From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751306Ab1ADQSM (ORCPT ); Tue, 4 Jan 2011 11:18:12 -0500 Received: from e23smtp07.au.ibm.com ([202.81.31.140]:39184 "EHLO e23smtp07.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750994Ab1ADQSK (ORCPT ); Tue, 4 Jan 2011 11:18:10 -0500 Date: Tue, 4 Jan 2011 21:48:05 +0530 From: Balbir Singh To: Minchan Kim Cc: Andrew Morton , linux-mm , LKML , KAMEZAWA Hiroyuki , Hugh Dickins Subject: Re: [PATCH v2 0/7] Change page reference handling semantic of page cache Message-ID: <20110104161805.GE3120@balbir.in.ibm.com> Reply-To: balbir@linux.vnet.ibm.com References: MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.20 (2009-06-14) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * MinChan Kim [2011-01-03 00:44:29]: > 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. > Could you please describe any testing done, was it mostly functional? -- Three Cheers, Balbir