* [PATCH] tracing: Use div64_u64() instead of do_div()
@ 2024-02-25 16:45 Thorsten Blum
2024-02-25 22:21 ` Masami Hiramatsu
0 siblings, 1 reply; 2+ messages in thread
From: Thorsten Blum @ 2024-02-25 16:45 UTC (permalink / raw)
To: Steven Rostedt, Masami Hiramatsu
Cc: Mathieu Desnoyers, linux-kernel, linux-trace-kernel, Thorsten Blum
Fixes Coccinelle/coccicheck warnings reported by do_div.cocci.
Compared to do_div(), div64_u64() does not implicitly cast the divisor and
does not unnecessarily calculate the remainder.
Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
---
kernel/trace/trace_benchmark.c | 5 ++---
1 file changed, 2 insertions(+), 3 deletions(-)
diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
index 54d5fa35c90a..811b08439406 100644
--- a/kernel/trace/trace_benchmark.c
+++ b/kernel/trace/trace_benchmark.c
@@ -92,7 +92,6 @@ static void trace_do_benchmark(void)
bm_total += delta;
bm_totalsq += delta * delta;
-
if (bm_cnt > 1) {
/*
* Apply Welford's method to calculate standard deviation:
@@ -105,7 +104,7 @@ static void trace_do_benchmark(void)
stddev = 0;
delta = bm_total;
- do_div(delta, bm_cnt);
+ delta = div64_u64(delta, bm_cnt);
avg = delta;
if (stddev > 0) {
@@ -127,7 +126,7 @@ static void trace_do_benchmark(void)
seed = stddev;
if (!last_seed)
break;
- do_div(seed, last_seed);
+ seed = div64_u64(seed, last_seed);
seed += last_seed;
do_div(seed, 2);
} while (i++ < 10 && last_seed != seed);
--
2.43.2
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] tracing: Use div64_u64() instead of do_div()
2024-02-25 16:45 [PATCH] tracing: Use div64_u64() instead of do_div() Thorsten Blum
@ 2024-02-25 22:21 ` Masami Hiramatsu
0 siblings, 0 replies; 2+ messages in thread
From: Masami Hiramatsu @ 2024-02-25 22:21 UTC (permalink / raw)
To: Thorsten Blum
Cc: Steven Rostedt, Mathieu Desnoyers, linux-kernel, linux-trace-kernel
On Sun, 25 Feb 2024 17:45:08 +0100
Thorsten Blum <thorsten.blum@toblux.com> wrote:
> Fixes Coccinelle/coccicheck warnings reported by do_div.cocci.
>
> Compared to do_div(), div64_u64() does not implicitly cast the divisor and
> does not unnecessarily calculate the remainder.
>
Looks good to me.
Acked-by: Masami Hiramatsu (Google) <mhiramat@kernel.org>
Thanks!
> Signed-off-by: Thorsten Blum <thorsten.blum@toblux.com>
> ---
> kernel/trace/trace_benchmark.c | 5 ++---
> 1 file changed, 2 insertions(+), 3 deletions(-)
>
> diff --git a/kernel/trace/trace_benchmark.c b/kernel/trace/trace_benchmark.c
> index 54d5fa35c90a..811b08439406 100644
> --- a/kernel/trace/trace_benchmark.c
> +++ b/kernel/trace/trace_benchmark.c
> @@ -92,7 +92,6 @@ static void trace_do_benchmark(void)
> bm_total += delta;
> bm_totalsq += delta * delta;
>
> -
> if (bm_cnt > 1) {
> /*
> * Apply Welford's method to calculate standard deviation:
> @@ -105,7 +104,7 @@ static void trace_do_benchmark(void)
> stddev = 0;
>
> delta = bm_total;
> - do_div(delta, bm_cnt);
> + delta = div64_u64(delta, bm_cnt);
> avg = delta;
>
> if (stddev > 0) {
> @@ -127,7 +126,7 @@ static void trace_do_benchmark(void)
> seed = stddev;
> if (!last_seed)
> break;
> - do_div(seed, last_seed);
> + seed = div64_u64(seed, last_seed);
> seed += last_seed;
> do_div(seed, 2);
> } while (i++ < 10 && last_seed != seed);
> --
> 2.43.2
>
--
Masami Hiramatsu (Google) <mhiramat@kernel.org>
^ permalink raw reply [flat|nested] 2+ messages in thread
end of thread, other threads:[~2024-02-25 22:21 UTC | newest]
Thread overview: 2+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2024-02-25 16:45 [PATCH] tracing: Use div64_u64() instead of do_div() Thorsten Blum
2024-02-25 22:21 ` Masami Hiramatsu
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).