From 385de35722c9a22917e7bc5e63cd83a8cffa5ecd Mon Sep 17 00:00:00 2001 From: Dean Nelson Date: Wed, 21 Mar 2012 16:34:05 -0700 Subject: [PATCH] thp: allow a hwpoisoned head page to be put back to LRU Andrea Arcangeli pointed out to me that a check in __memory_failure() which was intended to prevent THP tail pages from being checked for the absence of the PG_lru flag (something that is always the case), was also preventing THP head pages from being checked. A THP head page could actually benefit from the call to shake_page() by ending up being put back to a LRU, provided it had been waiting in a pagevec array. Andrea suggested that the "!PageTransCompound(p)" in the if-statement should be replaced by a "!PageTransTail(p)", thus allowing THP head pages to be checked and possibly shaken. Signed-off-by: Dean Nelson Cc: Jin Dongming Reviewed-by: Andrea Arcangeli Cc: Andi Kleen Cc: Hidetoshi Seto Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/page-flags.h | 20 ++++++++++++++++++++ mm/memory-failure.c | 2 +- 2 files changed, 21 insertions(+), 1 deletion(-) diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index e90a673be67e..6b25758e028e 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -414,11 +414,26 @@ static inline int PageTransHuge(struct page *page) return PageHead(page); } +/* + * PageTransCompound returns true for both transparent huge pages + * and hugetlbfs pages, so it should only be called when it's known + * that hugetlbfs pages aren't involved. + */ static inline int PageTransCompound(struct page *page) { return PageCompound(page); } +/* + * PageTransTail returns true for both transparent huge pages + * and hugetlbfs pages, so it should only be called when it's known + * that hugetlbfs pages aren't involved. + */ +static inline int PageTransTail(struct page *page) +{ + return PageTail(page); +} + #else static inline int PageTransHuge(struct page *page) @@ -430,6 +445,11 @@ static inline int PageTransCompound(struct page *page) { return 0; } + +static inline int PageTransTail(struct page *page) +{ + return 0; +} #endif #ifdef CONFIG_MMU diff --git a/mm/memory-failure.c b/mm/memory-failure.c index 56080ea36140..c22076ffdd44 100644 --- a/mm/memory-failure.c +++ b/mm/memory-failure.c @@ -1063,7 +1063,7 @@ int __memory_failure(unsigned long pfn, int trapno, int flags) * The check (unnecessarily) ignores LRU pages being isolated and * walked by the page reclaim code, however that's not a big loss. */ - if (!PageHuge(p) && !PageTransCompound(p)) { + if (!PageHuge(p) && !PageTransTail(p)) { if (!PageLRU(p)) shake_page(p, 0); if (!PageLRU(p)) { -- 2.30.2