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=-15.8 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 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 60C4AC433B4 for ; Thu, 22 Apr 2021 12:39:00 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 29D8A61164 for ; Thu, 22 Apr 2021 12:39:00 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S236656AbhDVMjd (ORCPT ); Thu, 22 Apr 2021 08:39:33 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40174 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236392AbhDVMiE (ORCPT ); Thu, 22 Apr 2021 08:38:04 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 3912DC06138E for ; Thu, 22 Apr 2021 05:37:26 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-ID:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:In-Reply-To; bh=bSgsxIb478eiV+qIDajoPxU1Jc9TIX4P9BTttgq1sN8=; b=NdgYFan1l8/2D1fCOAhG/86DIq jHSPTG00NAqgbVIn9zoRPMosbatIIWQHuVmEFZMOmw/97PbPJRJGSvi8SriFO3GIJ4/GyySJkUdP+ RCNF5p6iLRioizLoXZCeLWTUj4k7sBGcjjz18msow+rAZhlklkKDEYNQmS6WP5TE01fvO4zjh79cb qg+RyKPUkBwdgfNWtAaVdxzzFTbYzJVbAkv2qAL6O5u5huh+NDwPRjBooSpoiWtjUhIwGkD8p/TvS gvGbRq1k0+LOiXea5dcKAr9UlWL98zNZQ+Vv5GRyTeyvL6TfLavOfITEXnpfZiJH34NF077qT29Lv 47e2kfIw==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=noisy.programming.kicks-ass.net) by casper.infradead.org with esmtpsa (Exim 4.94 #2 (Red Hat Linux)) id 1lZYZM-000IDa-SP; Thu, 22 Apr 2021 12:36:36 +0000 Received: from hirez.programming.kicks-ass.net (hirez.programming.kicks-ass.net [192.168.1.225]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits)) (Client did not present a certificate) by noisy.programming.kicks-ass.net (Postfix) with ESMTPS id 7D069300326; Thu, 22 Apr 2021 14:35:22 +0200 (CEST) Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 70C2C2C67A905; Thu, 22 Apr 2021 14:35:20 +0200 (CEST) Message-ID: <20210422123308.919768100@infradead.org> User-Agent: quilt/0.66 Date: Thu, 22 Apr 2021 14:05:15 +0200 From: Peter Zijlstra To: joel@joelfernandes.org, chris.hyser@oracle.com, joshdon@google.com, mingo@kernel.org, vincent.guittot@linaro.org, valentin.schneider@arm.com, mgorman@suse.de Cc: linux-kernel@vger.kernel.org, peterz@infradead.org, tglx@linutronix.de Subject: [PATCH 16/19] sched: Trivial core scheduling cookie management References: <20210422120459.447350175@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In order to not have to use pid_struct, create a new, smaller, structure to manage task cookies for core scheduling. Signed-off-by: Peter Zijlstra (Intel) --- include/linux/sched.h | 6 ++ kernel/fork.c | 1 kernel/sched/Makefile | 1 kernel/sched/core.c | 7 +- kernel/sched/core_sched.c | 109 ++++++++++++++++++++++++++++++++++++++++++++++ kernel/sched/sched.h | 16 ++++++ 6 files changed, 137 insertions(+), 3 deletions(-) --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2170,4 +2170,10 @@ int sched_trace_rq_nr_running(struct rq const struct cpumask *sched_trace_rd_span(struct root_domain *rd); +#ifdef CONFIG_SCHED_CORE +extern void sched_core_free(struct task_struct *tsk); +#else +static inline void sched_core_free(struct task_struct *tsk) { } +#endif + #endif --- a/kernel/fork.c +++ b/kernel/fork.c @@ -737,6 +737,7 @@ void __put_task_struct(struct task_struc exit_creds(tsk); delayacct_tsk_free(tsk); put_signal_struct(tsk->signal); + sched_core_free(tsk); if (!profile_handoff_task(tsk)) free_task(tsk); --- a/kernel/sched/Makefile +++ b/kernel/sched/Makefile @@ -36,3 +36,4 @@ obj-$(CONFIG_CPU_FREQ_GOV_SCHEDUTIL) += obj-$(CONFIG_MEMBARRIER) += membarrier.o obj-$(CONFIG_CPU_ISOLATION) += isolation.o obj-$(CONFIG_PSI) += psi.o +obj-$(CONFIG_SCHED_CORE) += core_sched.o --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -157,7 +157,7 @@ static inline int rb_sched_core_cmp(cons return 0; } -static void sched_core_enqueue(struct rq *rq, struct task_struct *p) +void sched_core_enqueue(struct