From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754207Ab3AaMLj (ORCPT ); Thu, 31 Jan 2013 07:11:39 -0500 Received: from www.linutronix.de ([62.245.132.108]:55909 "EHLO Galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751728Ab3AaMLX (ORCPT ); Thu, 31 Jan 2013 07:11:23 -0500 Message-Id: <20130131120741.553993267@linutronix.de> User-Agent: quilt/0.48-1 Date: Thu, 31 Jan 2013 12:11:12 -0000 From: Thomas Gleixner To: LKML Cc: Ingo Molnar , Peter Zijlstra , Rusty Russell , Paul McKenney , "Srivatsa S. Bhat" , Arjan van de Veen , Paul Turner , Richard Weinberger , Magnus Damm Subject: [patch 01/40] smpboot: Allow selfparking per cpu threads References: <20130131120348.372374706@linutronix.de> Content-Disposition: inline; filename=smpboot-allow-selfstopping-threads.patch X-Linutronix-Spam-Score: -1.0 X-Linutronix-Spam-Level: - X-Linutronix-Spam-Status: No , -1.0 points, 5.0 required, ALL_TRUSTED=-1,SHORTCIRCUIT=-0.0001 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The stop machine threads are still killed when a cpu goes offline. The reason is that the thread is used to bring the cpu down, so it can't be parked along with the other per cpu threads. Allow a per cpu thread to be excluded from automatic parking, so it can park itself once it's done Add a create callback function as well. Signed-off-by: Thomas Gleixner --- include/linux/smpboot.h | 5 +++++ kernel/smpboot.c | 5 +++-- 2 files changed, 8 insertions(+), 2 deletions(-) Index: linux-2.6/include/linux/smpboot.h =================================================================== --- linux-2.6.orig/include/linux/smpboot.h +++ linux-2.6/include/linux/smpboot.h @@ -14,6 +14,8 @@ struct smpboot_thread_data; * @thread_should_run: Check whether the thread should run or not. Called with * preemption disabled. * @thread_fn: The associated thread function + * @create: Optional setup function, called when the thread gets + * created (Not called from the thread context) * @setup: Optional setup function, called when the thread gets * operational the first time * @cleanup: Optional cleanup function, called when the thread @@ -22,6 +24,7 @@ struct smpboot_thread_data; * parked (cpu offline) * @unpark: Optional unpark function, called when the thread is * unparked (cpu online) + * @selfparking: Thread is not parked by the park function. * @thread_comm: The base name of the thread */ struct smp_hotplug_thread { @@ -29,10 +32,12 @@ struct smp_hotplug_thread { struct list_head list; int (*thread_should_run)(unsigned int cpu); void (*thread_fn)(unsigned int cpu); + void (*create)(unsigned int cpu); void (*setup)(unsigned int cpu); void (*cleanup)(unsigned int cpu, bool online); void (*park)(unsigned int cpu); void (*unpark)(unsigned int cpu); + bool selfparking; const char *thread_comm; }; Index: linux-2.6/kernel/smpboot.c =================================================================== --- linux-2.6.orig/kernel/smpboot.c +++ linux-2.6/kernel/smpboot.c @@ -183,9 +183,10 @@ __smpboot_create_thread(struct smp_hotpl kfree(td); return PTR_ERR(tsk); } - get_task_struct(tsk); *per_cpu_ptr(ht->store, cpu) = tsk; + if (ht->create) + ht->create(cpu); return 0; } @@ -225,7 +226,7 @@ static void smpboot_park_thread(struct s { struct task_struct *tsk = *per_cpu_ptr(ht->store, cpu); - if (tsk) + if (tsk && !ht->selfparking) kthread_park(tsk); }