Re: [Xen-devel] [PATCH] x86/S3: Restore broken vcpu affinity on resume

[Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>]

On 26.03.2013 18:20, Ben Guthro wrote:
> When in SYS_STATE_suspend, and going through the cpu_disable_scheduler
> path, save a copy of the current cpu affinity, and mark a flag to
> restore it later.
>
> Later, in the resume process, when enabling nonboot cpus restore these
> affinities.
>
> This is the second submission of this patch.
> Primary differences from the first patch is to fix formatting problems.
> However, when doing so, I tested with another patch in the
> cpu_disable_scheduler() path that is also appropriate here.
>
> Signed-off-by: Ben Guthro<benjamin.guthro@xxxxxxxxxx>
Acked-by: Juergen Gross <juergen.gross@xxxxxxxxxxxxxx>

> ---
>   xen/common/cpu.c           |    3 +++
>   xen/common/cpupool.c       |    5 +----
>   xen/common/domain.c        |    2 ++
>   xen/common/schedule.c      |   49 +++++++++++++++++++++++++++++++++++++++++++-
>   xen/include/xen/sched-if.h |    5 +++++
>   xen/include/xen/sched.h    |    6 ++++++
>   6 files changed, 65 insertions(+), 5 deletions(-)
>
> diff --git a/xen/common/cpu.c b/xen/common/cpu.c
> index 630881e..3c77406 100644
> --- a/xen/common/cpu.c
> +++ b/xen/common/cpu.c
> @@ -215,4 +215,7 @@ void enable_nonboot_cpus(void)
>       }
>
>       cpumask_clear(&frozen_cpus);
> +
> +    if (system_state == SYS_STATE_resume)
> +        restore_vcpu_affinity();
>   }
> diff --git a/xen/common/cpupool.c b/xen/common/cpupool.c
> index 10b10f8..7a04f5e 100644
> --- a/xen/common/cpupool.c
> +++ b/xen/common/cpupool.c
> @@ -19,13 +19,10 @@
>   #include<xen/sched-if.h>
>   #include<xen/cpu.h>
>
> -#define for_each_cpupool(ptr)    \
> -    for ((ptr) =&cpupool_list; *(ptr) != NULL; (ptr) =&((*(ptr))->next))
> -
>   struct cpupool *cpupool0;                /* Initial cpupool with Dom0 */
>   cpumask_t cpupool_free_cpus;             /* cpus not in any cpupool */
>
> -static struct cpupool *cpupool_list;     /* linked list, sorted by poolid */
> +struct cpupool *cpupool_list;     /* linked list, sorted by poolid */
>
>   static int cpupool_moving_cpu = -1;
>   static struct cpupool *cpupool_cpu_moving = NULL;
> diff --git a/xen/common/domain.c b/xen/common/domain.c
> index 64ee29d..590548e 100644
> --- a/xen/common/domain.c
> +++ b/xen/common/domain.c
> @@ -126,6 +126,7 @@ struct vcpu *alloc_vcpu(
>
>       if ( !zalloc_cpumask_var(&v->cpu_affinity) ||
>            !zalloc_cpumask_var(&v->cpu_affinity_tmp) ||
> +         !zalloc_cpumask_var(&v->cpu_affinity_saved) ||
>            !zalloc_cpumask_var(&v->vcpu_dirty_cpumask) )
>           goto fail_free;
>
> @@ -155,6 +156,7 @@ struct vcpu *alloc_vcpu(
>    fail_free:
>           free_cpumask_var(v->cpu_affinity);
>           free_cpumask_var(v->cpu_affinity_tmp);
> +        free_cpumask_var(v->cpu_affinity_saved);
>           free_cpumask_var(v->vcpu_dirty_cpumask);
>           free_vcpu_struct(v);
>           return NULL;
> diff --git a/xen/common/schedule.c b/xen/common/schedule.c
> index 83fae4c..3e4d4ad 100644
> --- a/xen/common/schedule.c
> +++ b/xen/common/schedule.c
> @@ -541,6 +541,46 @@ void vcpu_force_reschedule(struct vcpu *v)
>       }
>   }
>
> +void restore_vcpu_affinity()
> +{
> +    struct domain *d;
> +    struct vcpu *v;
> +    struct cpupool **c;
> +
> +    for_each_cpupool(c)
> +    {
> +        for_each_domain_in_cpupool ( d, *c )
> +        {
> +            for_each_vcpu ( d, v )
> +            {
> +                vcpu_schedule_lock_irq(v);
> +
> +                if (v->affinity_broken)
> +                {
> +                    printk("Restoring vcpu affinity for domain %d vcpu %d\n",
> +                            v->domain->domain_id, v->vcpu_id);
> +                    cpumask_copy(v->cpu_affinity, v->cpu_affinity_saved);
> +                    v->affinity_broken = 0;
> +                }
> +
> +                if ( v->processor == smp_processor_id() )
