RE: [PATCH v6 2/4] perf: add arm64 smmuv3 pmu driver

[Shameerali Kolothum Thodi]

> -----Original Message-----
> From: linux-arm-kernel [mailto:linux-arm-kernel-bounces@xxxxxxxxxxxxxxxxxxx]
> On Behalf Of Robin Murphy
> Sent: 21 March 2019 15:04
> To: Shameerali Kolothum Thodi <shameerali.kolothum.thodi@xxxxxxxxxx>;
> lorenzo.pieralisi@xxxxxxx
> Cc: mark.rutland@xxxxxxx; vkilari@xxxxxxxxxxxxxx;
> neil.m.leeder@xxxxxxxxx; jean-philippe.brucker@xxxxxxx;
> pabba@xxxxxxxxxxxxxx; John Garry <john.garry@xxxxxxxxxx>;
> will.deacon@xxxxxxx; rruigrok@xxxxxxxxxxxxxx; Linuxarm
> <linuxarm@xxxxxxxxxx>; linux-kernel@xxxxxxxxxxxxxxx;
> linux-acpi@xxxxxxxxxxxxxxx; Guohanjun (Hanjun Guo)
> <guohanjun@xxxxxxxxxx>; andrew.murray@xxxxxxx;
> linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Subject: Re: [PATCH v6 2/4] perf: add arm64 smmuv3 pmu driver

[...]

> Ah, apologies for leading you wrong on this, but it has turned out to be
> bogus - perf_pmu_register() does things for which preemption should not
> be disabled, and it flares up particularly on PREEMPT_RT. For now, I
> think the best thing to do is to bring the put_cpu() call up here (or
> just use raw_smp_processor_id() instead) and accept that those
> vanishingly-unlikely-in-practice race conditions exist until someone can
> make the registration dance more robust in the perf core itself.
> 
> Beyond that, though, I'm trusting that everything I didn't comment on
> last time and doesn't appear at a glance to have changed is still good,
> so with the comments above addressed,
> 
> Reviewed-by: Robin Murphy <robin.murphy@xxxxxxx>
> 
> FYI, both Will and Mark are out for a while, so whilst I expect v7
> should be good to merge, don't expect any maintainer final say for at
> least a couple of weeks yet.
> 

Thanks Robin. I will address the comments and sent out v7 soon.

Cheers,
Shameer