Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756200AbaD1OSO (ORCPT ); Mon, 28 Apr 2014 10:18:14 -0400 Received: from cdptpa-outbound-snat.email.rr.com ([107.14.166.225]:33908 "EHLO cdptpa-oedge-vip.email.rr.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1752663AbaD1OSJ (ORCPT ); Mon, 28 Apr 2014 10:18:09 -0400 Date: Mon, 28 Apr 2014 10:18:05 -0400 From: Steven Rostedt To: Mike Galbraith Cc: Nicholas Mc Guire , Sebastian Andrzej Siewior , linux-rt-users , LKML , Thomas Gleixner , John Kacur Subject: Re: [ANNOUNCE] 3.14-rt1 Message-ID: <20140428101805.75032f45@gandalf.local.home> In-Reply-To: <1398676186.30930.49.camel@marge.simpson.net> References: <20140411185739.GA6644@linutronix.de> <1397918766.5436.16.camel@marge.simpson.net> <1398411635.11930.45.camel@marge.simpson.net> <1398501491.12941.5.camel@marge.simpson.net> <1398520699.28726.22.camel@marge.simpson.net> <1398661784.30930.33.camel@marge.simpson.net> <1398676186.30930.49.camel@marge.simpson.net> X-Mailer: Claws Mail 3.9.3 (GTK+ 2.24.22; x86_64-pc-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-RR-Connecting-IP: 107.14.168.130:25 X-Cloudmark-Score: 0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, 28 Apr 2014 11:09:46 +0200 Mike Galbraith wrote: > migrate_disable-pushd-down-in-atomic_dec_and_spin_lo.patch > > bug: migrate_disable() after blocking is too late. > > @@ -1028,12 +1028,12 @@ int atomic_dec_and_spin_lock(atomic_t *a > /* Subtract 1 from counter unless that drops it to 0 (ie. it was 1) */ > if (atomic_add_unless(atomic, -1, 1)) > return 0; > - migrate_disable(); > rt_spin_lock(lock); > - if (atomic_dec_and_test(atomic)) > + if (atomic_dec_and_test(atomic)){ > + migrate_disable(); Makes sense, as the CPU can go offline right after the lock is grabbed and before the migrate_disable() is called. Seems that migrate_disable() must be called before taking the lock as it is done in every other location. -- Steve > return 1; > + } > rt_spin_unlock(lock); > - migrate_enable(); > return 0; > } > EXPORT_SYMBOL(atomic_dec_and_spin_lock); > > read_lock-migrate_disable-pushdown-to-rt_read_lock.patch > > bug: ditto. > > @@ -244,8 +246,10 @@ void __lockfunc rt_read_lock(rwlock_t *r > /* > * recursive read locks succeed when current owns the lock > */ > - if (rt_mutex_owner(lock) != current) > + if (rt_mutex_owner(lock) != current) { > __rt_spin_lock(lock); > + migrate_disable(); > + } > rwlock->read_depth++; > } > > Moving that migrate_disable() up will likely fix my hotplug troubles. > I'll find out when I get back from physical torture (therapy) session. > > -Mike -- 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/