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Date: Fri, 26 Jun 2015 11:06:04 -0300
From: Arnaldo Carvalho de Melo <acme@kernel.org>
To: Jiri Olsa <jolsa@kernel.org>
Cc: lkml <linux-kernel@vger.kernel.org>,
        Adrian Hunter <adrian.hunter@intel.com>,
        Andi Kleen <ak@linux.intel.com>, David Ahern <dsahern@gmail.com>,
        Ingo Molnar <mingo@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
        Peter Zijlstra <a.p.zijlstra@chello.nl>,
        Stephane Eranian <eranian@google.com>
Subject: Re: [PATCH 01/22] perf thread_map: Introduce thread_map__reset
 function
Message-ID: <20150626140604.GB3265@kernel.org>
References: <1435310967-14570-1-git-send-email-jolsa@kernel.org>
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Em Fri, Jun 26, 2015 at 11:29:06AM +0200, Jiri Olsa escreveu:
> We need to reset newly allocated 'struct thread_map_data' entries,
> because we will introduce new comm memeber, which will get set
> later or not at all.

And this is an array that never shrinks, right?

At least current usage just makes it grow, ok.

- Arnaldo
 
> Link: http://lkml.kernel.org/n/tip-hg8xtux446qyjqkkcezwkg0v@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/util/thread_map.c | 17 ++++++++++++++++-
>  1 file changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/tools/perf/util/thread_map.c b/tools/perf/util/thread_map.c
> index 368cc58c6892..562e5e2c571c 100644
> --- a/tools/perf/util/thread_map.c
> +++ b/tools/perf/util/thread_map.c
> @@ -21,11 +21,26 @@ static int filter(const struct dirent *dir)
>  		return 1;
>  }
>  
> +static void thread_map__reset(struct thread_map *map, int start, int nr)
> +{
> +	size_t size = (nr - start) * sizeof(struct thread_map_data);
> +
> +	memset(&map->map[start], 0, size);
> +}
> +
>  static struct thread_map *thread_map__realloc(struct thread_map *map, int nr)
>  {
>  	size_t size = sizeof(*map) + sizeof(map->map[0]) * nr;
> +	int start = map ? map->nr : 0;
>  
> -	return realloc(map, size);
> +	map = realloc(map, size);
> +	/*
> +	 * We only realloc to add more items, let's reset new items.
> +	 */
> +	if (map)
> +		thread_map__reset(map, start, nr);
> +
> +	return map;
>  }
>  
>  #define thread_map__alloc(__nr) thread_map__realloc(NULL, __nr)
> -- 
> 1.9.3