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 A3857FBF6 for ; Mon, 15 May 2023 17:56:28 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 06606C433D2; Mon, 15 May 2023 17:56:27 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1684173388; bh=mfpvP2kMpjsqrnywGnQtk/T1Asy2JIxAwVXTDRWh6LI=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=sXyWmAaicoxKG1qNeEyVZYzMlRXXeYRl49JYGbicQpILEQFxRAAVesgWH3dXIPEGA /r/AF0zob5Q/DA3nqndQ6857mIjQc8ZVa74N2twXuL69ZzUdhMsEDMVOnRPce8Alza PlvH7+WJEZZ1EKRg/Y99Ifgus+6ZL1dGduanhBVA= From: Greg Kroah-Hartman To: stable@vger.kernel.org Cc: Greg Kroah-Hartman , patches@lists.linux.dev, Thomas Gleixner , Sasha Levin Subject: [PATCH 5.4 071/282] tick/sched: Optimize tick_do_update_jiffies64() further Date: Mon, 15 May 2023 18:27:29 +0200 Message-Id: <20230515161724.361704409@linuxfoundation.org> X-Mailer: git-send-email 2.40.1 In-Reply-To: <20230515161722.146344674@linuxfoundation.org> References: <20230515161722.146344674@linuxfoundation.org> User-Agent: quilt/0.67 Precedence: bulk X-Mailing-List: patches@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit From: Thomas Gleixner [ Upstream commit 7a35bf2a6a871cd0252cd371d741e7d070b53af9 ] Now that it's clear that there is always one tick to account, simplify the calculations some more. Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20201117132006.565663056@linutronix.de Stable-dep-of: e9523a0d8189 ("tick/common: Align tick period with the HZ tick.") Signed-off-by: Sasha Levin --- kernel/time/tick-sched.c | 11 ++++++----- 1 file changed, 6 insertions(+), 5 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index eaeeb4bb1f8ab..3b00167656d78 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -53,7 +53,7 @@ static ktime_t last_jiffies_update; */ static void tick_do_update_jiffies64(ktime_t now) { - unsigned long ticks = 0; + unsigned long ticks = 1; ktime_t delta; /* @@ -91,20 +91,21 @@ static void tick_do_update_jiffies64(ktime_t now) write_seqcount_begin(&jiffies_seq); - last_jiffies_update = ktime_add(last_jiffies_update, tick_period); - delta = ktime_sub(now, tick_next_period); if (unlikely(delta >= tick_period)) { /* Slow path for long idle sleep times */ s64 incr = ktime_to_ns(tick_period); - ticks = ktime_divns(delta, incr); + ticks += ktime_divns(delta, incr); last_jiffies_update = ktime_add_ns(last_jiffies_update, incr * ticks); + } else { + last_jiffies_update = ktime_add(last_jiffies_update, + tick_period); } - do_timer(++ticks); + do_timer(ticks); /* * Keep the tick_next_period variable up to date. WRITE_ONCE() -- 2.39.2