Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S968018Ab2ERN3I (ORCPT ); Fri, 18 May 2012 09:29:08 -0400 Received: from e28smtp04.in.ibm.com ([122.248.162.4]:40447 "EHLO e28smtp04.in.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S967241Ab2ERN3G (ORCPT ); Fri, 18 May 2012 09:29:06 -0400 Message-ID: <4FB64E9A.3060100@linux.vnet.ibm.com> Date: Fri, 18 May 2012 18:58:58 +0530 From: Deepthi Dharwar User-Agent: Mozilla/5.0 (X11; Linux i686; rv:11.0) Gecko/20120329 Thunderbird/11.0.1 MIME-Version: 1.0 To: Benjamin Herrenschmidt , Li Zhong , "Paul E. McKenney" , Paul Mackerras , "linux-kernel@vger.kernel.org" , PowerPC email list Subject: [PATCH] cpuidle: (POWER) Replace pseries_notify_cpuidle_add call with a elegant notifier to fix lockdep problem in start_secondary Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit x-cbid: 12051813-5564-0000-0000-000002C5E9FC Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3524 Lines: 111 The following patch is to remove the pseries_notify_add_cpu() call and replace it by a hot plug notifier. This would prevent cpuidle resources being released and allocated each time cpu comes online on pseries. The earlier design was causing a lockdep problem in start_secondary as reported on this thread -https://lkml.org/lkml/2012/5/17/2 This applies on 3.4-rc7 Signed-off-by: Deepthi Dharwar --- arch/powerpc/include/asm/processor.h | 2 -- arch/powerpc/platforms/pseries/processor_idle.c | 25 +++++++++++++++++------ arch/powerpc/platforms/pseries/smp.c | 1 - 3 files changed, 19 insertions(+), 9 deletions(-) diff --git a/arch/powerpc/include/asm/processor.h b/arch/powerpc/include/asm/processor.h index 8e2d037..c6bc22b 100644 --- a/arch/powerpc/include/asm/processor.h +++ b/arch/powerpc/include/asm/processor.h @@ -390,10 +390,8 @@ void cpu_idle_wait(void); #ifdef CONFIG_PSERIES_IDLE extern void update_smt_snooze_delay(int snooze); -extern int pseries_notify_cpuidle_add_cpu(int cpu); #else static inline void update_smt_snooze_delay(int snooze) {} -static inline int pseries_notify_cpuidle_add_cpu(int cpu) { return 0; } #endif extern void flush_instruction_cache(void); diff --git a/arch/powerpc/platforms/pseries/processor_idle.c b/arch/powerpc/platforms/pseries/processor_idle.c index 41a34bc..d1a7dc0 100644 --- a/arch/powerpc/platforms/pseries/processor_idle.c +++ b/arch/powerpc/platforms/pseries/processor_idle.c @@ -11,6 +11,7 @@ #include #include #include +#include #include #include @@ -186,17 +187,28 @@ static struct cpuidle_state shared_states[MAX_IDLE_STATE_COUNT] = { .enter = &shared_cede_loop }, }; -int pseries_notify_cpuidle_add_cpu(int cpu) +static int pseries_cpuidle_add_cpu_notifier(struct notifier_block *n, + unsigned long action, void *hcpu) { + int hotcpu = (unsigned long)hcpu; struct cpuidle_device *dev = - per_cpu_ptr(pseries_cpuidle_devices, cpu); - if (dev && cpuidle_get_driver()) { - cpuidle_disable_device(dev); - cpuidle_enable_device(dev); + per_cpu_ptr(pseries_cpuidle_devices, hotcpu); + + switch (action & 0xf) { + case CPU_ONLINE: + if (dev && cpuidle_get_driver()) { + cpuidle_disable_device(dev); + cpuidle_enable_device(dev); + } + break; } - return 0; + return NOTIFY_OK; } +static struct notifier_block setup_hotplug_notifier = { + .notifier_call = pseries_cpuidle_add_cpu_notifier, +}; + /* * pseries_cpuidle_driver_init() */ @@ -321,6 +333,7 @@ static int __init pseries_processor_idle_init(void) return retval; } + register_cpu_notifier(&setup_hotplug_notifier); printk(KERN_DEBUG "pseries_idle_driver registered\n"); return 0; diff --git a/arch/powerpc/platforms/pseries/smp.c b/arch/powerpc/platforms/pseries/smp.c index e16bb8d..71706bc 100644 --- a/arch/powerpc/platforms/pseries/smp.c +++ b/arch/powerpc/platforms/pseries/smp.c @@ -147,7 +147,6 @@ static void __devinit smp_xics_setup_cpu(int cpu) set_cpu_current_state(cpu, CPU_STATE_ONLINE); set_default_offline_state(cpu); #endif - pseries_notify_cpuidle_add_cpu(cpu); } static int __devinit smp_pSeries_kick_cpu(int nr) -- 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/