linux-kernel - Re: [PATCH v7 2/4] libperf: Add evsel mmap support

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Date:   Wed, 14 Apr 2021 07:22:19 -0300
From:   Arnaldo Carvalho de Melo <acme@...nel.org>
To:     Rob Herring <robh@...nel.org>
Cc:     Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>, Jiri Olsa <jolsa@...hat.com>,
        "linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>,
        Will Deacon <will@...nel.org>,
        Catalin Marinas <catalin.marinas@....com>,
        Mark Rutland <mark.rutland@....com>,
        Namhyung Kim <namhyung@...nel.org>,
        Itaru Kitayama <itaru.kitayama@...il.com>
Subject: Re: [PATCH v7 2/4] libperf: Add evsel mmap support

Em Tue, Apr 13, 2021 at 02:07:57PM -0500, Rob Herring escreveu:
> On Tue, Apr 13, 2021 at 1:39 PM Arnaldo Carvalho de Melo <acme@...nel.org> wrote:
> > > --- a/tools/lib/perf/evsel.c
> > > +int perf_evsel__mmap(struct perf_evsel *evsel, int pages)
> > > +{
> > > +     int ret, cpu, thread;
> > Where is the counterpart?
> 
> I was assuming implicitly unmapped when closing the fd(s), but looks
> like it's when exiting the process only.
> 
> I.e. perf_evsel__munmap(), and it should be
> > called if perf_evsel__mmap() fails, right?
> 
> If perf_evsel__mmap() fails, the caller shouldn't have to do anything
> WRT mmap, right? But if the perf_mmap__mmap() call fails, we do need
> some internal clean-up. I'll fix both.

You're right, thanks!

- Arnaldo