From: Peter Zijlstra <peterz@infradead.org>
To: Like Xu <like.xu@linux.intel.com>
Cc: Kan Liang <kan.liang@linux.intel.com>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@redhat.com>, Namhyung Kim <namhyung@kernel.org>,
Thomas Gleixner <tglx@linutronix.de>,
Borislav Petkov <bp@alien8.de>,
x86@kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH RESEND 2/2] perf/x86/lbr: Move cpuc->lbr_xsave allocation out of sleeping region
Date: Wed, 21 Apr 2021 11:21:09 +0200 [thread overview]
Message-ID: <YH/uhXEmQllOsIeK@hirez.programming.kicks-ass.net> (raw)
In-Reply-To: <13fd7ac4-46fd-3fa7-0e80-3f46cfc8edac@linux.intel.com>
On Wed, Apr 21, 2021 at 04:48:36PM +0800, Like Xu wrote:
> 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!
The nice one was here:
https://lkml.kernel.org/r/20210323214140.GE4746@worktop.programming.kicks-ass.net
> So do we have a better idea to alloc cpuc->lbr_xsave
> to avoid this kind of call trace ?
You thinking this is actually hard scares me. Frob something in
intel_pmu_hw_config() or thereabouts.
next prev parent reply other threads:[~2021-04-21 9:22 UTC|newest]
Thread overview: 8+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-04-21 2:18 [PATCH RESEND 1/2] perf/x86: Skip checking MSR for MSR 0x0 Like Xu
2021-04-21 2:18 ` [PATCH RESEND 2/2] perf/x86/lbr: Move cpuc->lbr_xsave allocation out of sleeping region Like Xu
2021-04-21 8:38 ` Peter Zijlstra
2021-04-21 8:48 ` Like Xu
2021-04-21 9:21 ` Peter Zijlstra [this message]
2021-04-21 15:30 ` [PATCH RESEND 1/2] perf/x86: Skip checking MSR for MSR 0x0 Sean Christopherson
2021-04-22 1:18 ` Like Xu
2021-04-22 1:38 ` Sean Christopherson
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