Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1946286AbXBPXdL (ORCPT ); Fri, 16 Feb 2007 18:33:11 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1946291AbXBPXdL (ORCPT ); Fri, 16 Feb 2007 18:33:11 -0500 Received: from gw.goop.org ([64.81.55.164]:51484 "EHLO mail.goop.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1946286AbXBPXdK (ORCPT ); Fri, 16 Feb 2007 18:33:10 -0500 Message-ID: <45D63F35.3000101@goop.org> Date: Fri, 16 Feb 2007 15:33:09 -0800 From: Jeremy Fitzhardinge User-Agent: Thunderbird 1.5.0.9 (X11/20070212) MIME-Version: 1.0 To: Christoph Lameter CC: Andi Kleen , Andrew Morton , linux-kernel@vger.kernel.org, virtualization@lists.osdl.org, xen-devel@lists.xensource.com, Chris Wright , Zachary Amsden Subject: Re: [patch 07/21] Xen-paravirt: remove ctor for pgd cache References: <20070216022449.739760547@goop.org> <20070216022531.047039320@goop.org> In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1344 Lines: 32 Christoph Lameter wrote: > On Thu, 15 Feb 2007, Jeremy Fitzhardinge wrote: > > >> Remove the ctor for the pgd cache. There's no point in having the >> cache machinery do this via an indirect call when all pgd are freed in >> the one place anyway. >> > > Great. We finally get rid of this evil ..... > > On second throughts: > > Are you sure that you understand what you are modifying? The ctor is not > called when you allocate an object but when the slab allocates it. Freeing > an object does not make the slab free it. It will hold it for the next > kmalloc. So you may just have reduced performance somewhat by addiung > additional ctor processing and possibly disturbed the preservation of > cache hot pgds. It's true I wrote this patch as a result of accidentally reading slob.c rather than slab.c, which was mostly as a result of hopeful thinking (I knew that there has been discussion about removing all the slab cache stuff, and I assumed that it had already happened). As a result I'm withdrawing this patch for now, but with any luck it will be useful at some point. J - 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/