From: Mel Gorman Date: Fri, 20 May 2016 00:14:38 +0000 (-0700) Subject: mm, page_alloc: don't duplicate code in free_pcp_prepare X-Git-Tag: v4.7-rc1~110^2~2 X-Git-Url: http://git.cascardo.eti.br/?a=commitdiff_plain;h=e2769dbdc51f1baa1908ecf6c84d50f19577e1db;p=cascardo%2Flinux.git mm, page_alloc: don't duplicate code in free_pcp_prepare 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. [akpm@linux-foundation.org: fix build] Signed-off-by: Vlastimil Babka Signed-off-by: Mel Gorman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- diff --git a/mm/page_alloc.c b/mm/page_alloc.c index 193ed34a2780..7d8f642c498d 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -991,47 +991,77 @@ out: return ret; } -static bool free_pages_prepare(struct page *page, unsigned int order); - -#ifdef CONFIG_DEBUG_VM -static inline bool free_pcp_prepare(struct page *page) +static __always_inline bool free_pages_prepare(struct page *page, + unsigned int order, bool check_free) { - return free_pages_prepare(page, 0); -} + int bad = 0; -static inline bool bulkfree_pcp_prepare(struct page *page) -{ - return false; -} -#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); + trace_mm_page_free(page, order); + kmemcheck_free_shadow(page, order); + kasan_free_pages(page, order); + + /* + * Check tail pages before head page information is cleared to + * avoid checking PageCompound for order-0 pages. + */ + if (unlikely(order)) { + bool compound = PageCompound(page); + int i; + + VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); + for (i = 1; i < (1 << order); i++) { + if (compound) + bad += free_tail_pages_check(page, page + i); + if (unlikely(free_pages_check(page + i))) { + bad++; + continue; + } + (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; + } + } if (PageAnonHead(page)) page->mapping = NULL; + if (check_free) + bad += free_pages_check(page); + if (bad) + return false; - reset_page_owner(page, 0); + page_cpupid_reset_last(page); + page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; + reset_page_owner(page, order); if (!PageHighMem(page)) { debug_check_no_locks_freed(page_address(page), - PAGE_SIZE); + PAGE_SIZE << order); debug_check_no_obj_freed(page_address(page), - PAGE_SIZE); + PAGE_SIZE << order); } - arch_free_page(page, 0); - kernel_poison_pages(page, 0, 0); - kernel_map_pages(page, 0, 0); + arch_free_page(page, order); + kernel_poison_pages(page, 1 << order, 0); + kernel_map_pages(page, 1 << order, 0); - page_cpupid_reset_last(page); - page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; return true; } +#ifdef CONFIG_DEBUG_VM +static inline bool free_pcp_prepare(struct page *page) +{ + return free_pages_prepare(page, 0, true); +} + +static inline bool bulkfree_pcp_prepare(struct page *page) +{ + return false; +} +#else +static bool free_pcp_prepare(struct page *page) +{ + return free_pages_prepare(page, 0, false); +} + static bool bulkfree_pcp_prepare(struct page *page) { return free_pages_check(page); @@ -1201,66 +1231,13 @@ void __meminit reserve_bootmem_region(unsigned long start, unsigned long end) } } -static bool free_pages_prepare(struct page *page, unsigned int order) -{ - int bad = 0; - - VM_BUG_ON_PAGE(PageTail(page), page); - - trace_mm_page_free(page, order); - kmemcheck_free_shadow(page, order); - kasan_free_pages(page, order); - - /* - * Check tail pages before head page information is cleared to - * avoid checking PageCompound for order-0 pages. - */ - if (unlikely(order)) { - bool compound = PageCompound(page); - int i; - - VM_BUG_ON_PAGE(compound && compound_order(page) != order, page); - - for (i = 1; i < (1 << order); i++) { - if (compound) - bad += free_tail_pages_check(page, page + i); - if (unlikely(free_pages_check(page + i))) { - bad++; - continue; - } - (page + i)->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; - } - } - if (PageAnonHead(page)) - page->mapping = NULL; - bad += free_pages_check(page); - if (bad) - return false; - - page_cpupid_reset_last(page); - page->flags &= ~PAGE_FLAGS_CHECK_AT_PREP; - reset_page_owner(page, order); - - if (!PageHighMem(page)) { - debug_check_no_locks_freed(page_address(page), - PAGE_SIZE << order); - debug_check_no_obj_freed(page_address(page), - PAGE_SIZE << order); - } - arch_free_page(page, order); - kernel_poison_pages(page, 1 << order, 0); - kernel_map_pages(page, 1 << order, 0); - - return true; -} - static void __free_pages_ok(struct page *page, unsigned int order) { unsigned long flags; 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);