From: Mel Gorman <[email protected]> Subject: 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 <[email protected]> Reviewed-by: Rik van Riel <[email protected]> Cc: Alex Thorlton <[email protected]> Cc: <[email protected]> Signed-off-by: Andrew Morton <[email protected]> --- mm/huge_memory.c | 7 +++++++ 1 file changed, 7 insertions(+) diff -puN mm/huge_memory.c~mm-numa-ensure-anon_vma-is-locked-to-prevent-parallel-thp-splits mm/huge_memory.c --- a/mm/huge_memory.c~mm-numa-ensure-anon_vma-is-locked-to-prevent-parallel-thp-splits +++ a/mm/huge_memory.c @@ -1359,6 +1359,13 @@ int do_huge_pmd_numa_page(struct mm_stru 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. _ -- To unsubscribe from this list: send the line "unsubscribe stable" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html
