From nobody Tue Dec 16 13:54:12 2025 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) (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 8D68D3D0B4 for ; Wed, 21 Feb 2024 09:06:16 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=193.142.43.55 ARC-Seal: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708506378; cv=none; b=MWgKu9LMEJHDy6uRQxViUyLk7zV59o+EpAJxujkbQ0yL8Tiw+liT7MSGT3jbzTR0BeOPW+hjoPr/ybLtjKZ/uz5SGoHibore1PqBxnYb341eA+WpaSoLv7rWQn/LEMA4Zm/4D349nKrLQoDjHd0lzRioqN+XZkjzOzN07o2ubZI= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708506378; c=relaxed/simple; bh=ws4UsvqTVPEJwlRcuRRnPZASwZHWSXxgj2cFVwZJl0g=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=VuhR7wKrB2ogeC8svnWDZA969Ac2KTroZ9zaZxUSqhD/zPTgReGocAlYgXsB2FPfvRyMyOKjN3YyYLWNJyRGrCjqI509gY6Np/VOOhsZt5Iq9ReenyFPbEDEA677Kzc3GLDKLcfy/aG2YgTShYpR82yoMmmIE+0PVr3D01Lb1I0= ARC-Authentication-Results: i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de; spf=pass smtp.mailfrom=linutronix.de; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Hx8+Knr8; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=tf7n+Sll; arc=none smtp.client-ip=193.142.43.55 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=linutronix.de Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=linutronix.de Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Hx8+Knr8"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="tf7n+Sll" From: Anna-Maria Behnsen DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1708506369; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8x8V66oedAQdLiHPaHBR+VdwFWZt1XkVYVwYivWxpoM=; b=Hx8+Knr8Z4dJ4chBC2NafZksHEPbKTCpR5IGhR5LRCe/JaVTRP1EVRAFVm/VJOl7MBivfe CPlw95EYEMRha70OszFXL+AVP8hFXZvntTYUYhybEgjSL5i3kmhQp7jFVcIZXwns/6tYGk q41Akso+7a0DWowVMQ3bmFU9ahEdtwN0UzW39j5mrSGuZrYeWnqnaMPlbWS3/e5rMXTftv vUPeQ9XL5zaV5IPOK+3s4AZJH2yqCvgWtbAoJ8ZbUQf2ROC3DW22hZe2oqukjmo/F3ggA6 Tncb3XnmNgp98CMmz3BrCv7Q9FsIO9MNd7eAnYKhhIOGIRlWbnXmRRiLeltMkw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1708506369; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=8x8V66oedAQdLiHPaHBR+VdwFWZt1XkVYVwYivWxpoM=; b=tf7n+SllvBHbEQu6a0UoCrngxBM8lQ8i8OnvMAJYCfZztbbKhMtwZZwKcgArYXicK4Ufuj Q4BGYcmQOmDy/TAw== To: linux-kernel@vger.kernel.org Cc: Peter Zijlstra , John Stultz , Thomas Gleixner , Eric Dumazet , "Rafael J . Wysocki" , Arjan van de Ven , "Paul E . McKenney" , Frederic Weisbecker , Rik van Riel , Steven Rostedt , Sebastian Siewior , Giovanni Gherdovich , Lukasz Luba , "Gautham R . Shenoy" , Srinivas Pandruvada , K Prateek Nayak , Christian Loehle , Anna-Maria Behnsen Subject: [PATCH v11 04/20] timers: Optimization for timer_base_try_to_set_idle() Date: Wed, 21 Feb 2024 10:05:32 +0100 Message-Id: <20240221090548.36600-5-anna-maria@linutronix.de> In-Reply-To: <20240221090548.36600-1-anna-maria@linutronix.de> References: <20240221090548.36600-1-anna-maria@linutronix.de> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Content-Type: text/plain; charset="utf-8" When tick is stopped also the timer base is_idle flag is set. When reentering the timer_base_try_to_set_idle() with the tick stopped, there is no need to check whether the timer base needs to be set idle again. When a timer was enqueued in the meantime, this is already handled by the tick_nohz_next_event() call which was executed before tick_nohz_stop_tick(). Signed-off-by: Anna-Maria Behnsen Reviewed-by: Frederic Weisbecker --- kernel/time/tick-sched.c | 2 +- kernel/time/timer.c | 11 ++++++++--- 2 files changed, 9 insertions(+), 4 deletions(-) diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index 72c80f6e7bed..384723314c1f 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -886,7 +886,7 @@ static void tick_nohz_stop_tick(struct tick_sched *ts, = int cpu) struct clock_event_device *dev =3D __this_cpu_read(tick_cpu_device.evtdev= ); unsigned long basejiff =3D ts->last_jiffies; u64 basemono =3D ts->timer_expires_base; - bool timer_idle; + bool timer_idle =3D ts->tick_stopped; u64 expires; =20 /* Make sure we won't be trying to stop it twice in a row. */ diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 3a668060692e..2f69a485a070 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1999,13 +1999,18 @@ u64 get_next_timer_interrupt(unsigned long basej, u= 64 basem) * timer_base_try_to_set_idle() - Try to set the idle state of the timer b= ases * @basej: base time jiffies * @basem: base time clock monotonic - * @idle: pointer to store the value of timer_base->is_idle + * @idle: pointer to store the value of timer_base->is_idle on return; + * *idle contains the information whether tick was already stopped * - * Returns the tick aligned clock monotonic time of the next pending - * timer or KTIME_MAX if no timer is pending. + * Returns the tick aligned clock monotonic time of the next pending timer= or + * KTIME_MAX if no timer is pending. When tick was already stopped KTIME_M= AX is + * returned as well. */ u64 timer_base_try_to_set_idle(unsigned long basej, u64 basem, bool *idle) { + if (*idle) + return KTIME_MAX; + return __get_next_timer_interrupt(basej, basem, idle); } =20 --=20 2.39.2