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| author | Johannes Weiner <hannes@cmpxchg.org> | 2009-09-21 17:03:00 -0700 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2009-09-22 07:17:38 -0700 |
| commit | ceddc3a52d783fabbf1ba623601419b9d6337194 (patch) | |
| tree | 651d0fd4d5bf2455468f90364b88f01f982d79af /mm/vmscan.c | |
| parent | edcf4748cd56adcdf0856cc99ef108a4ea3ac7fe (diff) | |
| download | linux-ceddc3a52d783fabbf1ba623601419b9d6337194.tar.bz2 | |
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>
Diffstat (limited to 'mm/vmscan.c')
| -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) static inline int is_page_cache_freeable(struct page *page) { + /* + * A freeable page cache page is referenced only by the caller + * that isolated the page, the page cache radix tree and + * optional buffer heads at page->private. + */ return page_count(page) - page_has_private(page) == 2; } |