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=-26.3 required=3.0 tests=BAYES_00,DKIMWL_WL_MED, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_CR_TRAILER,INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE, USER_AGENT_GIT,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 BB7AFC43600 for ; Thu, 20 May 2021 18:36:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A19A8610CC for ; Thu, 20 May 2021 18:36:38 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235690AbhETSh6 (ORCPT ); Thu, 20 May 2021 14:37:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:55490 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235582AbhETShs (ORCPT ); Thu, 20 May 2021 14:37:48 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B6F6BC061760 for ; Thu, 20 May 2021 11:36:26 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id o12-20020a5b050c0000b02904f4a117bd74so23688254ybp.17 for ; Thu, 20 May 2021 11:36:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20161025; h=date:in-reply-to:message-id:mime-version:references:subject:from:to :cc; bh=7AGHruEohYGhGsLWhPGwuum8o/o2x19SU6E/6s7D8Dk=; b=Pu3+Y7jvQGx8TOSMwAdcxkGXw8ApHel7a6gqUY+qKmkRatYgL7/OGgrzh2m84E1DuF HeS7fQ48lhl3lKTaB/4TDRHwRY4ZZoZMeaGAfiFRPyBXj9wrcf1QYW8duk7okWzIuP1f TxhGswAS6VSC1jKQ+4piAoSF+rVPKyRUOOaNiyAcFQLR+Fpal+Q8F+vn2TuvkucY5o5H u+djwx1e06pV5Qam34NLzSiMuFLlQOSRS3/d6hYA9O6O/ixjMemucKHZekx6vPmLzcvv pTS6/eoBxdtZk7V/T1yc7r8HH7/s+ZqV8lrl5tTavriQJ0614+wXkIySy3Lh6mzoEmdA GQYA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:date:in-reply-to:message-id:mime-version :references:subject:from:to:cc; bh=7AGHruEohYGhGsLWhPGwuum8o/o2x19SU6E/6s7D8Dk=; b=VF6aC+alP+tMBROkoS+YhbnB7HsM0sVn2lmRQV7uksClLg9iTHf+a+AS2oWHalrZwO Hy1hQCsscJnUqNKxdKB/cfqgL7BdAhr8CtCDV42eVKUSFZmA1uFhk1miY8ACQZuX8DKR Eqp6PutUwjLjzBQKeHzk6VLAfLSwLOXTa6RWEYdgBpx9D2NpoiqFBawL2v2I4US0tI/T nem863jh3P85yTMdwFs+qEQW+ttOKXxDx2spsd4V6LmTa/3UE73/bczAnUZ++mAh+e2h DYOpRJzVRhM98Ah4OvjxZEAp+e79tbnwVn+PN9dcC2NG3NmhL7p+9pEIe3sFId1dWZ3T LdmQ== X-Gm-Message-State: AOAM533aOCsfxztWzIL819KxRSy21PM/HQSemc9ilgwUMawGjNZDa3OY 6GWyoJxt93P9YH0YJXbE9bGBpFik X-Google-Smtp-Source: ABdhPJwZEzEbYEe6KExtIabrB2EPVXeZQ7vXbrODudHvRTn5hCfrxNnEWL2GkdoPkiN3kD73bJ9amJ9J X-Received: from posk.svl.corp.google.com ([2620:15c:2cd:202:f13e:18cf:76e6:2dc4]) (user=posk job=sendgmr) by 2002:a25:b6c6:: with SMTP id f6mr9686121ybm.16.1621535785956; Thu, 20 May 2021 11:36:25 -0700 (PDT) Date: Thu, 20 May 2021 11:36:08 -0700 In-Reply-To: <20210520183614.1227046-1-posk@google.com> Message-Id: <20210520183614.1227046-4-posk@google.com> Mime-Version: 1.0 References: <20210520183614.1227046-1-posk@google.com> X-Mailer: git-send-email 2.31.1.818.g46aad6cb9e-goog Subject: [RFC PATCH v0.1 3/9] sched: add WF_CURRENT_CPU and externise ttwu From: Peter Oskolkov To: Peter Zijlstra , Ingo Molnar , Thomas Gleixner , linux-kernel@vger.kernel.org, linux-api@vger.kernel.org Cc: Paul Turner , Ben Segall , Peter Oskolkov , Peter Oskolkov , Joel Fernandes , Andrew Morton , Andrei Vagin , Jim Newsome Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org 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 --- kernel/sched/core.c | 3 +-- kernel/sched/fair.c | 4 ++++ kernel/sched/sched.h | 15 +++++++++------ 3 files changed, 14 insertions(+), 8 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 3d2527239c3e..88506bc2617f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3683,8 +3683,7 @@ static void ttwu_queue(struct task_struct *p, int cpu, int wake_flags) * 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_flags) { unsigned long flags; int cpu, success = 0; diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 161b92aa1c79..e55256bbb60b 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6764,6 +6764,10 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int wake_flags) if (wake_flags & WF_TTWU) { record_wakee(p); + if ((wake_flags & WF_CURRENT_CPU) && + cpumask_test_cpu(cpu, p->cpus_ptr)) + return cpu; + if (sched_energy_enabled()) { new_cpu = find_energy_efficient_cpu(p, prev_cpu); if (new_cpu >= 0) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 8f0194cee0ba..205d05571d9e 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2027,13 +2027,14 @@ static inline int task_on_rq_migrating(struct task_struct *p) } /* 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 */ -#define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */ -#define WF_MIGRATED 0x20 /* Internal use, task got migrated */ -#define WF_ON_CPU 0x40 /* Wakee is on_cpu */ +#define WF_SYNC 0x10 /* Waker goes to sleep after wakeup */ +#define WF_MIGRATED 0x20 /* Internal use, task got migrated */ +#define WF_ON_CPU 0x40 /* Wakee is on_cpu */ +#define WF_CURRENT_CPU 0x80 /* Prefer to move the wakee to the current CPU. */ #ifdef CONFIG_SMP static_assert(WF_EXEC == SD_BALANCE_EXEC); @@ -3018,6 +3019,8 @@ static inline bool is_per_cpu_kthread(struct task_struct *p) extern void swake_up_all_locked(struct swait_queue_head *q); extern void __prepare_to_swait(struct swait_queue_head *q, struct swait_queue *wait); +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); -- 2.31.1.818.g46aad6cb9e-goog