From nobody Tue Apr 7 09:02:21 2026 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 E7FBEECAAD2 for ; Tue, 30 Aug 2022 01:44:46 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229852AbiH3Bog (ORCPT ); Mon, 29 Aug 2022 21:44:36 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:48604 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229602AbiH3BoI (ORCPT ); Mon, 29 Aug 2022 21:44:08 -0400 Received: from mail-pf1-x431.google.com (mail-pf1-x431.google.com [IPv6:2607:f8b0:4864:20::431]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id F0F7F7C305 for ; Mon, 29 Aug 2022 18:44:07 -0700 (PDT) Received: by mail-pf1-x431.google.com with SMTP id 145so9549500pfw.4 for ; Mon, 29 Aug 2022 18:44:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=G+5+t9wS3j8loUJEHuF9oZ643Kgj2nRnoYQ+cdIzE4Q=; b=p8rDSiod8Q6m2f7lk+vGYHRbMdp8G+R142a05Y91cEYOFDAIz4HqPR/p3gogUm0Ylz 5l58AwitYF7ClY7/r1uh90AHZqPulavtZLGuBk1pX+s1yUacjmsdsKZW9neSzre0hvZu Uqsfq7HgJLDLvNwr/UmZiExWBFqy8ePwhgbx3JfoKZJD7K6x9c+27IKwVKo7mLHeE7wG GQFB0gz0ZkrPU2pWnPg3Hut15UYaAuEwNO8/Xg08tn3wqAdJOGwrmqc0DyJLQZfr2pah +8nFLLbrjKfx/EsQNSPRF64j6afoBibu8dS6S/XrL3fnl1dAICEfbtwxZwqkWGxhZJJO QOBA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=G+5+t9wS3j8loUJEHuF9oZ643Kgj2nRnoYQ+cdIzE4Q=; b=J0EvrtehfgzIJNEBxlPl8fMoiou5m06tvza4cSp8RVLoVI17di5TgBRbno9iaI2CtU 4/VHcX3eNZX4OAghZbcctmpCa7k/g1VeAW+haE9zw6P3gWCaylqEIZtB6G1zesz/Fm2o uF5GFxn8cmc9eav3B2THxkdjgUlyos9r+0jvc7dzAcKm79tHPao/3gS+4RyiyMi1L0eM QwuZmPkkS7uPw8EFVO3qfoBwHo1CjEgmY1t5R8erLuJsx6EqB4NG7BImkAmWBKW/eGh7 J/2/xA8trnLj1q14oEXFFE0ZLfbo+1lF1nVzDoZMr2jPwx9oYogK4NvsPb318rGqo/qd xBOA== X-Gm-Message-State: ACgBeo15P2t2EAkEp6DZbbzPk3VOb3oYCJCuLf1s3Y8sI6DyZhKM1fTZ N3bcwPNO3fU9adWVvKvZAgDCOlKFHcQ= X-Google-Smtp-Source: AA6agR5h5y0JHFyZVNXdoeR4s3tDd2r5LXjhoA3xugPlUhw3wrPSh1KuENIbd4Gu1ZSwl/Dg+K4pyA== X-Received: by 2002:a65:494b:0:b0:428:d68c:35bf with SMTP id q11-20020a65494b000000b00428d68c35bfmr15539520pgs.509.1661823846843; Mon, 29 Aug 2022 18:44:06 -0700 (PDT) Received: from laptop.hsd1.wa.comcast.net ([2601:600:8500:5f14:d627:c51e:516e:a105]) by smtp.gmail.com with ESMTPSA id v14-20020aa799ce000000b00535faa9d6f2sm7976038pfi.53.2022.08.29.18.44.05 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 29 Aug 2022 18:44:06 -0700 (PDT) From: Andrei Vagin To: linux-kernel@vger.kernel.org Cc: Andrei Vagin , Andy Lutomirski , Christian Brauner , Dietmar Eggemann , Kees Cook , Ingo Molnar , Juri Lelli , Peter Oskolkov , Peter Zijlstra , Tycho Andersen , Will Drewry , Vincent Guittot Subject: [PATCH 2/4] sched: add WF_CURRENT_CPU and externise ttwu Date: Mon, 29 Aug 2022 18:43:54 -0700 Message-Id: <20220830014356.5364-3-avagin@gmail.com> X-Mailer: git-send-email 2.37.2 In-Reply-To: <20220830014356.5364-1-avagin@gmail.com> References: <20220830014356.5364-1-avagin@gmail.com> 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" From: Peter Oskolkov Add WF_CURRENT_CPU wake flag that advices the scheduler to move the wakee to the current CPU. This is useful for fast on-CPU context switching use cases such as UMCG. In addition, make ttwu external rather than static so that the flag could be passed to it from outside of sched/core.c. Signed-off-by: Peter Oskolkov Signed-off-by: Andrei Vagin --- kernel/sched/core.c | 3 +-- kernel/sched/fair.c | 4 ++++ kernel/sched/sched.h | 13 ++++++++----- 3 files changed, 13 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index ee28253c9ac0..008be12c31e6 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4045,8 +4045,7 @@ bool ttwu_state_match(struct task_struct *p, unsigned= int state, int *success) * Return: %true if @p->state changes (an actual wakeup was done), * %false otherwise. */ -static int -try_to_wake_up(struct task_struct *p, unsigned int state, int wake_flags) +int try_to_wake_up(struct task_struct *p, unsigned int state, int wake_fla= gs) { unsigned long flags; int cpu, success =3D 0; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 914096c5b1ae..7b043870b634 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -7028,6 +7028,10 @@ select_task_rq_fair(struct task_struct *p, int prev_= cpu, int wake_flags) if (wake_flags & WF_TTWU) { record_wakee(p); =20 + if ((wake_flags & WF_CURRENT_CPU) && + cpumask_test_cpu(cpu, p->cpus_ptr)) + return cpu; + if (sched_energy_enabled()) { new_cpu =3D find_energy_efficient_cpu(p, prev_cpu); if (new_cpu >=3D 0) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index e26688d387ae..6e93e8808bfd 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2080,12 +2080,13 @@ static inline int task_on_rq_migrating(struct task_= struct *p) } =20 /* Wake flags. The first three directly map to some SD flag value */ -#define WF_EXEC 0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC */ -#define WF_FORK 0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK */ -#define WF_TTWU 0x08 /* Wakeup; maps to SD_BALANCE_WAKE */ +#define WF_EXEC 0x02 /* Wakeup after exec; maps to SD_BALANCE_EXEC= */ +#define WF_FORK 0x04 /* Wakeup after fork; maps to SD_BALANCE_FORK= */ +#define WF_TTWU 0x08 /* Wakeup; maps to SD_BALANCE_WAKE= */ =20 -#define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */ -#define WF_MIGRATED 0x20 /* Internal use, task got migrated */ +#define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */ +#define WF_MIGRATED 0x20 /* Internal use, task got migrated */ +#define WF_CURRENT_CPU 0x40 /* Prefer to move the wakee to the current CP= U. */ =20 #ifdef CONFIG_SMP static_assert(WF_EXEC =3D=3D SD_BALANCE_EXEC); @@ -3151,6 +3152,8 @@ static inline bool is_per_cpu_kthread(struct task_str= uct *p) extern void swake_up_all_locked(struct swait_queue_head *q); extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_qu= eue *wait); =20 +extern int try_to_wake_up(struct task_struct *tsk, unsigned int state, int= wake_flags); + #ifdef CONFIG_PREEMPT_DYNAMIC extern int preempt_dynamic_mode; extern int sched_dynamic_mode(const char *str); --=20 2.37.2