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Message-ID: <84626c83-8806-d807-a7bf-b497f70e56fd@ghiti.fr>
Date:   Thu, 15 Jun 2023 09:10:24 +0200
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Subject: Re: [PATCH v2 01/10] perf: Fix wrong comment about default event_idx
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To:     Andrew Jones <ajones@ventanamicro.com>,
        Alexandre Ghiti <alexghiti@rivosinc.com>
Cc:     Jonathan Corbet <corbet@lwn.net>,
        Peter Zijlstra <peterz@infradead.org>,
        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@kernel.org>,
        Namhyung Kim <namhyung@kernel.org>,
        Ian Rogers <irogers@google.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Albert Ou <aou@eecs.berkeley.edu>,
        Atish Patra <atishp@atishpatra.org>,
        Anup Patel <anup@brainfault.org>,
        Will Deacon <will@kernel.org>, Rob Herring <robh@kernel.org>,
        linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org,
        linux-perf-users@vger.kernel.org, linux-riscv@lists.infradead.org,
        linux-arm-kernel@lists.infradead.org
References: <20230512085321.13259-1-alexghiti@rivosinc.com>
 <20230512085321.13259-2-alexghiti@rivosinc.com>
 <20230531-5678beb107af4b9805cbb611@orel>
From:   Alexandre Ghiti <alex@ghiti.fr>
In-Reply-To: <20230531-5678beb107af4b9805cbb611@orel>
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On 31/05/2023 15:54, Andrew Jones wrote:
> On Fri, May 12, 2023 at 10:53:12AM +0200, Alexandre Ghiti wrote:
>> event_idx default implementation returns 0, not idx + 1.
> The comment was correct until commit c719f56092ad ("perf: Fix and clean
> up initialization of pmu::event_idx"). I'm not sure that warrants a fixes
> tag, but maybe a reference in the commit message.


You're right, I'll add a reference, I don't think it deserves a 
backport, that's just a comment.


>> Signed-off-by: Alexandre Ghiti <alexghiti@rivosinc.com>
>> ---
>>   include/linux/perf_event.h | 3 ++-
>>   1 file changed, 2 insertions(+), 1 deletion(-)
>>
>> diff --git a/include/linux/perf_event.h b/include/linux/perf_event.h
>> index d5628a7b5eaa..56fe43b20966 100644
>> --- a/include/linux/perf_event.h
>> +++ b/include/linux/perf_event.h
>> @@ -442,7 +442,8 @@ struct pmu {
>>   
>>   	/*
>>   	 * Will return the value for perf_event_mmap_page::index for this event,
>> -	 * if no implementation is provided it will default to: event->hw.idx + 1.
>> +	 * if no implementation is provided it will default to 0 (see
>> +	 * perf_event_idx_default).
>>   	 */
>>   	int (*event_idx)		(struct perf_event *event); /*optional */
>>   
>> -- 
>> 2.37.2
>>
> Otherwise,
>
> Reviewed-by: Andrew Jones <ajones@ventanamicro.com>


Thanks!