From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1760048AbYEGV1a (ORCPT ); Wed, 7 May 2008 17:27:30 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1763664AbYEGV0z (ORCPT ); Wed, 7 May 2008 17:26:55 -0400 Received: from host36-195-149-62.serverdedicati.aruba.it ([62.149.195.36]:42371 "EHLO mx.cpushare.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757569AbYEGV0x (ORCPT ); Wed, 7 May 2008 17:26:53 -0400 Date: Wed, 7 May 2008 23:26:50 +0200 From: Andrea Arcangeli To: Linus Torvalds Cc: Andrew Morton , Christoph Lameter , Jack Steiner , Robin Holt , Nick Piggin , Peter Zijlstra , kvm-devel@lists.sourceforge.net, Kanoj Sarcar , Roland Dreier , Steve Wise , linux-kernel@vger.kernel.org, Avi Kivity , linux-mm@kvack.org, general@lists.openfabrics.org, Hugh Dickins , Rusty Russell , Anthony Liguori , Chris Wright , Marcelo Tosatti , Eric Dumazet , "Paul E. McKenney" Subject: Re: [PATCH 08 of 11] anon-vma-rwsem Message-ID: <20080507212650.GA8276@duo.random> References: <6b384bb988786aa78ef0.1210170958@duo.random> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, May 07, 2008 at 01:56:23PM -0700, Linus Torvalds wrote: > This also looks very debatable indeed. The only performance numbers quoted > are: > > > This results in f.e. the Aim9 brk performance test to got down by 10-15%. > > which just seems like a total disaster. > > The whole series looks bad, in fact. Lack of authorship, bad single-line Glad you agree. Note that the fact the whole series looks bad, is _exactly_ why I couldn't let Christoph keep going with mmu-notifier-core at the very end of his patchset. I had to move it at the top to have a chance to get the KVM and GRU requirements merged in 2.6.26. I think the spinlock->rwsem conversion is ok under config option, as you can see I complained myself to various of those patches and I'll take care they're in a mergeable state the moment I submit them. What XPMEM requires are different semantics for the methods, and we never had to do any blocking I/O during vmtruncate before, now we have to. And I don't see a problem in making the conversion from spinlock->rwsem only if CONFIG_XPMEM=y as I doubt XPMEM works on anything but ia64. Please ignore all patches but mmu-notifier-core. I regularly forward _only_ mmu-notifier-core to Andrew, that's the only one that is in merge-ready status, everything else is just so XPMEM can test and we can keep discussing it to bring it in a mergeable state like mmu-notifier-core already is.