Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755136AbaFYK7i (ORCPT ); Wed, 25 Jun 2014 06:59:38 -0400 Received: from e23smtp05.au.ibm.com ([202.81.31.147]:46710 "EHLO e23smtp05.au.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753055AbaFYK7g (ORCPT ); Wed, 25 Jun 2014 06:59:36 -0400 Message-ID: <53AAAB30.8080505@linux.vnet.ibm.com> Date: Wed, 25 Jun 2014 16:27:52 +0530 From: "Srivatsa S. Bhat" User-Agent: Mozilla/5.0 (X11; Linux i686 on x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.5.0 MIME-Version: 1.0 To: Peter Zijlstra CC: Stephen Warren , Frederic Weisbecker , LKML , Andrew Morton , Eric Dumazet , Ingo Molnar , Kevin Hilman , "Paul E. McKenney" , Thomas Gleixner , Viresh Kumar , "linux-next@vger.kernel.org" Subject: Re: [PATCH 2/6] irq_work: Implement remote queueing References: <1402413309-3415-1-git-send-email-fweisbec@gmail.com> <1402413309-3415-3-git-send-email-fweisbec@gmail.com> <53A9E0A5.5040402@wwwdotorg.org> <20140625051234.GD6758@twins.programming.kicks-ass.net> <20140625051721.GG3588@twins.programming.kicks-ass.net> <53AA6E11.1000404@linux.vnet.ibm.com> <20140625093657.GN19860@laptop.programming.kicks-ass.net> <20140625093944.GV16155@laptop.programming.kicks-ass.net> <53AA9B68.4050104@linux.vnet.ibm.com> <53AA9C43.3020903@linux.vnet.ibm.com> <20140625101915.GO19860@laptop.programming.kicks-ass.net> In-Reply-To: <20140625101915.GO19860@laptop.programming.kicks-ass.net> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit X-TM-AS-MML: disable X-Content-Scanned: Fidelis XPS MAILER x-cbid: 14062510-1396-0000-0000-0000051A4654 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 06/25/2014 03:49 PM, Peter Zijlstra wrote: > On Wed, Jun 25, 2014 at 03:24:11PM +0530, Srivatsa S. Bhat wrote: >> Wait, that was a stupid idea. hotplug_cfd() already invokes irq_work_run >> indirectly via flush_smp_call_function_queue(). So irq_work_cpu_notify() >> doesn't need to invoke it again, AFAIU. So perhaps we can get rid of >> irq_work_cpu_notify() altogether? > > Just so... > > getting up at 6am and sitting in an airport terminal doesn't seem to > agree with me; Haha :-) > any more silly fail here? > A few minor nits below.. > --- > Subject: irq_work: Remove BUG_ON in irq_work_run() > From: Peter Zijlstra > Date: Wed Jun 25 07:13:07 CEST 2014 > > Because of a collision with 8d056c48e486 ("CPU hotplug, smp: flush any > pending IPI callbacks before CPU offline"), which ends up calling > hotplug_cfd()->flush_smp_call_function_queue()->irq_work_run(), which > is not from IRQ context. > > And since that already calls irq_work_run() from the hotplug path, > remove our entire hotplug handling. > > Cc: Frederic Weisbecker > Reported-by: Stephen Warren > Signed-off-by: Peter Zijlstra > Link: http://lkml.kernel.org/n/tip-busatzs2gvz4v62258agipuf@git.kernel.org > --- > kernel/irq_work.c | 48 +++++------------------------------------------- > 1 file changed, 5 insertions(+), 43 deletions(-) > > Index: linux-2.6/kernel/irq_work.c > =================================================================== > --- linux-2.6.orig/kernel/irq_work.c > +++ linux-2.6/kernel/irq_work.c > @@ -160,20 +160,14 @@ static void irq_work_run_list(struct lli > } > } > > -static void __irq_work_run(void) > -{ > - irq_work_run_list(&__get_cpu_var(raised_list)); > - irq_work_run_list(&__get_cpu_var(lazy_list)); > -} > - > /* > - * Run the irq_work entries on this cpu. Requires to be ran from hardirq > - * context with local IRQs disabled. > + * hotplug calls this through: > + * hotplug_cfs() -> flush_smp_call_function_queue() s/hotplug_cfs/hotplug_cfd > */ > -void irq_work_run(void) > +static void irq_work_run(void) s/static// > { > - BUG_ON(!in_irq()); > - __irq_work_run(); > + irq_work_run_list(&__get_cpu_var(raised_list)); > + irq_work_run_list(&__get_cpu_var(lazy_list)); > } > EXPORT_SYMBOL_GPL(irq_work_run); With those 2 changes, everything looks good to me. Regards, Srivatsa S. Bhat -- 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/