From da838d4fcba675cbf864f225d76f970e91220ee6 Mon Sep 17 00:00:00 2001 From: Mel Gorman Date: Thu, 19 May 2016 17:14:21 -0700 Subject: [PATCH] mm, page_alloc: pull out side effects from free_pages_check Check without side-effects should be easier to maintain. It also removes the duplicated cpupid and flags reset done in !DEBUG_VM variant of both free_pcp_prepare() and then bulkfree_pcp_prepare(). Finally, it enables the next patch. It shouldn't result in new branches, thanks to inlining of the check. !DEBUG_VM bloat-o-meter: add/remove: 0/0 grow/shrink: 0/2 up/down: 0/-27 (-27) function old new delta __free_pages_ok 748 739 -9 free_pcppages_bulk 1403 1385 -18 DEBUG_VM: add/remove: 0/0 grow/shrink: 0/1 up/down: 0/-28 (-28) function old new delta free_pages_prepare 806 778 -28 This is also slightly faster because cpupid information is not set on tail pages so we can avoid resets there. Signed-off-by: Vlastimil Babka Signed-off-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- mm/page_alloc.c | 13 ++++++++----- 1 file changed, 8 insertions(+), 5 deletions(-) diff --git a/mm/page_alloc.c b/mm/page_alloc.c index d51543de1813..fea50b0cb405 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -833,11 +833,8 @@ static void free_pages_check_bad(struct page *page) static inline int free_pages_check(struct page *page) { - if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE))) { - page_cpupid_reset_last(page); - page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; + if (likely(page_expected_state(page, PAGE_FLAGS_CHECK_AT_FREE))) return 0; - } /* Something has gone sideways, find it */ free_pages_check_bad(page); @@ -1078,7 +1075,11 @@ static bool free_pages_prepare(struct page *page, unsigned int order) for (i = 1; i < (1 << order); i++) { if (compound) bad += free_tail_pages_check(page, page + i); - bad += free_pages_check(page + i); + if (unlikely(free_pages_check(page + i))) { + bad++; + continue; + } + (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; } } if (PageAnonHead(page)) @@ -1087,6 +1088,8 @@ static bool free_pages_prepare(struct page *page, unsigned int order) if (bad) return false; + page_cpupid_reset_last(page); + page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; reset_page_owner(page, order); if (!PageHighMem(page)) { -- 2.20.1