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=-18.8 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,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 34117C12002 for ; Fri, 16 Jul 2021 18:47:56 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 1E740613FE for ; Fri, 16 Jul 2021 18:47:56 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S232486AbhGPSut (ORCPT ); Fri, 16 Jul 2021 14:50:49 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:44576 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S232433AbhGPSuZ (ORCPT ); Fri, 16 Jul 2021 14:50:25 -0400 Received: from mail-pl1-x62c.google.com (mail-pl1-x62c.google.com [IPv6:2607:f8b0:4864:20::62c]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 2030BC061764 for ; Fri, 16 Jul 2021 11:47:30 -0700 (PDT) Received: by mail-pl1-x62c.google.com with SMTP id c15so5737087pls.13 for ; Fri, 16 Jul 2021 11:47:30 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=posk.io; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=vCPnqnwkhUpJbwG5YpNTPwxxCuigLKiLFFGzIuCOfoc=; b=Xuel8BK9JsT3L2fadBruunrxO49P35kg5RNBCg0ogtTinqX/RJNvnzFnTZZHdsxvTv cieo0jCkSbkd34c/34cvMMI5XZWfnCnwyaUQNqAdv7Z8b4UeURDCOFB6gsp+KGSFPNlc MkIVItmPHtqpZyY6QZ2C6DNLBVbwAWihtLzbLzl9u2dFDUSFDSGy01ytyCENwHeAwhm9 2pyhDK9cYvj6Z+AxzuoxtaSaNGU1YmtiLRME7rOFKPzP80nhXa/BF/UN0/7LEI3WR524 oiaDnXpVulzL9h0ve6OPCNE4ezgB8oXhWyGOjURYqN9fvPYCVABUauFtII34sdfZGc5n DIGg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=vCPnqnwkhUpJbwG5YpNTPwxxCuigLKiLFFGzIuCOfoc=; b=GdL4dt5ySCRGBJZDe11osUPhwYyPFNPYfpuLz11TISFxTzFaIopnuIkFmNEzjIJmGG piUzugP++0LeMgHed130siXRCgIF/NxZWN5FDI6Kxih6H+rTwWblnk8tIu4JvFaKfVN3 nlOZpxEVdYzJuH4jDVmfbdeoaa3rdQ0u5iA1VGom4RXPvi2lptWUv+2Z/e8Yo0sHVJm4 +3MbX+1SUrrf3t+lEICTSCzq+VJzDYdiKblYP0zyrf/NJFU1+hbrKBtsYX7pAXJFFKJp p/AOtMVxC83K0MJwqAFC8ea4RtWdeUCDkqPpwhvWvXZu3YXDCoLcQsEsZ4hMjpP3ZvfC pvbA== X-Gm-Message-State: AOAM533R9tVSB6BxZE6LY1PKpIedFmw5QMcNawI3UhyTOpqWVdVu+/mA AdqAaruwdLt7wJc/xk0hnsae8w== X-Google-Smtp-Source: ABdhPJxt2TQNSdsWaI/t/DNgYtWaN5Qcnj/3sv564RvLzubykA0Rrw0xlKr3H83D4N+nFSuuGMc1gQ== X-Received: by 2002:a17:90a:4cc4:: with SMTP id k62mr17035943pjh.110.1626461249673; Fri, 16 Jul 2021 11:47:29 -0700 (PDT) Received: from localhost.localdomain (23-118-52-46.lightspeed.sntcca.sbcglobal.net. [23.118.52.46]) by smtp.gmail.com with ESMTPSA id q125sm3170240pga.87.2021.07.16.11.47.28 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Fri, 16 Jul 2021 11:47:29 -0700 (PDT) From: Peter Oskolkov X-Google-Original-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 , Andrei Vagin , Jim Newsome , Jann Horn , Thierry Delisle Subject: [RFC PATCH 1/4 v0.3] sched: add WF_CURRENT_CPU and externise ttwu Date: Fri, 16 Jul 2021 11:47:16 -0700 Message-Id: <20210716184719.269033-2-posk@google.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210716184719.269033-1-posk@google.com> References: <20210716184719.269033-1-posk@google.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 0c22cd026440..293f5801bf81 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -3680,8 +3680,7 @@ 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 11d22943753f..16a9c93e6e82 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -6836,6 +6836,10 @@ 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 9a1c6aeb9165..80de6836f8ae 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2031,13 +2031,14 @@ 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); @@ -3037,6 +3038,8 @@ 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); -- 2.25.1