diff options
author | Johannes Weiner <hannes@cmpxchg.org> | 2009-09-21 20:03:00 -0400 |
---|---|---|
committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 10:17:38 -0400 |
commit | ceddc3a52d783fabbf1ba623601419b9d6337194 (patch) | |
tree | 651d0fd4d5bf2455468f90364b88f01f982d79af | |
parent | edcf4748cd56adcdf0856cc99ef108a4ea3ac7fe (diff) |
mm: document is_page_cache_freeable()
Enlighten the reader of this code about what reference count makes a page
cache page freeable.
Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
Cc: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: Christoph Lameter <cl@linux-foundation.org>
Reviewed-by: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r-- | mm/vmscan.c | 5 |
1 files changed, 5 insertions, 0 deletions
diff --git a/mm/vmscan.c b/mm/vmscan.c index f5b5f029288c..5be8107e7758 100644 --- a/mm/vmscan.c +++ b/mm/vmscan.c | |||
@@ -286,6 +286,11 @@ static inline int page_mapping_inuse(struct page *page) | |||
286 | 286 | ||
287 | static inline int is_page_cache_freeable(struct page *page) | 287 | static inline int is_page_cache_freeable(struct page *page) |
288 | { | 288 | { |
289 | /* | ||
290 | * A freeable page cache page is referenced only by the caller | ||
291 | * that isolated the page, the page cache radix tree and | ||
292 | * optional buffer heads at page->private. | ||
293 | */ | ||
289 | return page_count(page) - page_has_private(page) == 2; | 294 | return page_count(page) - page_has_private(page) == 2; |
290 | } | 295 | } |
291 | 296 | ||