Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932188AbWC3MNB (ORCPT ); Thu, 30 Mar 2006 07:13:01 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S932189AbWC3MNB (ORCPT ); Thu, 30 Mar 2006 07:13:01 -0500 Received: from mx2.mail.elte.hu ([157.181.151.9]:41396 "EHLO mx2.mail.elte.hu") by vger.kernel.org with ESMTP id S932188AbWC3MNA (ORCPT ); Thu, 30 Mar 2006 07:13:00 -0500 Date: Thu, 30 Mar 2006 14:10:30 +0200 From: Ingo Molnar To: Jens Axboe Cc: linux-kernel@vger.kernel.org, akpm@osdl.org, torvalds@osdl.org Subject: Re: [PATCH] splice support #2 Message-ID: <20060330121030.GA14621@elte.hu> References: <20060330100630.GT13476@suse.de> <20060330120055.GA10402@elte.hu> <20060330120512.GX13476@suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20060330120512.GX13476@suse.de> User-Agent: Mutt/1.4.2.1i X-ELTE-SpamScore: -2.6 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-2.6 required=5.9 tests=ALL_TRUSTED,AWL,BAYES_50 autolearn=no SpamAssassin version=3.0.3 -3.3 ALL_TRUSTED Did not pass through any untrusted hosts 0.0 BAYES_50 BODY: Bayesian spam probability is 40 to 60% [score: 0.5000] 0.7 AWL AWL: From: address is in the auto white-list X-ELTE-VirusStatus: clean Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1837 Lines: 42 * Jens Axboe wrote: > On Thu, Mar 30 2006, Ingo Molnar wrote: > > > > * Jens Axboe wrote: > > > > > Hi, > > > > > > This patch should resolve all issues mentioned so far. I'd still like > > > to implement the page moving, but that should just be a separate > > > patch. > > > > neat stuff. One question: why do we require fdin or fdout to be a pipe? > > Is there any fundamental problem with implementing what Larry's original > > paper described too: straight pagecache -> socket transfers? Without a > > pipe intermediary forced inbetween. It only adds unnecessary overhead. > > No, not a fundamental problem. I think I even hid that in some comment > in there, at least if it's decipharable by someone else than myself... > Basically I think it would be nice in the future to tidy this a little > bit and separate the actual container from the pipe itself - and have > the pipe just fill/use the same container. why is there a container needed at all? If i splice pagecache->socket, we can use sendpage to send it off immediately. There is no need for any container - both the pagecache and sendpage use struct page, and when we iterate to create a container we might as well ->sendpage() those pages off immediately instead. I agree with the purpose of making sys_splice() generic and in particular usable in scripts/shells where pipes are commonly used, but we should also fulfill the original promise (outlined 15 years ago or so) and not limit this to pipes. That way i could improve TUX to make use of it for example ;) Ingo - 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/