From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 6A6211B951; Sun, 25 Feb 2024 22:21:42 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708899702; cv=none; b=bL6rU1K17YjfPfvzoCxe9I0tFRylbpm2abKACT0v06MEfF12a2wEjvwiI9VSfgjQyyBzYhFKPiN/3wT63kEVMpI0/rBHex84Vu4MVzMNzWLmSHJRcv6xvMTnJ4c+3Yp7rBd6Hty9wU1dzqLvV79i+4capa+RxwWn2Sc9hqpTtdw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708899702; c=relaxed/simple; bh=2rMIg+Hl+/TCyHRlXHHI/JIqctZyl4ljHu9l1dfMqOQ=; h=Date:From:To:Cc:Subject:Message-Id:In-Reply-To:References: Mime-Version:Content-Type; b=nV8kMmP4YOJOuXrnFqWf6CTKSy98Mva1RgbAPD+Ez548HCRio95roZyUq2GATsevGOTBKf7NBtidHemtsfHu1JAadrKTJvcGhON4CDZbydmjToCpNDtAOD8Z0+RXw0g/caj9TDHfAnH9bJLdN1vbZXmMJOZE21vfAz4fcdjSEK0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b=q53+PBEQ; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=kernel.org header.i=@kernel.org header.b="q53+PBEQ" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5FE8EC433F1; Sun, 25 Feb 2024 22:21:40 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1708899702; bh=2rMIg+Hl+/TCyHRlXHHI/JIqctZyl4ljHu9l1dfMqOQ=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=q53+PBEQmjWGHh/ZkfbNDHl4KdKn3K+mhvTZfd82oI/0uvrSWV6RK+yIH/BfoqkHq uVoyraL1pkW2HUmoq8XnpsxvhtJf4+V7AhAxgxg+ry0Zkz2WvDrRsSHu4F1aSzGR6Y WodeVCe+Dm94lgvRqjwhm6c2wkcwDLCLPYfnKFcRC1aqMZmf4Xhqw2nzS/MhgkQfsa vMHXuT91b84YbEeJqU3+YxQujEd4N5RuTIasZmptczveAtUZNSBDdfug0V2IjTHVLq N9kBrwW4KiLDZqyVwqMyKkRts5lBrr7NmHGOoz/dRat6eK7D1X3UBiTtv0Pu4fAztk WxHhAnW+a9jGA== Date: Mon, 26 Feb 2024 07:21:37 +0900 From: Masami Hiramatsu (Google) To: Thorsten Blum Cc: Steven Rostedt , Mathieu Desnoyers , linux-kernel@vger.kernel.org, linux-trace-kernel@vger.kernel.org Subject: Re: [PATCH] tracing: Use div64_u64() instead of do_div() Message-Id: <20240226072137.27e500b26ba2a7e1c42974f9@kernel.org> In-Reply-To: <20240225164507.232942-2-thorsten.blum@toblux.com> References: <20240225164507.232942-2-thorsten.blum@toblux.com> X-Mailer: Sylpheed 3.7.0 (GTK+ 2.24.33; x86_64-pc-linux-gnu) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit On Sun, 25 Feb 2024 17:45:08 +0100 Thorsten Blum 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) Thanks! > Signed-off-by: Thorsten Blum > --- > 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)