Re: [Xen-devel] [RFC PATCH V3 1/3] Xen: Increase hap/shadow page pool size to support more vcpus support

[Lan Tianyu <tianyu.lan@xxxxxxxxx>]

Hi Wei:

On 2017年09月18日 21:06, Wei Liu wrote:
> On Wed, Sep 13, 2017 at 12:52:47AM -0400, Lan Tianyu wrote:
>> This patch is to increase page pool size when max vcpu number is larger
>> than 128.
>>
>> Signed-off-by: Lan Tianyu <tianyu.lan@xxxxxxxxx>
>> ---
>>  xen/arch/arm/domain.c    |  5 +++++
>>  xen/arch/x86/domain.c    | 25 +++++++++++++++++++++++++
>>  xen/common/domctl.c      |  3 +++
>>  xen/include/xen/domain.h |  2 ++
>>  4 files changed, 35 insertions(+)
>>
>> diff --git a/xen/arch/arm/domain.c b/xen/arch/arm/domain.c
>> index 6512f01..94cf70b 100644
>> --- a/xen/arch/arm/domain.c
>> +++ b/xen/arch/arm/domain.c
>> @@ -824,6 +824,11 @@ int arch_vcpu_reset(struct vcpu *v)
>>      return 0;
>>  }
>>  
>> +int arch_domain_set_max_vcpus(struct domain *d)
>> +{
>> +    return 0;
>> +}
>> +
>>  static int relinquish_memory(struct domain *d, struct page_list_head *list)
>>  {
>>      struct page_info *page, *tmp;
>> diff --git a/xen/arch/x86/domain.c b/xen/arch/x86/domain.c
>> index dbddc53..0e230f9 100644
>> --- a/xen/arch/x86/domain.c
>> +++ b/xen/arch/x86/domain.c
>> @@ -1161,6 +1161,31 @@ int arch_vcpu_reset(struct vcpu *v)
>>      return 0;
>>  }
>>  
>> +int arch_domain_set_max_vcpus(struct domain *d)
> 
> The name doesn't match what the function does.
> 

I originally hoped to introduce a hook for each arch when set max vcpus.
Each arch function can do customized thing and so named
"arch_domain_set_max_vcpus".

How about "arch_domain_setup_vcpus_resource"?


>> +{
>> +    int ret;
>> +
>> +    /* Increase page pool in order to support more vcpus. */
>> +    if ( d->max_vcpus > 128 )
>> +    {
>> +        unsigned long nr_pages;
>> +
>> +        if (hap_enabled(d))
> 
> Coding style.

Will update. Thanks.

> 
>> +            nr_pages = 1024;
>> +        else
>> +            nr_pages = 4096;
>> +
>> +        ret = paging_set_allocation(d, nr_pages, NULL);
> 
> Does this work on PV guests?


Sorry. This code should not run for PV guest. Will add a domain type
check here.

> 
>> +        if ( ret != 0 )
>> +        {
>> +            paging_set_allocation(d, 0, NULL);
>> +            return ret;
>> +        }
>> +    }
>> +
>> +    return 0;
>> +}
>> +
>>  long
>>  arch_do_vcpu_op(
>>      int cmd, struct vcpu *v, XEN_GUEST_HANDLE_PARAM(void) arg)
>> diff --git a/xen/common/domctl.c b/xen/common/domctl.c
>> index 42658e5..64357a3 100644
>> --- a/xen/common/domctl.c
>> +++ b/xen/common/domctl.c
>> @@ -631,6 +631,9 @@ long do_domctl(XEN_GUEST_HANDLE_PARAM(xen_domctl_t) 
>> u_domctl)
>>              d->max_vcpus = max;
>>          }
>>  
>> +        if ( arch_domain_set_max_vcpus(d) < 0)
> 
> != 0 please.
> 

Sure.

>> +            goto maxvcpu_out;
>> +
>>          for ( i = 0; i < max; i++ )
>>          {
>>              if ( d->vcpu[i] != NULL )
>> diff --git a/xen/include/xen/domain.h b/xen/include/xen/domain.h
>> index 347f264..e1ece3a 100644
>> --- a/xen/include/xen/domain.h
>> +++ b/xen/include/xen/domain.h
>> @@ -81,6 +81,8 @@ void arch_dump_domain_info(struct domain *d);
>>  
>>  int arch_vcpu_reset(struct vcpu *);
>>  
>> +int arch_domain_set_max_vcpus(struct domain *d);
>> +
>>  extern spinlock_t vcpu_alloc_lock;
>>  bool_t domctl_lock_acquire(void);
>>  void domctl_lock_release(void);
>> -- 
>> 1.8.3.1
>>


-- 
Best regards
Tianyu Lan

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