From nobody Wed Sep 10 02:01:36 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 6316EE7B601 for ; Wed, 4 Oct 2023 12:36:11 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242528AbjJDMgM (ORCPT ); Wed, 4 Oct 2023 08:36:12 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39306 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242388AbjJDMfo (ORCPT ); Wed, 4 Oct 2023 08:35:44 -0400 Received: from galois.linutronix.de (Galois.linutronix.de [IPv6:2a0a:51c0:0:12e:550::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 405F0FE for ; Wed, 4 Oct 2023 05:35:37 -0700 (PDT) From: Anna-Maria Behnsen DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1696422935; 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=V2oLs1aq9wqZoLE3N9pO7i2Jg8pkH2UAvQ/YD0cSS3w=; b=ErrEdK5o4fLjNOKgR1xLbb+lqKbZXJX4q+elFfDJDA//0AWfEsqGosv6wzPLQwjZPQ7bKu zWclerP4eKvrN4mAIYaUqpyzZZHqL3ULIsjADaDkEZQTPZatbMvYgO6gVOk0DWtulh+hiU GZ9xGY/kz+d3oLfEO5rFjzToqXZxzcPYLsnkP0ogcZjQnM1MlWEjtFC/87/5gyYD+3H4HV 9cCtiBBH+mmNMHPfMPeKzVBiCB5JYYTJB1hJeHlKFIj/pFdZ9R0FwbTEaYWS0nVEh6+71u DoMpZ07XeR7/EWdlN1lUtXaQCqan+KMw8KWn/tGPKaixi0Gtonmqjo9qEYikPA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1696422935; 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=V2oLs1aq9wqZoLE3N9pO7i2Jg8pkH2UAvQ/YD0cSS3w=; b=GAjl7C54dXXudkkC69QtWxiFiXq0RXPiPnqm0zbhDHbxYRfSZfRqBLIwnbsd53fRUtFV5f a2BbuSzQvpntn3BA== 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 , Richard Cochran Subject: [PATCH v8 17/25] timer: Retrieve next expiry of pinned/non-pinned timers separately Date: Wed, 4 Oct 2023 14:34:46 +0200 Message-Id: <20231004123454.15691-18-anna-maria@linutronix.de> In-Reply-To: <20231004123454.15691-1-anna-maria@linutronix.de> References: <20231004123454.15691-1-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" For the conversion of the NOHZ timer placement to a pull at expiry time model it's required to have separate expiry times for the pinned and the non-pinned (movable) timers. Therefore struct timer_events is introduced. No functional change Originally-by: Richard Cochran (linutronix GmbH) Signed-off-by: Anna-Maria Behnsen Reviewed-by: Frederic Weisbecker --- kernel/time/timer.c | 48 ++++++++++++++++++++++++++++++++++----------- 1 file changed, 37 insertions(+), 11 deletions(-) diff --git a/kernel/time/timer.c b/kernel/time/timer.c index 1cd214c2f3f1..4230fc6fa1ed 100644 --- a/kernel/time/timer.c +++ b/kernel/time/timer.c @@ -221,6 +221,11 @@ struct timer_base { =20 static DEFINE_PER_CPU(struct timer_base, timer_bases[NR_BASES]); =20 +struct timer_events { + u64 local; + u64 global; +}; + #ifdef CONFIG_NO_HZ_COMMON =20 static DEFINE_STATIC_KEY_FALSE(timers_nohz_active); @@ -1971,9 +1976,10 @@ static unsigned long next_timer_interrupt(struct tim= er_base *base) return base->next_expiry; } =20 -static inline unsigned long __get_next_timer_interrupt(unsigned long basej, +static inline unsigned long __get_next_timer_interrupt(unsigned long basej= , u64 basem, struct timer_base *base_local, - struct timer_base *base_global) + struct timer_base *base_global, + struct timer_events *tevt) { unsigned long nextevt, nextevt_local, nextevt_global; bool local_first; @@ -1996,12 +2002,32 @@ static inline unsigned long __get_next_timer_interr= upt(unsigned long basej, =20 nextevt =3D local_first ? nextevt_local : nextevt_global; =20 - if (base_local->timers_pending || base_global->timers_pending) { + /* + * If the @nextevt is at max. one tick away, use @nextevt and store + * it in the local expiry value. The next global event is irrelevant in + * this case and can be left as KTIME_MAX. + */ + if (time_before_eq(nextevt, basej + 1)) { /* If we missed a tick already, force 0 delta */ if (time_before(nextevt, basej)) nextevt =3D basej; + tevt->local =3D basem + (u64)(nextevt - basej) * TICK_NSEC; + return tevt->local; } =20 + /* + * Update tevt->* values: + * + * If the local queue expires first, then the global event can + * be ignored. If the global queue is empty, nothing to do + * either. + */ + if (!local_first && base_global->timers_pending) + tevt->global =3D basem + (u64)(nextevt_global - basej) * TICK_NSEC; + + if (base_local->timers_pending) + tevt->local =3D basem + (u64)(nextevt_local - basej) * TICK_NSEC; + return nextevt; } =20 @@ -2015,16 +2041,15 @@ static inline unsigned long __get_next_timer_interr= upt(unsigned long basej, */ u64 get_next_timer_interrupt(unsigned long basej, u64 basem) { + struct timer_events tevt =3D { .local =3D KTIME_MAX, .global =3D KTIME_MA= X }; struct timer_base *base_local, *base_global; - u64 expires =3D KTIME_MAX; - unsigned long nextevt; =20 /* * Pretend that there is no timer pending if the cpu is offline. * Possible pending timers will be migrated later to an active cpu. */ if (cpu_is_offline(smp_processor_id())) - return expires; + return KTIME_MAX; =20 base_local =3D this_cpu_ptr(&timer_bases[BASE_LOCAL]); base_global =3D this_cpu_ptr(&timer_bases[BASE_GLOBAL]); @@ -2032,14 +2057,14 @@ u64 get_next_timer_interrupt(unsigned long basej, u= 64 basem) raw_spin_lock(&base_local->lock); raw_spin_lock_nested(&base_global->lock, SINGLE_DEPTH_NESTING); =20 - nextevt =3D __get_next_timer_interrupt(basej, base_local, base_global); + __get_next_timer_interrupt(basej, basem, base_local, base_global, &tevt); =20 raw_spin_unlock(&base_global->lock); raw_spin_unlock(&base_local->lock); =20 - expires =3D basem + (u64)(nextevt - basej) * TICK_NSEC; + tevt.local =3D min_t(u64, tevt.local, tevt.global); =20 - return cmp_next_hrtimer_event(basem, expires); + return cmp_next_hrtimer_event(basem, tevt.local); } =20 /** @@ -2055,6 +2080,7 @@ u64 get_next_timer_interrupt(unsigned long basej, u64= basem) */ u64 timer_set_idle(unsigned long basej, u64 basem, bool *idle) { + struct timer_events tevt =3D { .local =3D KTIME_MAX, .global =3D KTIME_MA= X }; struct timer_base *base_local, *base_global; unsigned long nextevt; =20 @@ -2073,7 +2099,7 @@ u64 timer_set_idle(unsigned long basej, u64 basem, bo= ol *idle) raw_spin_lock(&base_local->lock); raw_spin_lock_nested(&base_global->lock, SINGLE_DEPTH_NESTING); =20 - nextevt =3D __get_next_timer_interrupt(basej, base_local, base_global); + nextevt =3D __get_next_timer_interrupt(basej, basem, base_local, base_glo= bal, &tevt); =20 /* * We have a fresh next event. Check whether we can forward the @@ -2097,7 +2123,7 @@ u64 timer_set_idle(unsigned long basej, u64 basem, bo= ol *idle) raw_spin_unlock(&base_global->lock); raw_spin_unlock(&base_local->lock); =20 - return basem + (u64)(nextevt - basej) * TICK_NSEC; + return min_t(u64, tevt.local, tevt.global); } =20 /** --=20 2.39.2