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Subject: Re: [PATCH 21/21] perf/x86/intel/lbr: Support XSAVES for arch LBR
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To:     Cyrill Gorcunov <gorcunov@gmail.com>
Cc:     peterz@infradead.org, mingo@redhat.com, acme@kernel.org,
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References: <1592575449-64278-1-git-send-email-kan.liang@linux.intel.com>
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 <20200622184937.GV134822@grain>
From:   "Liang, Kan" <kan.liang@linux.intel.com>
Message-ID: <3492fcad-344d-174e-7e38-46f2e543b065@linux.intel.com>
Date:   Mon, 22 Jun 2020 15:11:07 -0400
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On 6/22/2020 2:49 PM, Cyrill Gorcunov wrote:
> On Fri, Jun 19, 2020 at 07:04:09AM -0700, kan.liang@linux.intel.com wrote:
> ...
>> +static void intel_pmu_arch_lbr_read_xsave(struct cpu_hw_events *cpuc)
>> +{
>> +	struct x86_perf_task_context_arch_lbr_xsave *xsave = cpuc->lbr_xsave;
>> +	struct arch_lbr_entry *lbr;
>> +	int i;
>> +
>> +	if (!xsave)
>> +		goto rollback;
> 
> Why not make it simplier?
> 
> 	if (!xsave) {
> 		intel_pmu_arch_lbr_read(cpuc);
> 		return;
> 	}
> 
> The goto and "return" statement before the "rollback" label
> looks pretty ugly. I'm sorry I didn't follow the series
> in details so if you plan to add more handlers at "rollback"
> then sure.
> 

There were several handlers when I first implemented the function, but 
they are removed now. I don't think I will add more handlers in the next 
version.
I will remove the "rollback" label.

Thanks for pointing it out.

Kan