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=-20.7 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 D02B1C432C3 for ; Tue, 2 Mar 2021 09:35:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A267F60200 for ; Tue, 2 Mar 2021 09:35:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382358AbhCBJZ1 (ORCPT ); Tue, 2 Mar 2021 04:25:27 -0500 Received: from Galois.linutronix.de ([193.142.43.55]:35668 "EHLO galois.linutronix.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1378832AbhCBJD0 (ORCPT ); Tue, 2 Mar 2021 04:03:26 -0500 Date: Tue, 02 Mar 2021 09:01:54 -0000 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020; t=1614675715; 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=rQqqAUTPo2dYbb3X9g5nIQAMGcVCpCBWOGBwlnT00TQ=; b=yltV/SkICtD5kgoXqcbHD7q8vg9LyylU19yaTXBKYKraS7Bsosyw1if8syz6oa6MDcwZLs RMAQsb57vwlgTdpo74Op6o/RA+Vlj+ilGx5uVdDlQtH13GOdtObR9n4VzzrSlEZ/uao1Q3 VsyjDBEyA6k9cwmmO5Ssj2qptX3DAqGHGn2y5TZKo3RA7zcMbC5IGj4nwmPPDHFb0PZtks sR/fedAJXEcZy1AH7YiebD9mbKdnqzfdmKdpx+mbl2J6B1X1BRLdwpGuX75smIhTXH3S7a rjTu03A+ja9anrtxy77MDYHmXT4GznMVdaxW1ZT7ozyJzPh1UXEGlQt0EB5GfA== DKIM-Signature: v=1; a=ed25519-sha256; c=relaxed/relaxed; d=linutronix.de; s=2020e; t=1614675715; 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=rQqqAUTPo2dYbb3X9g5nIQAMGcVCpCBWOGBwlnT00TQ=; b=oea+m/y55jkMId8iCamacTe0xIOrIA9dgKM3yt2YS71M5RehNVqPBL0D4/h6BGeWIxSlWu O5JUDa3kCqBXyxCg== From: "tip-bot2 for Vincent Guittot" Sender: tip-bot2@linutronix.de Reply-to: linux-kernel@vger.kernel.org To: linux-tip-commits@vger.kernel.org Subject: [tip: sched/core] sched/fair: Trigger the update of blocked load on newly idle cpu Cc: Vincent Guittot , "Peter Zijlstra (Intel)" , Valentin Schneider , x86@kernel.org, linux-kernel@vger.kernel.org In-Reply-To: <20210224133007.28644-7-vincent.guittot@linaro.org> References: <20210224133007.28644-7-vincent.guittot@linaro.org> MIME-Version: 1.0 Message-ID: <161467571458.20312.9603244485224907644.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 sched/core branch of tip: Commit-ID: 1705e3b449f62d957e897239ef6c67ca574acfc6 Gitweb: https://git.kernel.org/tip/1705e3b449f62d957e897239ef6c67ca574acfc6 Author: Vincent Guittot AuthorDate: Wed, 24 Feb 2021 14:30:06 +01:00 Committer: Peter Zijlstra CommitterDate: Mon, 01 Mar 2021 18:17:24 +01:00 sched/fair: Trigger the update of blocked load on newly idle cpu Instead of waking up a random and already idle CPU, we can take advantage of this_cpu being about to enter idle to run the ILB and update the blocked load. Signed-off-by: Vincent Guittot Signed-off-by: Peter Zijlstra (Intel) Reviewed-by: Valentin Schneider Link: https://lkml.kernel.org/r/20210224133007.28644-7-vincent.guittot@linaro.org --- kernel/sched/core.c | 2 +- kernel/sched/fair.c | 24 +++++++++++++++++++++--- kernel/sched/idle.c | 6 ++++++ kernel/sched/sched.h | 7 +++++++ 4 files changed, 35 insertions(+), 4 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index f9dfb34..361974e 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -737,7 +737,7 @@ static void nohz_csd_func(void *info) /* * Release the rq::nohz_csd. */ - flags = atomic_fetch_andnot(NOHZ_KICK_MASK, nohz_flags(cpu)); + flags = atomic_fetch_andnot(NOHZ_KICK_MASK | NOHZ_NEWILB_KICK, nohz_flags(cpu)); WARN_ON(!(flags & NOHZ_KICK_MASK)); rq->idle_balance = idle_cpu(cpu); diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 356a245..e87e1b3 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -10453,6 +10453,24 @@ static bool nohz_idle_balance(struct rq *this_rq, enum cpu_idle_type idle) return true; } +/* + * Check if we need to run the ILB for updating blocked load before entering + * idle state. + */ +void nohz_run_idle_balance(int cpu) +{ + unsigned int flags; + + flags = atomic_fetch_andnot(NOHZ_NEWILB_KICK, nohz_flags(cpu)); + + /* + * Update the blocked load only if no SCHED_SOFTIRQ is about to happen + * (ie NOHZ_STATS_KICK set) and will do the same. + */ + if ((flags == NOHZ_NEWILB_KICK) && !need_resched()) + _nohz_idle_balance(cpu_rq(cpu), NOHZ_STATS_KICK, CPU_IDLE); +} + static void nohz_newidle_balance(struct rq *this_rq) { int this_cpu = this_rq->cpu; @@ -10474,10 +10492,10 @@ static void nohz_newidle_balance(struct rq *this_rq) return; /* - * Blocked load of idle CPUs need to be updated. - * Kick an ILB to update statistics. + * Set the need to trigger ILB in order to update blocked load + * before entering idle state. */ - kick_ilb(NOHZ_STATS_KICK); + atomic_or(NOHZ_NEWILB_KICK, nohz_flags(this_cpu)); } #else /* !CONFIG_NO_HZ_COMMON */ diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 7199e6f..7a92d60 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -261,6 +261,12 @@ exit_idle: static void do_idle(void) { int cpu = smp_processor_id(); + + /* + * Check if we need to update blocked load + */ + nohz_run_idle_balance(cpu); + /* * If the arch has a polling bit, we maintain an invariant: * diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 10a1522..0ddc9a6 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2385,9 +2385,11 @@ extern void cfs_bandwidth_usage_dec(void); #ifdef CONFIG_NO_HZ_COMMON #define NOHZ_BALANCE_KICK_BIT 0 #define NOHZ_STATS_KICK_BIT 1 +#define NOHZ_NEWILB_KICK_BIT 2 #define NOHZ_BALANCE_KICK BIT(NOHZ_BALANCE_KICK_BIT) #define NOHZ_STATS_KICK BIT(NOHZ_STATS_KICK_BIT) +#define NOHZ_NEWILB_KICK BIT(NOHZ_NEWILB_KICK_BIT) #define NOHZ_KICK_MASK (NOHZ_BALANCE_KICK | NOHZ_STATS_KICK) @@ -2398,6 +2400,11 @@ extern void nohz_balance_exit_idle(struct rq *rq); static inline void nohz_balance_exit_idle(struct rq *rq) { } #endif +#if defined(CONFIG_SMP) && defined(CONFIG_NO_HZ_COMMON) +extern void nohz_run_idle_balance(int cpu); +#else +static inline void nohz_run_idle_balance(int cpu) { } +#endif #ifdef CONFIG_SMP static inline