Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S261794AbUDEIf7 (ORCPT ); Mon, 5 Apr 2004 04:35:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263165AbUDEIf7 (ORCPT ); Mon, 5 Apr 2004 04:35:59 -0400 Received: from mail.fh-wedel.de ([213.39.232.194]:672 "EHLO mail.fh-wedel.de") by vger.kernel.org with ESMTP id S261794AbUDEIf5 (ORCPT ); Mon, 5 Apr 2004 04:35:57 -0400 Date: Mon, 5 Apr 2004 10:35:49 +0200 From: =?iso-8859-1?Q?J=F6rn?= Engel To: Jamie Lokier Cc: "Eric W. Biederman" , Pavel Machek , mj@ucw.cz, jack@ucw.cz, "Patrick J. LoPresti" , linux-kernel@vger.kernel.org Subject: Re: [PATCH] cowlinks v2 Message-ID: <20040405083549.GD28924@wohnheim.fh-wedel.de> References: <20040329231635.GA374@elf.ucw.cz> <20040402165440.GB24861@wohnheim.fh-wedel.de> <20040402180128.GA363@elf.ucw.cz> <20040402181707.GA28112@wohnheim.fh-wedel.de> <20040402182357.GB410@elf.ucw.cz> <20040402200921.GC653@mail.shareable.org> <20040402213933.GB246@elf.ucw.cz> <20040403010425.GJ653@mail.shareable.org> <20040403194344.GA5477@mail.shareable.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20040403194344.GA5477@mail.shareable.org> User-Agent: Mutt/1.3.28i Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1084 Lines: 34 On Sat, 3 April 2004 20:43:44 +0100, Jamie Lokier wrote: > > Btw, I'm not suggesting sharing page cache entries. But I am!!! Sharing the page cache is more important to me than sharing disk space. Disk space is cheap, but increasing memory beyond 1GiB in my notebook is not and 1GiB is too little, so memory is the real constraint. And it looks like Pavel already found the solution. Whenever doing something fishy that would confuse the page cache, we 1. lock 2. invalidate page cache for all files belonging to that cow entity 3. copyfile(), write(), or whatever 4. unlock This is always possibly, because page cache for cow-files is never read-write. If it was, we would have done 1-4 before and now have a regular (non-cow) file. Did I miss something? J?rn -- Premature optimization is the root of all evil. -- Donald Knuth - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/