Re: [Xen-devel] [PATCH] When flush tlb , we need consider the cpu_online_map

[Keir Fraser <keir.fraser@xxxxxxxxxxxxx>]

Sounds good. Can you please re-spin the patch, Yunhong? I will drop your
original patch for now.

 -- Keir

On 29/03/2010 13:55, "Jan Beulich" <JBeulich@xxxxxxxxxx> wrote:

>>>> "Jiang, Yunhong" <yunhong.jiang@xxxxxxxxx> 29.03.10 14:00 >>>
>> When flush tlb mask, we need consider the cpu_online_map. The same happens to
>> ept flush also.
> 
> While the idea is certainly correct, doing this more efficiently seems
> quite desirable to me, especially when NR_CPUS is large:
> 
>> --- a/xen/arch/x86/hvm/vmx/vmx.c Sat Mar 27 16:01:35 2010 +0000
>> +++ b/xen/arch/x86/hvm/vmx/vmx.c Mon Mar 29 17:49:51 2010 +0800
>> @@ -1235,6 +1235,9 @@ void ept_sync_domain(struct domain *d)
>>      * unnecessary extra flushes, to avoid allocating a cpumask_t on the
>> stack.
>>      */
>>     d->arch.hvm_domain.vmx.ept_synced = d->domain_dirty_cpumask;
>> +    cpus_and(d->arch.hvm_domain.vmx.ept_synced,
>> +             d->arch.hvm_domain.vmx.ept_synced,
>> +             cpu_online_map);
> 
> The added code can be combined with the pre-existing line:
> 
>     cpus_and(d->arch.hvm_domain.vmx.ept_synced,
>              d->domain_dirty_cpumask, cpu_online_map);
> 
>>     on_selected_cpus(&d->arch.hvm_domain.vmx.ept_synced,
>>                      __ept_sync_domain, d, 1);
>> }
>> --- a/xen/arch/x86/smp.c Sat Mar 27 16:01:35 2010 +0000
>> +++ b/xen/arch/x86/smp.c Mon Mar 29 17:47:25 2010 +0800
>> @@ -229,6 +229,7 @@ void flush_area_mask(const cpumask_t *ma
>>     {
>>         spin_lock(&flush_lock);
>>         cpus_andnot(flush_cpumask, *mask, *cpumask_of(smp_processor_id()));
>> +        cpus_and(flush_cpumask, cpu_online_map, flush_cpumask);
> 
> Here, first doing the full-mask operation and then clearing the one
> extra bit is less overhead:
> 
>         cpus_and(flush_cpumask, *mask, cpu_online_map);
>         cpu_clear(smp_processor_id(), flush_cpumask);
> 
>>         flush_va      = va;
>>         flush_flags   = flags;
>>         send_IPI_mask(&flush_cpumask, INVALIDATE_TLB_VECTOR);
> 
> Jan
> 
> 
> 



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