rq *rq, struct task_struct *p) { rq->core->core_task_seq++; @@ -167,14 +167,15 @@ static void sched_core_enqueue(struct rq rb_add(&p->core_node, &rq->core_tree, rb_sched_core_less); } -static void sched_core_dequeue(struct rq *rq, struct task_struct *p) +void sched_core_dequeue(struct rq *rq, struct task_struct *p) { rq->core->core_task_seq++; - if (!p->core_cookie) + if (!sched_core_enqueued(p)) return; rb_erase(&p->core_node, &rq->core_tree); + RB_CLEAR_NODE(&p->core_node); } /* --- /dev/null +++ b/kernel/sched/core_sched.c @@ -0,0 +1,109 @@ +// SPDX-License-Identifier: GPL-2.0-only + +#include "sched.h" + +/* + * A simple wrapper around refcount. An allocated sched_core_cookie's + * address is used to compute the cookie of the task. + */ +struct sched_core_cookie { + refcount_t refcnt; +}; + +unsigned long sched_core_alloc_cookie(void) +{ + struct sched_core_cookie *ck = kmalloc(sizeof(*ck), GFP_KERNEL); + if (!ck) + return 0; + + refcount_set(&ck->refcnt, 1); + sched_core_get(); + + return (unsigned long)ck; +} + +void sched_core_put_cookie(unsigned long cookie) +{ + struct sched_core_cookie *ptr = (void *)cookie; + + if (ptr && refcount_dec_and_test(&ptr->refcnt)) { + kfree(ptr); + sched_core_put(); + } +} + +unsigned long sched_core_get_cookie(unsigned long cookie) +{ + struct sched_core_cookie *ptr = (void *)cookie; + + if (ptr) + refcount_inc(&ptr->refcnt); + + return cookie; +} + +/* + * sched_core_update_cookie - replace the cookie on a task + * @p: the task to update + * @cookie: the new cookie + * + * Effectively exchange the task cookie; caller is responsible for lifetimes on + * both ends. + * + * Returns: the old cookie + */ +unsigned long sched_core_update_cookie(struct task_struct *p, unsigned long cookie) +{ + unsigned long old_cookie; + struct rq_flags rf; + struct rq *rq; + bool enqueued; + + rq = task_rq_lock(p, &rf); + + /* + * Since creating a cookie implies sched_core_get(), and we cannot set + * a cookie until after we've created it, similarly, we cannot destroy + * a cookie until after we've removed it, we must have core scheduling + * enabled here. + */ + SCHED_WARN_ON((p->core_cookie || cookie) && !sched_core_enabled(rq)); + + enqueued = sched_core_enqueued(p); + if (enqueued) + sched_core_dequeue(rq, p); + + old_cookie = p->core_cookie; + p->core_cookie = cookie; + + if (enqueued) + sched_core_enqueue(rq, p); + + /* + * If task is currently running, it may not be compatible anymore after + * the cookie change, so enter the scheduler on its CPU to schedule it + * away. + */ + if (task_running(rq, p)) + resched_curr(rq); + + task_rq_unlock(rq, p, &rf); + + return old_cookie; +} + +static unsigned long sched_core_clone_cookie(struct task_struct *p) +{ + unsigned long cookie, flags; + + raw_spin_lock_irqsave(&p->pi_lock, flags); + cookie = sched_core_get_cookie(p->core_cookie); + raw_spin_unlock_irqrestore(&p->pi_lock, flags); + + return cookie; +} + +void sched_core_free(struct task_struct *p) +{ + sched_core_put_cookie(p->core_cookie); +} --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1222,6 +1222,22 @@ static inline bool sched_group_cookie_ma extern void queue_core_balance(struct rq *rq); +static inline bool sched_core_enqueued(struct task_struct *p) +{ + return !RB_EMPTY_NODE(&p->core_node); +} + +extern void sched_core_enqueue(struct rq *rq, struct task_struct *p); +extern void sched_core_dequeue(struct rq *rq, struct task_struct *p); + +extern void sched_core_get(void); +extern void sched_core_put(void); + +extern unsigned long sched_core_alloc_cookie(void); +extern void sched_core_put_cookie(unsigned long cookie); +extern unsigned long sched_core_get_cookie(unsigned long cookie); +extern unsigned long sched_core_update_cookie(struct task_struct *p, unsigned long cookie); + #else /* !CONFIG_SCHED_CORE */ static inline bool sched_core_enabled(struct rq *rq)