From nobody Tue Dec 16 13:54:32 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 D870E3D3A0 for ; Wed, 21 Feb 2024 09:06:17 +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=1708506379; cv=none; b=A3EJSyW5mC/USX1/Mv3EFRiJSFP61jjgLOSN8FsASmSCosgiB1FvuPSTcJ/JJYTnVslMlc8gCJ2UReF6lDX8i9wEaLo+Qtu35yob7Iy5rAKBMtyhNFciEHOtJ7+bwnjmrCRllPZU5kOR1kGUYHR+myO5AU5vIFqV6hKh5xkb5m4= ARC-Message-Signature: i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1708506379; c=relaxed/simple; bh=fAB5xEIJhUT2xY7i5T7pqKYPBAt3GNmgTzm/jf5bOqc=; h=From:To:Cc:Subject:Date:Message-Id:In-Reply-To:References: MIME-Version; b=nPloMWIQcl+0i6pcCp1uSmpLkoV+3m1wRxuK9rgkEQDlSBe0BQxPoArVQBJL0Cc4LHRypgsVEtRASp9kfLJFru9/NFEM22cxoj6f0Ajui/aL9UumljXwUsC4FrbE3bD1ky7XzfHq4YQvHs2MwnAFWgIiQf9xPgj4EJkK0kqqIcM= 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=cxbjYNYY; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b=Sc1xvsMr; 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="cxbjYNYY"; dkim=permerror (0-bit key) header.d=linutronix.de header.i=@linutronix.de header.b="Sc1xvsMr" 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=QisrBEswo4w1Tqs9XJzYOTpU4VJaqEco1Cayy0t85z0=; b=cxbjYNYYvJE7nTIXnHt66nKWJdXP5gSGl1ZHzbW7WkQraHBGShczZFlaWC8cCHv0Nlal1u Fgamecy9zmNMhW2C0uGmgDvM69iP/PZMvYe2bvDUdZ08ArHoNyjsPaehvmFa/0QBvxF6iS xOUURNmNr2dh+yA2+0/MaUVZKJltKwceAY4+JdI1yCxjeo16RZRhbE9tH7KIV/PCW2YvZx sFQoYjOCGp/mMBCgUTlccfwSKqlvkWxIyO6PRn0Ic7SDK26DnHSkLJD2EXet6/LPX7QUZ7 riN0pjbWCiDzxPCOwMrkoQwFfaCn+onpcsvvD4zfpZdl997LzAQlqnAU5HHBXg== 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=QisrBEswo4w1Tqs9XJzYOTpU4VJaqEco1Cayy0t85z0=; b=Sc1xvsMrcCn5y3enYMmEDN21px5+dzmS0F3umaqNg/3PyQcflgyKmwhjWEo13yzGEfeU1K lFRuIkDk5XebubDQ== 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 05/20] timers: Introduce add_timer() variants which modify timer flags Date: Wed, 21 Feb 2024 10:05:33 +0100 Message-Id: <20240221090548.36600-6-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" A timer might be used as a pinned timer (using add_timer_on()) and later on as non-pinned timer using add_timer(). When the "NOHZ timer pull at expiry model" is in place, the TIMER_PINNED flag is required to be used whenever a timer needs to expire on a dedicated CPU. Otherwise the flag must not be set if expiration on a dedicated CPU is not required. add_timer_on()'s behavior will be changed during the preparation patches for the "NOHZ timer pull at expiry model" to unconditionally set TIMER_PINNED flag. To be able to clear/ set the flag when queueing a timer, two variants of add_timer() are introduced. This is a preparatory patch and has no functional change. Signed-off-by: Anna-Maria Behnsen Reviewed-by: Frederic Weisbecker --- v10: Commit message reworded as suggested by bigeasy v9: Update documentation to match kernel-doc style (missing brackets after function names) New in v6 --- include/linux/timer.h | 2 ++ kernel/time/timer.c | 34 ++++++++++++++++++++++++++++++++++ 2 files changed, 36 insertions(+) diff --git a/include/linux/timer.h b/include/linux/timer.h index f18a2f1eb79e..2be8be6dd317 100644 --- a/include/linux/timer.h +++ b/include/linux/timer.h @@ -165,6 +165,8 @@ extern int timer_reduce(struct timer_list *timer, unsig= ned long expires); #define NEXT_TIMER_MAX_DELTA ((1UL << 30) - 1) =20 extern void add_timer(struct timer_list *timer); +extern void add_timer_local(struct timer_list *timer); +extern void add_timer_global(struct timer_list *timer); =20 extern int try_to_del_timer_sync(struct timer_list *timer); extern int timer_delete_sync(struct timer_list *timer); diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 2f69a485a070..3cf016d6fa59 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -1245,6 +1245,40 @@ void add_timer(struct timer_list *timer) } EXPORT_SYMBOL(add_timer); =20 +/** + * add_timer_local() - Start a timer on the local CPU + * @timer: The timer to be started + * + * Same as add_timer() except that the timer flag TIMER_PINNED is set. + * + * See add_timer() for further details. + */ +void add_timer_local(struct timer_list *timer) +{ + if (WARN_ON_ONCE(timer_pending(timer))) + return; + timer->flags |=3D TIMER_PINNED; + __mod_timer(timer, timer->expires, MOD_TIMER_NOTPENDING); +} +EXPORT_SYMBOL(add_timer_local); + +/** + * add_timer_global() - Start a timer without TIMER_PINNED flag set + * @timer: The timer to be started + * + * Same as add_timer() except that the timer flag TIMER_PINNED is unset. + * + * See add_timer() for further details. + */ +void add_timer_global(struct timer_list *timer) +{ + if (WARN_ON_ONCE(timer_pending(timer))) + return; + timer->flags &=3D ~TIMER_PINNED; + __mod_timer(timer, timer->expires, MOD_TIMER_NOTPENDING); +} +EXPORT_SYMBOL(add_timer_global); + /** * add_timer_on - Start a timer on a particular CPU * @timer: The timer to be started --=20 2.39.2