linux-kernel - Re: [PATCH V6 2/2] arm64: perf: add support for percpu pmu interrupt

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Message-ID: <20131203134113.GI1169@mudshark.cambridge.arm.com>
Date:	Tue, 3 Dec 2013 13:41:13 +0000
From:	Will Deacon <will.deacon@....com>
To:	Vinayak Kale <vkale@....com>
Cc:	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
	"linux-arm-kernel@...ts.infradead.org" 
	<linux-arm-kernel@...ts.infradead.org>,
	"tglx@...utronix.de" <tglx@...utronix.de>,
	"patches@....com" <patches@....com>,
	"jcm@...hat.com" <jcm@...hat.com>,
	"sboyd@...eaurora.org" <sboyd@...eaurora.org>,
	Marc Zyngier <Marc.Zyngier@....com>, Tuan Phan <tphan@....com>
Subject: Re: [PATCH V6 2/2] arm64: perf: add support for percpu pmu interrupt

On Tue, Dec 03, 2013 at 11:49:11AM +0000, Vinayak Kale wrote:
> On Tue, Dec 3, 2013 at 5:00 PM, Will Deacon <will.deacon@....com> wrote:
> > On Mon, Dec 02, 2013 at 09:34:03AM +0000, Vinayak Kale wrote:
> >> Add support for irq registration when pmu interrupt is percpu.
> >>
> >> Signed-off-by: Vinayak Kale <vkale@....com>
> >> Signed-off-by: Tuan Phan <tphan@....com>
> >> ---
> >>  arch/arm64/kernel/perf_event.c |  116 +++++++++++++++++++++++++++++-----------
> >>  1 file changed, 86 insertions(+), 30 deletions(-)
> >>
> >> diff --git a/arch/arm64/kernel/perf_event.c b/arch/arm64/kernel/perf_event.c
> >> index cea1594..d2d562f 100644
> >> --- a/arch/arm64/kernel/perf_event.c
> >> +++ b/arch/arm64/kernel/perf_event.c
> >> @@ -22,6 +22,7 @@
> >>
> >>  #include <linux/bitmap.h>
> >>  #include <linux/interrupt.h>
> >> +#include <linux/irq.h>
> >>  #include <linux/kernel.h>
> >>  #include <linux/export.h>
> >>  #include <linux/perf_event.h>
> >> @@ -363,26 +364,61 @@ validate_group(struct perf_event *event)
> >>  }
> >>
> >>  static void
> >> +armpmu_disable_percpu_irq(void *data)
> >> +{
> >> +     struct arm_pmu *armpmu = data;
> >> +     struct platform_device *pmu_device = armpmu->plat_device;
> >> +     int irq = platform_get_irq(pmu_device, 0);
> >> +
> >> +     cpumask_test_and_clear_cpu(smp_processor_id(), &armpmu->active_irqs);
> >> +     disable_percpu_irq(irq);
> >> +}
> >> +
> >> +static void
> >>  armpmu_release_hardware(struct arm_pmu *armpmu)
> >>  {
> >> -     int i, irq, irqs;
> >> +     int irq;
> >
> > Why did you not make this unsigned, like I suggested?
> 
> Suggestion was to make 'irqs' variable unsigned and modify the check
> for 'irqs' to if (!irqs).
> This patch incorporates that suggestion.
> 
> We have to keep 'irq' signed only. 'platform_get_irq()' can return error value.

Damn, yes, I see the issue there. Ok, I'll go back and take another look at
your patch...

Will
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