linux-kernel - Re: [PATCH 5/8] perf tools: Detect missing kernel features properly

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Message-ID: <Zw9F0Ae_sWCVIEvu@google.com>
Date: Tue, 15 Oct 2024 21:49:20 -0700
From: Namhyung Kim <namhyung@...nel.org>
To: Ravi Bangoria <ravi.bangoria@....com>
Cc: Arnaldo Carvalho de Melo <acme@...nel.org>,
	Ian Rogers <irogers@...gle.com>,
	Kan Liang <kan.liang@...ux.intel.com>, Jiri Olsa <jolsa@...nel.org>,
	Adrian Hunter <adrian.hunter@...el.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Ingo Molnar <mingo@...nel.org>, LKML <linux-kernel@...r.kernel.org>,
	linux-perf-users@...r.kernel.org,
	Mark Rutland <mark.rutland@....com>,
	James Clark <james.clark@....com>, Kajol Jain <kjain@...ux.ibm.com>,
	Thomas Richter <tmricht@...ux.ibm.com>,
	Atish Patra <atishp@...shpatra.org>,
	Palmer Dabbelt <palmer@...osinc.com>,
	Mingwei Zhang <mizhang@...gle.com>
Subject: Re: [PATCH 5/8] perf tools: Detect missing kernel features properly

On Tue, Oct 15, 2024 at 09:49:52AM +0530, Ravi Bangoria wrote:
> > -	} else if (evsel->core.attr.exclude_guest || evsel->core.attr.exclude_host) {
> > -		if (evsel->pmu == NULL)
> > -			evsel->pmu = evsel__find_pmu(evsel);
> > -
> > -		if (evsel->pmu)
> > -			evsel->pmu->missing_features.exclude_guest = true;
> > -		else {
> > -			/* we cannot find PMU, disable attrs now */
> > -			evsel->core.attr.exclude_host = false;
> > -			evsel->core.attr.exclude_guest = false;
> > -		}
> >  
> > -		if (evsel->exclude_GH) {
> > -			pr_debug2_peo("PMU has no exclude_host/guest support, bailing out\n");
> > -			return false;
> > -		}
> > -		if (!perf_missing_features.exclude_guest) {
> > -			perf_missing_features.exclude_guest = true;
> > -			pr_debug2_peo("switching off exclude_guest, exclude_host\n");
> > -		}
> 
> Shall we get rid of:
> 
>   perf_missing_features.exclude_guest
>   pmu->missing_features.exclude_guest
> 
> they don't seem to be used anywhere after the patch.

Hmm.. it's my bad.  I think we should keep it for ancient kernels.

Thanks,
Namhyung