The patch below does not apply to the 3.12-stable tree. If someone wants it applied there, or to any other stable or longterm tree, then please email the backport, including the original git commit id to <[email protected]>.
thanks, greg k-h ------------------ original commit in Linus's tree ------------------ >From 5a6dac3ec5f583cc8ee7bc53b5500a207c4ca433 Mon Sep 17 00:00:00 2001 From: Mel Gorman <[email protected]> Date: Wed, 18 Dec 2013 17:08:36 -0800 Subject: [PATCH] mm: numa: do not clear PMD during PTE update scan If the PMD is flushed then a parallel fault in handle_mm_fault() will enter the pmd_none and do_huge_pmd_anonymous_page() path where it'll attempt to insert a huge zero page. This is wasteful so the patch avoids clearing the PMD when setting pmd_numa. 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]> Signed-off-by: Linus Torvalds <[email protected]> diff --git a/mm/huge_memory.c b/mm/huge_memory.c index 51f069303ab9..420826efda48 100644 --- a/mm/huge_memory.c +++ b/mm/huge_memory.c @@ -1539,7 +1539,7 @@ int change_huge_pmd(struct vm_area_struct *vma, pmd_t *pmd, */ if (!is_huge_zero_page(page) && !pmd_numa(*pmd)) { - entry = pmdp_get_and_clear(mm, addr, pmd); + entry = *pmd; entry = pmd_mknuma(entry); ret = HPAGE_PMD_NR; } -- 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
