From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752842AbYI3Kji (ORCPT ); Tue, 30 Sep 2008 06:39:38 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751489AbYI3Kja (ORCPT ); Tue, 30 Sep 2008 06:39:30 -0400 Received: from mx2.mail.elte.hu ([157.181.151.9]:44629 "EHLO mx2.mail.elte.hu" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751446AbYI3Kj3 (ORCPT ); Tue, 30 Sep 2008 06:39:29 -0400 Date: Tue, 30 Sep 2008 12:39:06 +0200 From: Ingo Molnar To: Nick Piggin Cc: Peter Zijlstra , Eric Dumazet , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-mm@kvack.org Subject: Re: [PATCH 0/4] futex: get_user_pages_fast() for shared futexes Message-ID: <20080930103906.GF7557@elte.hu> References: <20080926173219.885155151@twins.programming.kicks-ass.net> <20080927161712.GA1525@elte.hu> <200809301721.52148.nickpiggin@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200809301721.52148.nickpiggin@yahoo.com.au> User-Agent: Mutt/1.5.18 (2008-05-17) X-ELTE-VirusStatus: clean X-ELTE-SpamScore: -1.5 X-ELTE-SpamLevel: X-ELTE-SpamCheck: no X-ELTE-SpamVersion: ELTE 2.0 X-ELTE-SpamCheck-Details: score=-1.5 required=5.9 tests=BAYES_00 autolearn=no SpamAssassin version=3.2.3 -1.5 BAYES_00 BODY: Bayesian spam probability is 0 to 1% [score: 0.0000] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org * Nick Piggin wrote: > On Sunday 28 September 2008 02:17, Ingo Molnar wrote: > > * Peter Zijlstra wrote: > > > Since get_user_pages_fast() made it in, I thought to give this another > > > try. Lightly tested by disabling the private futexes and running some > > > java proglets. > > > > hm, very interesting. Since this is an important futex usecase i started > > testing it in tip/core/futexes: > > > > cd33272: futex: cleanup fshared > > a135356: futex: use fast_gup() > > 39ce77b: futex: reduce mmap_sem usage > > 0d7a336: futex: rely on get_user_pages() for shared futexes > > > > Nick, it would be nice to get an Acked-by/Reviewed-by from you, before > > we think about whether it should go upstream. > > Yeah, these all look pretty good. It's nice to get rid of mmap sem here. > > Which reminds me, we need to put a might_lock mmap_sem into > get_user_pages_fast... > > But these patches look good to me (last time we discussed them I thought > there was a race with page truncate, but it looks like you've closed that > by holding page lock over the whole operation...) > > Nice work, Peter. great - i've added your Acked-by to the patches and have activated the tip/core/futexes branch for tip/auto-core-next linux-next integration. here are the commits: 42569c3: futex: fixup get_futex_key() for private futexes c2f9f20: futex: cleanup fshared 734b05b: futex: use fast_gup() 6127070: futex: reduce mmap_sem usage 38d47c1: futex: rely on get_user_pages() for shared futexes Thanks, Ingo