From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail144.messagelabs.com (mail144.messagelabs.com [216.82.254.51]) by kanga.kvack.org (Postfix) with ESMTP id CE0F26B005A for ; Wed, 12 Aug 2009 04:32:14 -0400 (EDT) From: Johannes Weiner Subject: [patch 5/5] mm: document is_page_cache_freeable() Date: Wed, 12 Aug 2009 10:32:09 +0200 Message-Id: <1250065929-17392-5-git-send-email-hannes@cmpxchg.org> In-Reply-To: <1250065929-17392-1-git-send-email-hannes@cmpxchg.org> References: <1250065929-17392-1-git-send-email-hannes@cmpxchg.org> Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: linux-mm@kvack.org, Christoph Lameter List-ID: Enlighten the reader of this code about what reference count makes a page cache page freeable. Signed-off-by: Johannes Weiner Cc: Christoph Lameter --- mm/vmscan.c | 5 +++++ 1 files changed, 5 insertions(+), 0 deletions(-) v2: describe reference holders a bit better [thanks, Christoph] diff --git a/mm/vmscan.c b/mm/vmscan.c index 4904986..5bb1055 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; } -- 1.6.4.13.ge6580 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org