Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755817Ab3IOLeo (ORCPT ); Sun, 15 Sep 2013 07:34:44 -0400 Received: from mail-bk0-f46.google.com ([209.85.214.46]:58866 "EHLO mail-bk0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751881Ab3IOLen (ORCPT ); Sun, 15 Sep 2013 07:34:43 -0400 Message-ID: <52359B4E.7060700@colorfullife.com> Date: Sun, 15 Sep 2013 13:34:38 +0200 From: Manfred Spraul User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130805 Thunderbird/17.0.8 MIME-Version: 1.0 To: Mike Galbraith CC: Andrew Morton , Linus Torvalds , LKML , Rik van Riel , Davidlohr Bueso , hhuang@redhat.com, Greg KH Subject: Re: [PATCH 1/2] ipc/sem.c: Race in sem_lock() References: <1379194496-4642-1-git-send-email-manfred@colorfullife.com> <1379225343.5545.154.camel@marge.simpson.net> In-Reply-To: <1379225343.5545.154.camel@marge.simpson.net> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1956 Lines: 51 Hi all, On 09/15/2013 08:09 AM, Mike Galbraith wrote: > On Sat, 2013-09-14 at 23:34 +0200, Manfred Spraul wrote: > >> The bug is probably also present in 3.10 and 3.11, but for these kernels >> is is probably simpler just to move the test of sma->complex_count after >> the spin_is_locked() test. > IMHO, your 6 patch series should go to stable as well. Scalability is > still BAD without them. Now, you've shown the lock split to be buggy. > > Logically, the whole thing should be reverted entirely in stable, or > fixed up properly. Davidlohr: Are you working on fixing the open issues? IMHO Mike is right, especially for the 3.10 long-term kernel: Either everything in ipc/*.c must be reverted or it should be fixed properly (i.e.: cherry-pick ipc/*) I have created bugzilla entries for all issues I'm aware of: https://bugzilla.kernel.org/show_bug.cgi?id=61351 I sent a patch yesterday. https://bugzilla.kernel.org/show_bug.cgi?id=61321 https://bugzilla.kernel.org/show_bug.cgi?id=61331 https://bugzilla.kernel.org/show_bug.cgi?id=61341 https://bugzilla.kernel.org/show_bug.cgi?id=61361 https://bugzilla.kernel.org/show_bug.cgi?id=61371 No patches for theses 5 bugs. And: Given these numbers from Mike, I would hate to revert anything: On 09/15/2013 10:06 AM, Mike Galbraith wrote: > On Sun, 2013-09-15 at 08:09 +0200, Mike Galbraith wrote: > >> Humongous improvements... > (a couple sem-waitzero numbers) > > master: Cpus 64, interleave 1 delay 0: 10039494796 in 30 secs > 3.10.10: Cpus 64, interleave 1 delay 0: 129236313 in 30 secs > > (rapidly scrolling micro-font bench vs reality disclaimer) One semop() completed every 3 ns, around 600 cpu ticks per operation. -- Manfred -- 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/