Messages in this thread | | | Date | Wed, 29 Oct 2014 15:37:53 -0400 | From | Boris Ostrovsky <> | Subject | Re: [PATCH v3] xen/smp: Use die_complete completion when taking CPU down |
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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 <boris.ostrovsky@oracle.com> > Reviewed-by: David Vrabel <david.vrabel@citrix.com> > --- > > 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);
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