From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1030187AbXCOMj3 (ORCPT ); Thu, 15 Mar 2007 08:39:29 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1030185AbXCOMj3 (ORCPT ); Thu, 15 Mar 2007 08:39:29 -0400 Received: from agminet01.oracle.com ([141.146.126.228]:33342 "EHLO agminet01.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030187AbXCOMj2 (ORCPT ); Thu, 15 Mar 2007 08:39:28 -0400 Date: Thu, 15 Mar 2007 13:38:29 +0100 From: Jens Axboe To: Nick Piggin Cc: Andrew Morton , Linux Kernel Mailing List , Linux Memory Management List Subject: Re: [patch 2/2] splice: dont readpage Message-ID: <20070315123829.GR15400@kernel.dk> References: <20070314121440.GA926@wotan.suse.de> <20070314121543.GB926@wotan.suse.de> <20070315115454.GN15400@kernel.dk> <20070315122736.GB8321@wotan.suse.de> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20070315122736.GB8321@wotan.suse.de> X-Brightmail-Tracker: AAAAAQAAAAI= X-Whitelist: TRUE Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Mar 15 2007, Nick Piggin wrote: > On Thu, Mar 15, 2007 at 12:54:54PM +0100, Jens Axboe wrote: > > On Wed, Mar 14 2007, Nick Piggin wrote: > > > > > > Splice does not need to readpage to bring the page uptodate before writing > > > to it, because prepare_write will take care of that for us. > > > > Ah great, always good to get rid of some code. > > Yeah, it should especially make block (but not page) sized and aligned > writes into uncached files work much better, AFAIKS (won't require the > synchronous read). Yep, it's a nice improvement! Plus a cleanup. > > > Splice is also wrong to SetPageUptodate before the page is actually uptodate. > > > This results in the old uninitialised memory leak. This gets fixed as a > > > matter of course when removing the readpage logic. > > > > Leak, how? The page should still be locked all through to the copy. > > Anyway, doesn't matter since you've killed it anyway. I have applied > > this patch. > > The read side doesn't need to lock the page if it is uptodate, and doesn't. Oh, then there's definitely an issue. -- Jens Axboe