Commit c3a489ca authored Dec 18, 2013 by Mel Gorman Committed by Linus Torvalds Dec 18, 2013

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>

parent 0c5f83c2

mm/huge_memory.c

+7 −0

Original line number	Diff line number	Diff line
		@@ -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.

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