From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail190.messagelabs.com (mail190.messagelabs.com [216.82.249.51]) by kanga.kvack.org (Postfix) with ESMTP id 9CC3C6B0087 for ; Thu, 6 Jan 2011 05:31:39 -0500 (EST) Date: Thu, 6 Jan 2011 10:31:16 +0000 From: Mel Gorman Subject: Re: [PATCH 0/7] Change page reference handling semantic of page cache Message-ID: <20110106103116.GD29257@csn.ul.ie> References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org To: Minchan Kim Cc: Andrew Morton , linux-mm , LKML , KAMEZAWA Hiroyuki List-ID: On Thu, Dec 23, 2010 at 12:32:42AM +0900, Minchan Kim wrote: > Now we increases page reference on add_to_page_cache but doesn't decrease it > in remove_from_page_cache. Such asymmetric makes confusing about > page reference so that caller should notice it and comment why they > release page reference. It's not good API. > > Long time ago, Hugh tried it[1] but gave up of reason which > reiser4's drop_page had to unlock the page between removing it from > page cache and doing the page_cache_release. But now the situation is > changed. I think at least things in current mainline doesn't have any > obstacles. The problem is fs or somethings out of mainline. > If it has done such thing like reiser4, this patch could be a problem but > they found it when compile time since we remove remove_from_page_cache. > > [1] http://lkml.org/lkml/2004/10/24/140 > > The series configuration is following as. > > [1/7] : This patch introduces new API delete_from_page_cache. > [2,3,4,5/7] : Change remove_from_page_cache with delete_from_page_cache. > Intentionally I divide patch per file since someone might have a concern > about releasing page reference of delete_from_page_cache in > somecase (ex, truncate.c) > [6/7] : Remove old API so out of fs can meet compile error when build time > and can notice it. > [7/7] : Change __remove_from_page_cache with __delete_from_page_cache, too. > In this time, I made all-in-one patch because it doesn't change old behavior > so it has no concern. Just clean up patch. > Other than hugetlbfs being called tlbfs in patch 3/7; Acked-by: Mel Gorman -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org