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Date: Wed, 10 Jun 2015 16:06:00 -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 02/25] perf tools: Introduce xyarray__zero function
Message-ID: <20150610190600.GD3332@kernel.org>
References: <1433959858-31858-1-git-send-email-jolsa@kernel.org>
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Em Wed, Jun 10, 2015 at 08:10:35PM +0200, Jiri Olsa escreveu:
> To zero all the xyarray contents. It will be used
> in following patches.

I guess I would prefer xyarray__memset(), similar semantics as
'memset()', but I did a quick look and this is used in the kernel in
things like bitmap_zero() and wrappers to it have that semantic...

Interesting that we don't have anymore a bzero() like function, but
then, looking at 'man bzero':

----------------------------
CONFORMING TO

       4.3BSD.   This  function  is  deprecated  (marked  as  LEGACY  in
POSIX.1-2001): use memset(3) in new programs.  POSIX.1-2008 removes the
specification of bzero().

-----------------------------

Guess we should use 'xyarray__memset()', ok?

- Arnaldo
 
> Link: http://lkml.kernel.org/n/tip-bp8bcl46cav05xn0uacg7ytn@git.kernel.org
> Signed-off-by: Jiri Olsa <jolsa@kernel.org>
> ---
>  tools/perf/util/xyarray.c | 8 ++++++++
>  tools/perf/util/xyarray.h | 2 ++
>  2 files changed, 10 insertions(+)
> 
> diff --git a/tools/perf/util/xyarray.c b/tools/perf/util/xyarray.c
> index 22afbf6c536a..d0ca9ed5e7f2 100644
> --- a/tools/perf/util/xyarray.c
> +++ b/tools/perf/util/xyarray.c
> @@ -9,11 +9,19 @@ struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size)
>  	if (xy != NULL) {
>  		xy->entry_size = entry_size;
>  		xy->row_size   = row_size;
> +		xy->entries    = xlen * ylen;
>  	}
>  
>  	return xy;
>  }
>  
> +void xyarray__zero(struct xyarray *xy)
> +{
> +	size_t n = xy->entries * xy->entry_size;
> +
> +	memset(xy->contents, 0, n);
> +}
> +
>  void xyarray__delete(struct xyarray *xy)
>  {
>  	free(xy);
> diff --git a/tools/perf/util/xyarray.h b/tools/perf/util/xyarray.h
> index c488a07275dd..60cd80acdaa9 100644
> --- a/tools/perf/util/xyarray.h
> +++ b/tools/perf/util/xyarray.h
> @@ -6,11 +6,13 @@
>  struct xyarray {
>  	size_t row_size;
>  	size_t entry_size;
> +	size_t entries;
>  	char contents[];
>  };
>  
>  struct xyarray *xyarray__new(int xlen, int ylen, size_t entry_size);
>  void xyarray__delete(struct xyarray *xy);
> +void xyarray__zero(struct xyarray *xy);
>  
>  static inline void *xyarray__entry(struct xyarray *xy, int x, int y)
>  {
> -- 
> 1.9.3