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authorVladimir Davydov <vdavydov@virtuozzo.com>2016-07-26 15:24:18 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2016-07-26 16:19:19 -0700
commit632c0a1affd861f81abdd136c886418571e19a51 (patch)
tree583d947ff0c673e009487666e730bf854195ca4a /include/linux/mm_types.h
parent99691addb42919251dcc082a70b7a11733dfcbcc (diff)
mm: clean up non-standard page->_mapcount users
- Add a proper comment to page->_mapcount. - Introduce a macro for generating helper functions. - Place all special page->_mapcount values next to each other so that readers can see all possible values and so we don't get duplicates. Link: http://lkml.kernel.org/r/502f49000e0b63e6c62e338fac6b420bf34fb526.1464079537.git.vdavydov@virtuozzo.com Signed-off-by: Vladimir Davydov <vdavydov@virtuozzo.com> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Michal Hocko <mhocko@kernel.org> Cc: Eric Dumazet <eric.dumazet@gmail.com> Cc: Minchan Kim <minchan@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/mm_types.h')
-rw-r--r--include/linux/mm_types.h5
1 files changed, 5 insertions, 0 deletions
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index a50ad735d518..79472b22d23f 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -85,6 +85,11 @@ struct page {
/*
* Count of ptes mapped in mms, to show when
* page is mapped & limit reverse map searches.
+ *
+ * Extra information about page type may be
+ * stored here for pages that are never mapped,
+ * in which case the value MUST BE <= -2.
+ * See page-flags.h for more details.
*/
atomic_t _mapcount;