From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-20.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3DE37C47080 for ; Mon, 31 May 2021 16:57:02 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1A8BE6052B for ; Mon, 31 May 2021 16:57:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231219AbhEaQ6j (ORCPT ); Mon, 31 May 2021 12:58:39 -0400 Received: from Galois.linutronix.de ([193.142.43.55]:54964 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233831AbhEaPIl (ORCPT ); Mon, 31 May 2021 11:08:41 -0400 Date: Mon, 31 May 2021 15:06:59 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1622473620; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eJsc+fCoI7FcRfS0YrtvO77yKk0hWIfDD7peKlScexA=; b=xlGdC1uvYWM86q5GBNXoD6NgNEHwSRbYAXqfQnc7ob0eJS6XwtiLflYZo1+zW0IEGkt832 69VVos4xiWMOXC6XQ1cBL1XPnKD9iK7GX3TY07YAA/KYx4nA9ux5zxw7OQ/AnrsbdvO8fk exv3xtrzCt+jktqmZ74C/LvdISpceQ6nZQtXSWVnxl9y4+nkBWM+dWb1NI5EELmv4mFcYu QAYRT2fuojbXIdRNhZ7NdfEvsid5zTwd1ieioQAvjfBwZ8Uc8AgBo/9Z0SZVuBBcZMiqVJ 385k+VdcqWzEJhgrBREIceI6AHH9G9EKF4a20KMyMLqBrWIaDAfUQ/AvYIsKcQ== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1622473620; h=from:from:sender:sender:reply-to:reply-to:subject:subject:date:date: message-id:message-id:to:to:cc:cc:mime-version:mime-version: content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=eJsc+fCoI7FcRfS0YrtvO77yKk0hWIfDD7peKlScexA=; b=adF5jhDhgDRaK6clkpKjd15YV5bKu2e9JZW8aqGgoX5c5CjomypASzgL7L7KWIQ78GulPt bFXHQSiDoDDg9fDw== From: "tip-bot2 for Will Deacon" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: timers/core] tick/broadcast: Prefer per-cpu oneshot wakeup timers to broadcast Cc: Will Deacon , Thomas Gleixner , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210524221818.15850-4-will@kernel.org> References: <20210524221818.15850-4-will@kernel.org> MIME-Version: 1.0 Message-ID: <162247361943.29796.573636369763733195.tip-bot2@tip-bot2> Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org The following commit has been merged into the timers/core branch of tip: Commit-ID: c94a8537df12708cc03da9120c3c3561ae744ce1 Gitweb: https://git.kernel.org/tip/c94a8537df12708cc03da9120c3c3561ae744ce1 Author: Will Deacon AuthorDate: Mon, 24 May 2021 23:18:16 +01:00 Committer: Thomas Gleixner CommitterDate: Mon, 31 May 2021 17:04:45 +02:00 tick/broadcast: Prefer per-cpu oneshot wakeup timers to broadcast Some SoCs have two per-cpu timer implementations where the timer with the higher rating stops in deep idle (i.e. suffers from CLOCK_EVT_FEAT_C3STOP) but is otherwise preferable to the timer with the lower rating. In such a design, selecting the higher rated devices relies on a global broadcast timer and IPIs to wake up from deep idle states. To avoid the reliance on a global broadcast timer and also to reduce the overhead associated with the IPI wakeups, extend tick_install_broadcast_device() to manage per-cpu wakeup timers separately from the broadcast device. For now, these timers remain unused. Signed-off-by: Will Deacon Signed-off-by: Thomas Gleixner Link: https://lore.kernel.org/r/20210524221818.15850-4-will@kernel.org --- kernel/time/tick-broadcast.c | 59 ++++++++++++++++++++++++++++++++++- kernel/time/tick-common.c | 2 +- kernel/time/tick-internal.h | 4 +- 3 files changed, 61 insertions(+), 4 deletions(-) diff --git a/kernel/time/tick-broadcast.c b/kernel/time/tick-broadcast.c index f3f2f4b..0e9e06d 100644 --- a/kernel/time/tick-broadcast.c +++ b/kernel/time/tick-broadcast.c @@ -33,6 +33,8 @@ static int tick_broadcast_forced; static __cacheline_aligned_in_smp DEFINE_RAW_SPINLOCK(tick_broadcast_lock); #ifdef CONFIG_TICK_ONESHOT +static DEFINE_PER_CPU(struct clock_event_device *, tick_oneshot_wakeup_device); + static void tick_broadcast_setup_oneshot(struct clock_event_device *bc); static void tick_broadcast_clear_oneshot(int