Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756847AbaJ2TgP (ORCPT ); Wed, 29 Oct 2014 15:36:15 -0400 Received: from userp1040.oracle.com ([156.151.31.81]:43553 "EHLO userp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751165AbaJ2TgM (ORCPT ); Wed, 29 Oct 2014 15:36:12 -0400 Message-ID: <54514211.9@oracle.com> Date: Wed, 29 Oct 2014 15:37:53 -0400 From: Boris Ostrovsky User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:24.0) Gecko/20100101 Thunderbird/24.2.0 MIME-Version: 1.0 To: hpa@zytor.com, mingo@redhat.com, tglx@linutronix.de CC: david.vrabel@citrix.com, konrad.wilk@oracle.com, tianyu.lan@intel.com, linux-kernel@vger.kernel.org, xen-devel@lists.xenproject.org, boris.ostrovsky@oracle.com Subject: Re: [PATCH v3] xen/smp: Use die_complete completion when taking CPU down References: <1413997748-29808-1-git-send-email-boris.ostrovsky@oracle.com> In-Reply-To: <1413997748-29808-1-git-send-email-boris.ostrovsky@oracle.com> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-Source-IP: ucsinet22.oracle.com [156.151.31.94] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 10/22/2014 01:09 PM, Boris Ostrovsky wrote: > Commit 2ed53c0d6cc9 ("x86/smpboot: Speed up suspend/resume by avoiding > 100ms sleep for CPU offline during S3") introduced completions to CPU > offlining process. These completions are not initialized on Xen kernels > causing a panic in play_dead_common(). > > Move handling of die_complete into common routines to make them > available to Xen guests. > > (While at it, move die_complete definition under #ifdef CONFIG_HOTPLUG_CPU) > > Signed-off-by: Boris Ostrovsky > Reviewed-by: David Vrabel > --- > > v3: Don't #ifdef function prototypes in smp.h > v2: Keep die_complete private to smpboot.c > > > arch/x86/include/asm/smp.h | 1 + > arch/x86/kernel/smpboot.c | 13 +++++++++++-- > arch/x86/xen/smp.c | 3 +++ > 3 files changed, 15 insertions(+), 2 deletions(-) Does anything else need to be done in this patch? We have CPU hotplug broken currently in Xen and it would be nice to have it fixed in rc3. -boris > > diff --git a/arch/x86/include/asm/smp.h b/arch/x86/include/asm/smp.h > index 8cd27e0..8cd1cc3 100644 > --- a/arch/x86/include/asm/smp.h > +++ b/arch/x86/include/asm/smp.h > @@ -150,6 +150,7 @@ static inline void arch_send_call_function_ipi_mask(const struct cpumask *mask) > } > > void cpu_disable_common(void); > +void cpu_die_common(unsigned int cpu); > void native_smp_prepare_boot_cpu(void); > void native_smp_prepare_cpus(unsigned int max_cpus); > void native_smp_cpus_done(unsigned int max_cpus); > diff --git a/arch/x86/kernel/smpboot.c b/arch/x86/kernel/smpboot.c > index 2d5200e..6fe0fc1 100644 > --- a/arch/x86/kernel/smpboot.c > +++ b/arch/x86/kernel/smpboot.c > @@ -102,7 +102,9 @@ DEFINE_PER_CPU_READ_MOSTLY(cpumask_var_t, cpu_llc_shared_map); > DEFINE_PER_CPU_SHARED_ALIGNED(struct cpuinfo_x86, cpu_info); > EXPORT_PER_CPU_SYMBOL(cpu_info); > > +#ifdef CONFIG_HOTPLUG_CPU > static DEFINE_PER_CPU(struct completion, die_complete); > +#endif > > atomic_t init_deasserted; > > @@ -1309,6 +1311,8 @@ void cpu_disable_common(void) > { > int cpu = smp_processor_id(); > > + init_completion(&per_cpu(die_complete, smp_processor_id())); > + > remove_siblinginfo(cpu); > > /* It's now safe to remove this processor from the online map */ > @@ -1327,16 +1331,21 @@ int native_cpu_disable(void) > return ret; > > clear_local_APIC(); > - init_completion(&per_cpu(die_complete, smp_processor_id())); > cpu_disable_common(); > > return 0; > } > > +void cpu_die_common(unsigned int cpu) > +{ > + wait_for_completion_timeout(&per_cpu(die_complete, cpu), HZ); > +} > + > void native_cpu_die(unsigned int cpu) > { > /* We don't do anything here: idle task is faking death itself. */ > - wait_for_completion_timeout(&per_cpu(die_complete, cpu), HZ); > + > + cpu_die_common(cpu); > > /* They ack this in play_dead() by setting CPU_DEAD */ > if (per_cpu(cpu_state, cpu) == CPU_DEAD) { > diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c > index 8650cdb..4c071ae 100644 > --- a/arch/x86/xen/smp.c > +++ b/arch/x86/xen/smp.c > @@ -510,6 +510,9 @@ static void xen_cpu_die(unsigned int cpu) > current->state = TASK_UNINTERRUPTIBLE; > schedule_timeout(HZ/10); > } > + > + cpu_die_common(cpu); > + > xen_smp_intr_free(cpu); > xen_uninit_lock_cpu(cpu); > xen_teardown_timer(cpu); -- 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/