Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755616Ab2KOD7p (ORCPT ); Wed, 14 Nov 2012 22:59:45 -0500 Received: from hrndva-omtalb.mail.rr.com ([71.74.56.122]:19568 "EHLO hrndva-omtalb.mail.rr.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755533Ab2KOD7n (ORCPT ); Wed, 14 Nov 2012 22:59:43 -0500 X-Authority-Analysis: v=2.0 cv=NLdXCjGg c=1 sm=0 a=rXTBtCOcEpjy1lPqhTCpEQ==:17 a=mNMOxpOpBa8A:10 a=dSWLLQtwMLwA:10 a=5SG0PmZfjMsA:10 a=Q9fys5e9bTEA:10 a=meVymXHHAAAA:8 a=_2UvRtBX3U8A:10 a=pGLkceISAAAA:8 a=JfrnYn6hAAAA:8 a=VwQbUJbxAAAA:8 a=Z4Rwk6OoAAAA:8 a=t7CeM3EgAAAA:8 a=D7FtBBmPhq-9Irmde2wA:9 a=PUjeQqilurYA:10 a=MSl-tDqOz04A:10 a=3Rfx1nUSh_UA:10 a=Zh68SRI7RUMA:10 a=LI9Vle30uBYA:10 a=jbrJJM5MRmoA:10 a=jeBq3FmKZ4MA:10 a=2e6ZYRoF4I4A:10 a=rXTBtCOcEpjy1lPqhTCpEQ==:117 X-Cloudmark-Score: 0 X-Originating-IP: 74.67.115.198 Message-ID: <1352951981.18025.90.camel@gandalf.local.home> Subject: Re: [PATCH 5/7] irq_work: Don't stop the tick with pending works From: Steven Rostedt To: Frederic Weisbecker Cc: Ingo Molnar , LKML , Peter Zijlstra , Thomas Gleixner , Andrew Morton , Paul Gortmaker Date: Wed, 14 Nov 2012 22:59:41 -0500 In-Reply-To: <1352925457-15700-6-git-send-email-fweisbec@gmail.com> References: <1352925457-15700-1-git-send-email-fweisbec@gmail.com> <1352925457-15700-6-git-send-email-fweisbec@gmail.com> Content-Type: text/plain; charset="ISO-8859-15" X-Mailer: Evolution 3.4.3-1 Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2885 Lines: 91 On Wed, 2012-11-14 at 21:37 +0100, Frederic Weisbecker wrote: > Don't stop the tick if we have pending irq works on the > queue, otherwise if the arch can't raise self-IPIs, we may not > find an opportunity to execute the pending works for a while. > > Signed-off-by: Frederic Weisbecker > Cc: Peter Zijlstra > Cc: Thomas Gleixner > Cc: Ingo Molnar > Cc: Andrew Morton > Cc: Steven Rostedt > Cc: Paul Gortmaker > --- > include/linux/irq_work.h | 6 ++++++ > kernel/irq_work.c | 11 +++++++++++ > kernel/time/tick-sched.c | 3 ++- > 3 files changed, 19 insertions(+), 1 deletions(-) > > diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h > index 6a9e8f5..a69704f 100644 > --- a/include/linux/irq_work.h > +++ b/include/linux/irq_work.h > @@ -20,4 +20,10 @@ bool irq_work_queue(struct irq_work *work); > void irq_work_run(void); > void irq_work_sync(struct irq_work *work); > > +#ifdef CONFIG_IRQ_WORK > +bool irq_work_needs_cpu(void); > +#else > +static bool irq_work_needs_cpu(void) { return false; } > +#endif > + > #endif /* _LINUX_IRQ_WORK_H */ > diff --git a/kernel/irq_work.c b/kernel/irq_work.c > index 64eddd5..b3c113a 100644 > --- a/kernel/irq_work.c > +++ b/kernel/irq_work.c > @@ -99,6 +99,17 @@ bool irq_work_queue(struct irq_work *work) > } > EXPORT_SYMBOL_GPL(irq_work_queue); > > +bool irq_work_needs_cpu(void) > +{ > + struct llist_head *this_list; > + > + this_list = &__get_cpu_var(irq_work_list); > + if (llist_empty(this_list)) > + return false; > + I wounder if this should just be: return !llist_empty(&this_cpu_read(irq_work_list)); -- Steve > + return true; > +} > + > /* > * Run the irq_work entries on this cpu. Requires to be ran from hardirq > * context with local IRQs disabled. > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 9e945aa..f249e8c 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -20,6 +20,7 @@ > #include > #include > #include > +#include > > #include > > @@ -289,7 +290,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, > } while (read_seqretry(&xtime_lock, seq)); > > if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || printk_needs_cpu(cpu) || > - arch_needs_cpu(cpu)) { > + arch_needs_cpu(cpu) || irq_work_needs_cpu()) { > next_jiffies = last_jiffies + 1; > delta_jiffies = 1; > } else { -- 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/