From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932328AbWGDSnc (ORCPT ); Tue, 4 Jul 2006 14:43:32 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932331AbWGDSnc (ORCPT ); Tue, 4 Jul 2006 14:43:32 -0400 Received: from rwcrmhc14.comcast.net ([216.148.227.154]:14283 "EHLO rwcrmhc14.comcast.net") by vger.kernel.org with ESMTP id S932328AbWGDSnb (ORCPT ); Tue, 4 Jul 2006 14:43:31 -0400 Message-ID: <44AAB6D4.1040101@namesys.com> Date: Tue, 04 Jul 2006 11:43:32 -0700 From: Hans Reiser User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.5) Gecko/20041217 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Pekka Enberg CC: "Vladimir V. Saveliev" , Andrew Morton , lkml , reiserfs-dev@namesys.com Subject: Re: [PATCH 1/2] batch-write.patch References: <44A42750.5020807@namesys.com> <20060629185017.8866f95e.akpm@osdl.org> <1152011576.6454.36.camel@tribesman.namesys.com> <1152012117.6454.41.camel@tribesman.namesys.com> <84144f020607040507u58489b8eqfe8f41ef0d76b369@mail.gmail.com> In-Reply-To: <84144f020607040507u58489b8eqfe8f41ef0d76b369@mail.gmail.com> X-Enigmail-Version: 0.90.1.0 X-Enigmail-Supports: pgp-inline, pgp-mime Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Pekka Enberg wrote: > On 7/4/06, Vladimir V. Saveliev wrote: > >> @@ -784,6 +786,8 @@ otherwise noted. >> >> writev: called by the writev(2) system call >> >> + batch_write: optional, if implemented called by writev(2) and >> write(2) >> + > > > It'd be nice if you added some explanation here why a filesystem > developer would want to implement it. > > Pekka > > Vladimir, it sounds like he found another place you might insert this comment: +/* + * When calling the filesystem for writes, there is processing + * that must be done: + * 1) per word + * 2) per page + * 3) per call to the FS + * If the FS is called per page, then it turns out that 3) costs more + * than 1) and 2) for sophisticated filesystems. To allow the FS to + * choose to pay the cost of 3) only once we call batch_write, if the + * FS supports it. + */ Thanks Pekka!