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authorNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>2016-03-17 14:17:41 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-03-17 15:09:34 -0700
commit832fc1de01aea28255cb11d270679b7f1273f0d7 (patch)
treeef020cb2a44d1fee4df1359fbb3fc11a08de733b
parent12580e4b54ba8a1b22ec977c200be0174ca42348 (diff)
downloadop-kernel-dev-832fc1de01aea28255cb11d270679b7f1273f0d7.zip
op-kernel-dev-832fc1de01aea28255cb11d270679b7f1273f0d7.tar.gz
/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 <n-horiguchi@ah.jp.nec.com> Reviewed-by: Vladimir Davydov <vdavydov@virtuozzo.com>> Cc: Konstantin Khlebnikov <koct9i@gmail.com> Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--fs/proc/page.c6
-rw-r--r--include/linux/page-flags.h2
-rw-r--r--mm/internal.h3
-rw-r--r--mm/page_alloc.c2
4 files changed, 6 insertions, 7 deletions
diff --git a/fs/proc/page.c b/fs/proc/page.c
index b2855ee..0be626d 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 19724e6..5976955 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 ad9400d..b95952c 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 c46b75d..c7332a4 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
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