linux-kernel - Re: [PATCH v1 2/4] perf evsel: Missed close when probing hybrid core PMUs

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Message-ID: <aFBFOBUhHnF87R9q@x1>
Date: Mon, 16 Jun 2025 13:24:24 -0300
From: Arnaldo Carvalho de Melo <acme@...nel.org>
To: Ian Rogers <irogers@...gle.com>
Cc: Peter Zijlstra <peterz@...radead.org>, Ingo Molnar <mingo@...hat.com>,
	Namhyung Kim <namhyung@...nel.org>,
	Mark Rutland <mark.rutland@....com>,
	Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
	Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Kan Liang <kan.liang@...ux.intel.com>,
	Michael Petlan <mpetlan@...hat.com>,
	Andi Kleen <ak@...ux.intel.com>,
	Jiapeng Chong <jiapeng.chong@...ux.alibaba.com>,
	Tiezhu Yang <yangtiezhu@...ngson.cn>,
	linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH v1 2/4] perf evsel: Missed close when probing hybrid core
 PMUs

On Mon, Jun 16, 2025 at 09:04:41AM -0700, Ian Rogers wrote:
> On Fri, Jun 13, 2025 at 5:41 PM Ian Rogers <irogers@...gle.com> wrote:
> > Add missing close to avoid leaking perf events. In past perfs this
> > mattered little as the function was just used by perf list. As the
> > function is now used to detect hybrid PMUs leaking the perf event is
> > somewhat more painful.
 
> Given this leads to leaking perf events on hybrid systems it would be
> nice to land this 1 liner in the next v6.15 rc pull request fixes if
> possible.

Sure.

Just one nit: while looking at:

void evsel__close(struct evsel *evsel)
{
        if (evsel__is_retire_lat(evsel))
                evsel__tpebs_close(evsel);
        perf_evsel__close(&evsel->core);
        perf_evsel__free_id(&evsel->core);
}

And then:

void evsel__delete(struct evsel *evsel)
{       
        if (!evsel)
                return;

        evsel__exit(evsel);
        free(evsel);
}

and:

void evsel__exit(struct evsel *evsel)
{       
        assert(list_empty(&evsel->core.node));
        assert(evsel->evlist == NULL);
        if (evsel__is_retire_lat(evsel))
                evsel__tpebs_close(evsel);
<SNIP>

I think that tpebs_close could be done just at evsel__close(), no?

The way it works I think there is no problem with calling it now twice,
but it fits better in evsel__close().

- Arnaldo