7a115d9feec943b7 (patch)
tree5eafa1cc786428cbf8e5427cf8f951bb01e1be26 /mm
parenta1dc162e3f7f0c34d66981ffbcc83a2d78bc49b9 (diff)
downloadlwn-273b7205315533d9327323ad7a115d9feec943b7.tar.gz
lwn-273b7205315533d9327323ad7a115d9feec943b7.zip
mm: numa: ensure anon_vma is locked to prevent parallel THP splits
commit c3a489cac38d43ea6dc4ac240473b44b46deecf7 upstream. 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> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'mm')
-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 5003349637f1..a458517187c4 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -1342,6 +1342,13 @@ 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.