linux-kernel - Re: [PATCH 1/2] perf: drop unneeded bitmap

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Date:   Tue, 24 Jul 2018 23:26:39 +0300
From:   Yury Norov <ynorov@...iumnetworks.com>
To:     Alexander Shishkin <alexander.shishkin@...ux.intel.com>,
        Peter Zijlstra <peterz@...radead.org>,
        Ingo Molnar <mingo@...hat.com>,
        Arnaldo Carvalho de Melo <acme@...nel.org>,
        Jiri Olsa <jolsa@...hat.com>,
        Namhyung Kim <namhyung@...nel.org>,
        Kate Stewart <kstewart@...uxfoundation.org>,
        Matthew Wilcox <willy@...radead.org>,
        Philippe Ombredanne <pombredanne@...b.com>,
        David Ahern <dsahern@...il.com>,
        David Carrillo-Cisneros <davidcc@...gle.com>,
        Andi Kleen <ak@...ux.intel.com>,
        Jin Yao <yao.jin@...ux.intel.com>, linux-kernel@...r.kernel.org
Cc:     Andy Shevchenko <andriy.shevchenko@...ux.intel.com>,
        Dmitry Torokhov <dmitry.torokhov@...il.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Mike Snitzer <snitzer@...hat.com>
Subject: Re: [PATCH 1/2] perf: drop unneeded bitmap_zero() in util/header.c

On Sat, Jun 23, 2018 at 10:35:01AM +0300, Yury Norov wrote:
> On top of next-20180622.
> 
> bitmap_zero() is called after bitmap_alloc() in perf code. But
> bitmap_alloc() internally uses calloc() which guarantees that allocated
> area is zeroed. So following bitmap_zero is unneeded. Drop it.
> 
> This happened because of confusing name for bitmap allocator. It
> should has name bitmap_zalloc instead of bitmap_alloc. This series:
> https://lkml.org/lkml/2018/6/18/841
> introduces new API for bitmap allocations in kernel, and functions
> there are named correctly. Following patch propogates the API to tools,
> and fixes naming issue.
> 
> Signed-off-by: Yury Norov <ynorov@...iumnetworks.com>

Ping?

> ---
>  tools/perf/tests/bitmap.c   | 2 --
>  tools/perf/tests/mem2node.c | 5 +----
>  tools/perf/util/header.c    | 3 ---
>  3 files changed, 1 insertion(+), 9 deletions(-)
> 
> diff --git a/tools/perf/tests/bitmap.c b/tools/perf/tests/bitmap.c
> index 47bedf25ba69..96e7fc1ad3f9 100644
> --- a/tools/perf/tests/bitmap.c
> +++ b/tools/perf/tests/bitmap.c
> @@ -16,8 +16,6 @@ static unsigned long *get_bitmap(const char *str, int nbits)
>  	bm = bitmap_alloc(nbits);
>  
>  	if (map && bm) {
> -		bitmap_zero(bm, nbits);
> -
>  		for (i = 0; i < map->nr; i++)
>  			set_bit(map->map[i], bm);
>  	}
> diff --git a/tools/perf/tests/mem2node.c b/tools/perf/tests/mem2node.c
> index 0c3c87f86e03..d8e3d49d3638 100644
> --- a/tools/perf/tests/mem2node.c
> +++ b/tools/perf/tests/mem2node.c
> @@ -24,11 +24,8 @@ static unsigned long *get_bitmap(const char *str, int nbits)
>  	bm = bitmap_alloc(nbits);
>  
>  	if (map && bm) {
> -		bitmap_zero(bm, nbits);
> -
> -		for (i = 0; i < map->nr; i++) {
> +		for (i = 0; i < map->nr; i++)
>  			set_bit(map->map[i], bm);
> -		}
>  	}
>  
>  	if (map)
> diff --git a/tools/perf/util/header.c b/tools/perf/util/header.c
> index 540cd2dcd3e7..3a6bec22baa3 100644
> --- a/tools/perf/util/header.c
> +++ b/tools/perf/util/header.c
> @@ -279,8 +279,6 @@ static int do_read_bitmap(struct feat_fd *ff, unsigned long **pset, u64 *psize)
>  	if (!set)
>  		return -ENOMEM;
>  
> -	bitmap_zero(set, size);
> -
>  	p = (u64 *) set;
>  
>  	for (i = 0; (u64) i < BITS_TO_U64(size); i++) {
> @@ -1285,7 +1283,6 @@ static int memory_node__read(struct memory_node *n, unsigned long idx)
>  		return -ENOMEM;
>  	}
>  
> -	bitmap_zero(n->set, size);
>  	n->node = idx;
>  	n->size = size;
>  
> -- 
> 2.17.1