From nobody Mon Dec 29 04:58:59 2025 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id A04ABC4167B for ; Fri, 1 Dec 2023 09:28:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1378154AbjLAJ14 (ORCPT ); Fri, 1 Dec 2023 04:27:56 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:54410 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378071AbjLAJ12 (ORCPT ); Fri, 1 Dec 2023 04:27:28 -0500 Received: from galois.linutronix.de (Galois.linutronix.de [193.142.43.55]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id CE00B173B for ; Fri, 1 Dec 2023 01:27:18 -0800 (PST) From: Anna-Maria Behnsen DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1701422837; 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=nS3of1gsjpadmlTzOeKtxhnS0y1kmX6N3aik41bHBiA=; b=jd8JdSo6RSMAzUQGD0eFZtqqXum4T5DNbkhKfHsGgfKrpZeYgvPMRbitqOvajGAVnOXjI6 CUwVNu95rNCy/L5GzK63NOh365EDVDrf9ayAK4msa7dXSpEa80xXUWomRi6duxWLFm+VbM qCr1hrcESNQGxbIdSVpGa6B5nMD7U+enDcqohqFlaqh/MYvEqE3lCzl2P2uDwny8GJ0pZb e+Y7Q5UkpxPIXt7kcmWi+U4AE9QBHs0PlQvwXPRBOBrT+RaB+0SEBxJG882s2281fx76As 0B3s31n61vB24z+VP0fxZkI3ZAtKnfsQ0JzpWsdc4wBnNvNXxSgu/bYlY0W5kw== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1701422837; 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=nS3of1gsjpadmlTzOeKtxhnS0y1kmX6N3aik41bHBiA=; b=XvAVoft42FnLB6t8nWzHoq+keWMNp0u+ZuAOQmacO5++zBupzj5qe3N+KJ0loGqLT7o1ZZ rrBvtWXBA6WYHMAg== 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 , Anna-Maria Behnsen Subject: [PATCH v9 16/32] timers: Optimization for timer_base_try_to_set_idle() Date: Fri, 1 Dec 2023 10:26:38 +0100 Message-Id: <20231201092654.34614-17-anna-maria@linutronix.de> In-Reply-To: <20231201092654.34614-1-anna-maria@linutronix.de> References: <20231201092654.34614-1-anna-maria@linutronix.de> MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 nohz_get_next_event() call which was executed before tick_nohz_stop_tick(). Signed-off-by: Anna-Maria Behnsen --- v9: New, as this optimization was splitted from the patch before. --- 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 3e1cdb7c6966..c6b415052c56 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 df6558f62e6f..177bcde8a2c0 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1996,13 +1996,18 @@ 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