From 832fc1de01aea28255cb11d270679b7f1273f0d7 Mon Sep 17 00:00:00 2001 From: Naoya Horiguchi Date: Thu, 17 Mar 2016 14:17:41 -0700 Subject: [PATCH] /proc/kpageflags: return KPF_BUDDY for "tail" buddy pages Currently /proc/kpageflags returns nothing for "tail" buddy pages, which is inconvenient when grasping how free pages are distributed. This patch sets KPF_BUDDY for such pages. With this patch: $ grep MemFree /proc/meminfo ; tools/vm/page-types -b buddy MemFree: 3134992 kB flags page-count MB symbolic-flags long-symbolic-flags 0x0000000000000400 779272 3044 __________B_______________________________ buddy 0x0000000000000c00 4385 17 __________BM______________________________ buddy,mmap total 783657 3061 783657 pages is 3134628 kB (roughly consistent with the global counter,) so it's OK. [akpm@linux-foundation.org: update comment, per Naoya] Signed-off-by: Naoya Horiguchi Reviewed-by: Vladimir Davydov > Cc: Konstantin Khlebnikov Cc: Naoya Horiguchi Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- fs/proc/page.c | 6 ++++-- include/linux/page-flags.h | 2 ++ mm/internal.h | 3 --- mm/page_alloc.c | 2 -- 4 files changed, 6 insertions(+), 7 deletions(-) diff --git a/fs/proc/page.c b/fs/proc/page.c index b2855eea5405..0be626d85331 100644 --- a/fs/proc/page.c +++ b/fs/proc/page.c @@ -103,9 +103,9 @@ u64 stable_page_flags(struct page *page) * pseudo flags for the well known (anonymous) memory mapped pages * * Note that page->_mapcount is overloaded in SLOB/SLUB/SLQB, so the - * simple test in page_mapcount() is not enough. + * simple test in page_mapped() is not enough. */ - if (!PageSlab(page) && page_mapcount(page)) + if (!PageSlab(page) && page_mapped(page)) u |= 1 << KPF_MMAP; if (PageAnon(page)) u |= 1 << KPF_ANON; @@ -148,6 +148,8 @@ u64 stable_page_flags(struct page *page) */ if (PageBuddy(page)) u |= 1 << KPF_BUDDY; + else if (page_count(page) == 0 && is_free_buddy_page(page)) + u |= 1 << KPF_BUDDY; if (PageBalloon(page)) u |= 1 << KPF_BALLOON; diff --git a/include/linux/page-flags.h b/include/linux/page-flags.h index 19724e6ebd26..597695523679 100644 --- a/include/linux/page-flags.h +++ b/include/linux/page-flags.h @@ -593,6 +593,8 @@ static inline void __ClearPageBuddy(struct page *page) atomic_set(&page->_mapcount, -1); } +extern bool is_free_buddy_page(struct page *page); + #define PAGE_BALLOON_MAPCOUNT_VALUE (-256) static inline int PageBalloon(struct page *page) diff --git a/mm/internal.h b/mm/internal.h index ad9400d759c8..b95952c2faec 100644 --- a/mm/internal.h +++ b/mm/internal.h @@ -148,9 +148,6 @@ extern int __isolate_free_page(struct page *page, unsigned int order); extern void __free_pages_bootmem(struct page *page, unsigned long pfn, unsigned int order); extern void prep_compound_page(struct page *page, unsigned int order); -#ifdef CONFIG_MEMORY_FAILURE -extern bool is_free_buddy_page(struct page *page); -#endif extern int user_min_free_kbytes; #if defined CONFIG_COMPACTION || defined CONFIG_CMA diff --git a/mm/page_alloc.c b/mm/page_alloc.c index c46b75d14b6f..c7332a4bc8db 100644 --- a/mm/page_alloc.c +++ b/mm/page_alloc.c @@ -7152,7 +7152,6 @@ __offline_isolated_pages(unsigned long start_pfn, unsigned long end_pfn) } #endif -#ifdef CONFIG_MEMORY_FAILURE bool is_free_buddy_page(struct page *page) { struct zone *zone = page_zone(page); @@ -7171,4 +7170,3 @@ bool is_free_buddy_page(struct page *page) return order < MAX_ORDER; } -#endif -- 2.20.1