From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S270986AbTHGUwd (ORCPT ); Thu, 7 Aug 2003 16:52:33 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S270988AbTHGUwd (ORCPT ); Thu, 7 Aug 2003 16:52:33 -0400 Received: from e4.ny.us.ibm.com ([32.97.182.104]:12780 "EHLO e4.ny.us.ibm.com") by vger.kernel.org with ESMTP id S270986AbTHGUw3 convert rfc822-to-8bit (ORCPT ); Thu, 7 Aug 2003 16:52:29 -0400 Content-Type: text/plain; charset=US-ASCII From: Badari Pulavarty To: Andrew Morton Subject: Re: [PATCH][2.6-mm] Readahead issues and AIO read speedup Date: Thu, 7 Aug 2003 13:41:50 -0700 User-Agent: KMail/1.4.1 Cc: suparna@in.ibm.com, linux-kernel@vger.kernel.org, linux-aio@kvack.org References: <20030807100120.GA5170@in.ibm.com> <200308071021.39816.pbadari@us.ibm.com> <20030807103930.69e497a7.akpm@osdl.org> In-Reply-To: <20030807103930.69e497a7.akpm@osdl.org> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Message-Id: <200308071341.50834.pbadari@us.ibm.com> Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org On Thursday 07 August 2003 10:39 am, Andrew Morton wrote: > Badari Pulavarty wrote: > > We should do readahead of actual pages required by the current > > read would be correct solution. (like Suparna suggested). > > I repeat: what will be the effect of this if all those pages are already in > pagecache? Hmm !! Do you think just peeking at pagecache and bailing out if nothing needed to be done, is too expensive ? Anyway, slow read code has to do this later. Doing it in readahead one more time causes significant perf. hit ? And also, do you think this is the most common case ? Thanks, Badari