Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1759384AbXIQTe7 (ORCPT ); Mon, 17 Sep 2007 15:34:59 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1756624AbXIQTet (ORCPT ); Mon, 17 Sep 2007 15:34:49 -0400 Received: from pentafluge.infradead.org ([213.146.154.40]:33105 "EHLO pentafluge.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756363AbXIQTer (ORCPT ); Mon, 17 Sep 2007 15:34:47 -0400 Date: Mon, 17 Sep 2007 20:34:43 +0100 From: Christoph Hellwig To: Mingming Cao Cc: Christoph Hellwig , pbadari@us.ibm.com, Christoph Lameter , linux-fsdevel@vger.kernel.org, ext4 development , linux-kernel@vger.kernel.org Subject: Re: [PATCH] JBD slab cleanups Message-ID: <20070917193443.GA32013@infradead.org> Mail-Followup-To: Christoph Hellwig , Mingming Cao , pbadari@us.ibm.com, Christoph Lameter , linux-fsdevel@vger.kernel.org, ext4 development , linux-kernel@vger.kernel.org References: <1188605538.3837.51.camel@localhost.localdomain> <20070901183922.GA12907@infradead.org> <20070902152801.GA19962@infradead.org> <20070903134043.GB28962@infradead.org> <20070903193308.GA7771@infradead.org> <1189796027.3841.6.camel@localhost.localdomain> <1190057391.3845.22.camel@localhost.localdomain> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1190057391.3845.22.camel@localhost.localdomain> User-Agent: Mutt/1.4.2.3i X-SRS-Rewrite: SMTP reverse-path rewritten from by pentafluge.infradead.org See http://www.infradead.org/rpr.html Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 825 Lines: 18 On Mon, Sep 17, 2007 at 12:29:51PM -0700, Mingming Cao wrote: > The problem with this patch, as Andreas Dilger pointed today in ext4 > interlock call, for 1k,2k block size ext2/3/4, get_free_pages() waste > 1/3-1/2 page space. > > What was the originally intention to set up slabs for committed_data(and > frozen_buffer) in JBD? Why not using kmalloc? kmalloc is using slabs :) The intent was to avoid the wasted memory, but as we've repeated a gazillion times wasted memory on a rather rare codepath doesn't really matter when you just crash random storage drivers otherwise. - 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/