Re: [PATCH RESEND 2/2] perf/x86/lbr: Move cpuc->lbr_xsave allocation out of sleeping region

[Like Xu <like.xu@linux.intel.com>]

Hi Peter,

On 2021/4/21 16:38, Peter Zijlstra wrote:
> On Wed, Apr 21, 2021 at 10:18:25AM +0800, Like Xu wrote:
>> -int x86_reserve_hardware(void)
>> +int x86_reserve_hardware(struct perf_event *event)
>>   {
>>   	int err = 0;
>>   
>> @@ -398,8 +398,10 @@ int x86_reserve_hardware(void)
>>   		if (atomic_read(&pmc_refcount) == 0) {
>>   			if (!reserve_pmc_hardware())
>>   				err = -EBUSY;
>> -			else
>> +			else {
>>   				reserve_ds_buffers();
>> +				reserve_lbr_buffers(event);
>> +			}
>>   		}
>>   		if (!err)
>>   			atomic_inc(&pmc_refcount);
>> @@ -650,7 +652,7 @@ static int __x86_pmu_event_init(struct perf_event *event)
>>   	if (!x86_pmu_initialized())
>>   		return -ENODEV;
>>   
>> -	err = x86_reserve_hardware();
>> +	err = x86_reserve_hardware(event);
>>   	if (err)
>>   		return err;
>>   
> 
> This is still complete garbage..

Hhh,thanks for your comment!

So do we have a better idea to alloc cpuc->lbr_xsave
to avoid this kind of call trace ?

>