linux-kernel - Re: [PATCH v3 02/22] perf cpumap: Use for each loop

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Message-ID: <YgaXEo6pOolljvo5@kernel.org>
Date:   Fri, 11 Feb 2022 14:04:18 -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>,
        Mark Rutland <mark.rutland@....com>,
        Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Jiri Olsa <jolsa@...nel.org>,
        Namhyung Kim <namhyung@...nel.org>,
        Thomas Gleixner <tglx@...utronix.de>,
        Darren Hart <dvhart@...radead.org>,
        Davidlohr Bueso <dave@...olabs.net>,
        André Almeida <andrealmeid@...labora.com>,
        James Clark <james.clark@....com>,
        John Garry <john.garry@...wei.com>,
        Riccardo Mancini <rickyman7@...il.com>,
        Yury Norov <yury.norov@...il.com>,
        Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Jin Yao <yao.jin@...ux.intel.com>,
        Adrian Hunter <adrian.hunter@...el.com>,
        Leo Yan <leo.yan@...aro.org>, Andi Kleen <ak@...ux.intel.com>,
        Thomas Richter <tmricht@...ux.ibm.com>,
        Kan Liang <kan.liang@...ux.intel.com>,
        Madhavan Srinivasan <maddy@...ux.ibm.com>,
        Shunsuke Nakamura <nakamura.shun@...itsu.com>,
        Song Liu <song@...nel.org>,
        Masami Hiramatsu <mhiramat@...nel.org>,
        Steven Rostedt <rostedt@...dmis.org>,
        Miaoqian Lin <linmq006@...il.com>,
        Stephen Brennan <stephen.s.brennan@...cle.com>,
        Kajol Jain <kjain@...ux.ibm.com>,
        Alexey Bayduraev <alexey.v.bayduraev@...ux.intel.com>,
        German Gomez <german.gomez@....com>,
        linux-perf-users@...r.kernel.org, linux-kernel@...r.kernel.org,
        Eric Dumazet <edumazet@...gle.com>,
        Dmitry Vyukov <dvyukov@...gle.com>,
        Hao Luo <haoluo@...gle.com>, eranian@...gle.com
Subject: Re: [PATCH v3 02/22] perf cpumap: Use for each loop

Em Fri, Feb 11, 2022 at 02:33:55AM -0800, Ian Rogers escreveu:
> Improve readability in perf_pmu__cpus_match by using
> perf_cpu_map__for_each_cpu.
> 
> Signed-off-by: Ian Rogers <irogers@...gle.com>
> ---
>  tools/perf/util/pmu.c | 14 ++++++--------
>  1 file changed, 6 insertions(+), 8 deletions(-)
> 
> diff --git a/tools/perf/util/pmu.c b/tools/perf/util/pmu.c
> index 8dfbba15aeb8..9a1c7e63e663 100644
> --- a/tools/perf/util/pmu.c
> +++ b/tools/perf/util/pmu.c
> @@ -1998,7 +1998,8 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
>  {
>  	struct perf_cpu_map *pmu_cpus = pmu->cpus;
>  	struct perf_cpu_map *matched_cpus, *unmatched_cpus;
> -	int matched_nr = 0, unmatched_nr = 0;
> +	struct perf_cpu cpu;
> +	int i, matched_nr = 0, unmatched_nr = 0;
>  
>  	matched_cpus = perf_cpu_map__default_new();
>  	if (!matched_cpus)
> @@ -2010,14 +2011,11 @@ int perf_pmu__cpus_match(struct perf_pmu *pmu, struct perf_cpu_map *cpus,
>  		return -1;
>  	}
>  
> -	for (int i = 0; i < cpus->nr; i++) {
> -		int cpu;
> -
> -		cpu = perf_cpu_map__idx(pmu_cpus, cpus->map[i]);
> -		if (cpu == -1)
> -			unmatched_cpus->map[unmatched_nr++] = cpus->map[i];
> +	perf_cpu_map__for_each_cpu(cpu, i, cpus) {

I'm applying this patch, but I wonder if we couldn't remove the need for
pre-declaring the integer iterator, so that the previous patch hunk
wouldn't be needed.

> +		if (!perf_cpu_map__has(pmu_cpus, cpu))
> +			unmatched_cpus->map[unmatched_nr++] = cpu;
>  		else
> -			matched_cpus->map[matched_nr++] = cpus->map[i];
> +			matched_cpus->map[matched_nr++] = cpu;
>  	}
>  
>  	unmatched_cpus->nr = unmatched_nr;
> -- 
> 2.35.1.265.g69c8d7142f-goog

-- 

- Arnaldo