> +                {
> +                    set_bit(_VPF_migrating,&v->pause_flags);
> +                    vcpu_schedule_unlock_irq(v);
> +                    vcpu_sleep_nosync(v);
> +                    vcpu_migrate(v);
> +                }
> +                else
> +                {
> +                    vcpu_schedule_unlock_irq(v);
> +                }
> +            }
> +
> +            domain_update_node_affinity(d);
> +        }
> +    }
> +}
> +
>   /*
>    * This function is used by cpu_hotplug code from stop_machine context
>    * and from cpupools to switch schedulers on a cpu.
> @@ -554,7 +594,7 @@ int cpu_disable_scheduler(unsigned int cpu)
>       int    ret = 0;
>
>       c = per_cpu(cpupool, cpu);
> -    if ( (c == NULL) || (system_state == SYS_STATE_suspend) )
> +    if ( c == NULL )
>           return ret;
>
>       for_each_domain_in_cpupool ( d, c )
> @@ -569,6 +609,13 @@ int cpu_disable_scheduler(unsigned int cpu)
>               {
>                   printk("Breaking vcpu affinity for domain %d vcpu %d\n",
>                           v->domain->domain_id, v->vcpu_id);
> +
> +                if (system_state == SYS_STATE_suspend)
> +               {
> +                    cpumask_copy(v->cpu_affinity_saved, v->cpu_affinity);
> +                    v->affinity_broken = 1;
> +                }
> +
>                   cpumask_setall(v->cpu_affinity);
>               }
>
> diff --git a/xen/include/xen/sched-if.h b/xen/include/xen/sched-if.h
> index 9ace22c..547e71e 100644
> --- a/xen/include/xen/sched-if.h
> +++ b/xen/include/xen/sched-if.h
> @@ -13,6 +13,9 @@
>   /* A global pointer to the initial cpupool (POOL0). */
>   extern struct cpupool *cpupool0;
>
> +/* linked list of cpu pools */
> +extern struct cpupool *cpupool_list;
> +
>   /* cpus currently in no cpupool */
>   extern cpumask_t cpupool_free_cpus;
>
> @@ -211,5 +214,7 @@ struct cpupool
>       (((_pool) == NULL) ?&cpupool_free_cpus : (_pool)->cpu_valid)
>   #define cpupool_online_cpumask(_pool) \
>       (((_pool) == NULL) ?&cpu_online_map : (_pool)->cpu_valid)
> +#define for_each_cpupool(ptr)    \
> +    for ((ptr) =&cpupool_list; *(ptr) != NULL; (ptr) =&((*(ptr))->next))
>
>   #endif /* __XEN_SCHED_IF_H__ */
> diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
> index cabaf27..d24fc6b 100644
> --- a/xen/include/xen/sched.h
> +++ b/xen/include/xen/sched.h
> @@ -153,6 +153,9 @@ struct vcpu
>       bool_t           defer_shutdown;
>       /* VCPU is paused following shutdown request (d->is_shutting_down)? */
>       bool_t           paused_for_shutdown;
> +    /* VCPU need affinity restored */
> +    bool_t           affinity_broken;
> +
>
>       /*
>        *>  0: a single port is being polled;
> @@ -175,6 +178,8 @@ struct vcpu
>       cpumask_var_t    cpu_affinity;
>       /* Used to change affinity temporarily. */
>       cpumask_var_t    cpu_affinity_tmp;
> +    /* Used to restore affinity across S3. */
> +    cpumask_var_t    cpu_affinity_saved;
>
>       /* Bitmask of CPUs which are holding onto this VCPU's state. */
>       cpumask_var_t    vcpu_dirty_cpumask;
> @@ -697,6 +702,7 @@ int schedule_cpu_switch(unsigned int cpu, struct cpupool 
> *c);
>   void vcpu_force_reschedule(struct vcpu *v);
>   int cpu_disable_scheduler(unsigned int cpu);
>   int vcpu_set_affinity(struct vcpu *v, const cpumask_t *affinity);
> +void restore_vcpu_affinity(void);
>
>   void vcpu_runstate_get(struct vcpu *v, struct vcpu_runstate_info *runstate);
>   uint64_t get_cpu_idle_time(unsigned int cpu);

--
Juergen Gross                 Principal Developer Operating Systems
PBG PDG ES&S SWE OS6                   Telephone: +49 (0) 89 3222 2967
Fujitsu Technology Solutions              e-mail: juergen.gross@xxxxxxxxxxxxxx
Domagkstr. 28                           Internet: ts.fujitsu.com
D-80807 Muenchen                 Company details: ts.fujitsu.com/imprint.html

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