From: Minchan Kim Subject: Re: [PATCH V3 0/8] Cleancache: overview Date: Fri, 23 Jul 2010 17:17:49 +0900 Message-ID: References: <20100621231809.GA11111@ca-server1.us.oracle.com> <4C49468B.40307@vflare.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: quoted-printable Cc: Dan Magenheimer , chris.mason@oracle.com, viro@zeniv.linux.org.uk, akpm@linux-foundation.org, adilger@sun.com, tytso@mit.edu, mfasheh@suse.com, joel.becker@oracle.com, matthew@wil.cx, linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-ext4@vger.kernel.org, ocfs2-devel@oss.oracle.com, linux-mm@kvack.org, jeremy@goop.org, JBeulich@novell.com, kurt.hackel@oracle.com, npiggin@suse.de, dave.mccracken@oracle.com, riel@redhat.com, avi@redhat.com, konrad.wilk@oracle.com To: ngupta@vflare.org Return-path: In-Reply-To: <4C49468B.40307@vflare.org> Sender: owner-linux-mm@kvack.org List-Id: linux-ext4.vger.kernel.org On Fri, Jul 23, 2010 at 4:36 PM, Nitin Gupta wrote: > > 2. I think change in btrfs can be avoided by moving cleancache_get_page() > from do_mpage_reapage() to filemap_fault() and this should work for all > filesystems. See: > > handle_pte_fault() -> do_(non)linear_fault() -> __do_fault() > =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 =A0 = =A0 =A0 =A0 =A0 =A0 =A0-> vma->vm_ops->fault() > > which is defined as filemap_fault() for all filesystems. If some future > filesystem uses its own custom function (why?) then it will have to arran= ge for > call to cleancache_get_page(), if it wants this feature. filemap fault works only in case of file-backed page which is mapped but don't work not-mapped cache page. So we could miss cache page by read system call if we move it into filemap_fault. --=20 Kind regards, Minchan Kim -- 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