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

[Like Xu]

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 ?

>