cpu); static void tick_resume_broadcast_oneshot(struct clock_event_device *bc); @@ -88,13 +90,65 @@ static bool tick_check_broadcast_device(struct clock_event_device *curdev, return !curdev || newdev->rating > curdev->rating; } +#ifdef CONFIG_TICK_ONESHOT +static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu) +{ + return per_cpu(tick_oneshot_wakeup_device, cpu); +} + +static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev, + int cpu) +{ + struct clock_event_device *curdev = tick_get_oneshot_wakeup_device(cpu); + + if (!newdev) + goto set_device; + + if ((newdev->features & CLOCK_EVT_FEAT_DUMMY) || + (newdev->features & CLOCK_EVT_FEAT_C3STOP)) + return false; + + if (!(newdev->features & CLOCK_EVT_FEAT_PERCPU) || + !(newdev->features & CLOCK_EVT_FEAT_ONESHOT)) + return false; + + if (!cpumask_equal(newdev->cpumask, cpumask_of(cpu))) + return false; + + if (curdev && newdev->rating <= curdev->rating) + return false; + + if (!try_module_get(newdev->owner)) + return false; + +set_device: + clockevents_exchange_device(curdev, newdev); + per_cpu(tick_oneshot_wakeup_device, cpu) = newdev; + return true; +} +#else +static struct clock_event_device *tick_get_oneshot_wakeup_device(int cpu) +{ + return NULL; +} + +static bool tick_set_oneshot_wakeup_device(struct clock_event_device *newdev, + int cpu) +{ + return false; +} +#endif + /* * Conditionally install/replace broadcast device */ -void tick_install_broadcast_device(struct clock_event_device *dev) +void tick_install_broadcast_device(struct clock_event_device *dev, int cpu) { struct clock_event_device *cur = tick_broadcast_device.evtdev; + if (tick_set_oneshot_wakeup_device(dev, cpu)) + return; + if (!tick_check_broadcast_device(cur, dev)) return; @@ -996,6 +1050,9 @@ void hotplug_cpu__broadcast_tick_pull(int deadcpu) */ static void tick_broadcast_oneshot_offline(unsigned int cpu) { + if (tick_get_oneshot_wakeup_device(cpu)) + tick_set_oneshot_wakeup_device(NULL, cpu); + /* * Clear the broadcast masks for the dead cpu, but do not stop * the broadcast device! diff --git a/kernel/time/tick-common.c b/kernel/time/tick-common.c index e15bc0e..d663249 100644 --- a/kernel/time/tick-common.c +++ b/kernel/time/tick-common.c @@ -373,7 +373,7 @@ out_bc: /* * Can the new device be used as a broadcast device ? */ - tick_install_broadcast_device(newdev); + tick_install_broadcast_device(newdev, cpu); } /** diff --git a/kernel/time/tick-internal.h b/kernel/time/tick-internal.h index 7a981c9..30c8963 100644 --- a/kernel/time/tick-internal.h +++ b/kernel/time/tick-internal.h @@ -61,7 +61,7 @@ extern ssize_t sysfs_get_uname(const char *buf, char *dst, size_t cnt); /* Broadcasting support */ # ifdef CONFIG_GENERIC_CLOCKEVENTS_BROADCAST extern int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu); -extern void tick_install_broadcast_device(struct clock_event_device *dev); +extern void tick_install_broadcast_device(struct clock_event_device *dev, int cpu); extern int tick_is_broadcast_device(struct clock_event_device *dev); extern void tick_suspend_broadcast(void); extern void tick_resume_broadcast(void); @@ -72,7 +72,7 @@ extern int tick_broadcast_update_freq(struct clock_event_device *dev, u32 freq); extern struct tick_device *tick_get_broadcast_device(void); extern struct cpumask *tick_get_broadcast_mask(void); # else /* !CONFIG_GENERIC_CLOCKEVENTS_BROADCAST: */ -static inline void tick_install_broadcast_device(struct clock_event_device *dev) { } +static inline void tick_install_broadcast_device(struct clock_event_device *dev, int cpu) { } static inline int tick_is_broadcast_device(struct clock_event_device *dev) { return 0; } static inline int tick_device_uses_broadcast(struct clock_event_device *dev, int cpu) { return 0; } static inline void tick_do_periodic_broadcast(struct clock_event_device *d) { }