Re: [PATCH 02/25] perf tools: Introduce xyarray__zero function

Arnaldo Carvalho de Melo
2015-06-10T19:06:08Z

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