Messages in this thread Patch in this message | | | From | Vlastimil Babka <> | Subject | [PATCH 3/3] mm, page_alloc: don't duplicate code in free_pcp_prepare | Date | Wed, 27 Apr 2016 14:01:16 +0200 |
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The new free_pcp_prepare() function shares a lot of code with free_pages_prepare(), which makes this a maintenance risk when some future patch modifies only one of them. We should be able to achieve the same effect (skipping free_pages_check() from !DEBUG_VM configs) by adding a parameter to free_pages_prepare() and making it inline, so the checks (and the order != 0 parts) are eliminated from the call from free_pcp_prepare().
!DEBUG_VM: bloat-o-meter reports no difference, as my gcc was already inlining free_pages_prepare() and the elimination seems to work as expected
DEBUG_VM bloat-o-meter:
add/remove: 0/1 grow/shrink: 2/0 up/down: 1035/-778 (257) function old new delta __free_pages_ok 297 1060 +763 free_hot_cold_page 480 752 +272 free_pages_prepare 778 - -778
Here inlining didn't occur before, and added some code, but it's ok for a debug option.
Signed-off-by: Vlastimil Babka <vbabka@suse.cz> --- mm/page_alloc.c | 34 ++++++---------------------------- 1 file changed, 6 insertions(+), 28 deletions(-)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 163d08ea43f0..b23f641348ab 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -990,7 +990,8 @@ static int free_tail_pages_check(struct page *head_page, struct page *page) return ret; } -static bool free_pages_prepare(struct page *page, unsigned int order) +static __always_inline bool free_pages_prepare(struct page *page, unsigned int order, + bool check_free) { int bad = 0; @@ -1023,7 +1024,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order) } if (PageAnonHead(page)) page->mapping = NULL; - if (free_pages_check(page)) { + if (check_free && free_pages_check(page)) { bad++; } else { page_cpupid_reset_last(page); @@ -1050,7 +1051,7 @@ static bool free_pages_prepare(struct page *page, unsigned int order) #ifdef CONFIG_DEBUG_VM static inline bool free_pcp_prepare(struct page *page) { - return free_pages_prepare(page, 0); + return free_pages_prepare(page, 0, true); } static inline bool bulkfree_pcp_prepare(struct page *page) @@ -1060,30 +1061,7 @@ static inline bool bulkfree_pcp_prepare(struct page *page) #else static bool free_pcp_prepare(struct page *page) { - VM_BUG_ON_PAGE(PageTail(page), page); - - trace_mm_page_free(page, 0); - kmemcheck_free_shadow(page, 0); - kasan_free_pages(page, 0); - - if (PageAnonHead(page)) - page->mapping = NULL; - - reset_page_owner(page, 0); - - if (!PageHighMem(page)) { - debug_check_no_locks_freed(page_address(page), - PAGE_SIZE); - debug_check_no_obj_freed(page_address(page), - PAGE_SIZE); - } - arch_free_page(page, 0); - kernel_poison_pages(page, 0, 0); - kernel_map_pages(page, 0, 0); - - page_cpupid_reset_last(page); - page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; - return true; + return free_pages_prepare(page, 0, false); } static bool bulkfree_pcp_prepare(struct page *page) @@ -1260,7 +1238,7 @@ static void __free_pages_ok(struct page *page, unsigned int order) int migratetype; unsigned long pfn = page_to_pfn(page); - if (!free_pages_prepare(page, order)) + if (!free_pages_prepare(page, order, true)) return; migratetype = get_pfnblock_migratetype(page, pfn); -- 2.8.1
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