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[209.132.180.67]) by mx.google.com with ESMTP id h8si6002017pls.365.2019.02.18.11.06.49; Mon, 18 Feb 2019 11:07:04 -0800 (PST) Received-SPF: pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) client-ip=209.132.180.67; Authentication-Results: mx.google.com; dkim=fail header.i=@infradead.org header.s=bombadil.20170209 header.b=iKFMSAWo; spf=pass (google.com: best guess record for domain of linux-kernel-owner@vger.kernel.org designates 209.132.180.67 as permitted sender) smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2389311AbfBRRko (ORCPT + 99 others); Mon, 18 Feb 2019 12:40:44 -0500 Received: from bombadil.infradead.org ([198.137.202.133]:59114 "EHLO bombadil.infradead.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388727AbfBRRkd (ORCPT ); Mon, 18 Feb 2019 12:40:33 -0500 DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=bombadil.20170209; h=Content-Type:MIME-Version:References: Subject:Cc:To:From:Date:Message-Id:Sender:Reply-To:Content-Transfer-Encoding: Content-ID:Content-Description:Resent-Date:Resent-From:Resent-Sender: Resent-To:Resent-Cc:Resent-Message-ID:In-Reply-To:List-Id:List-Help: List-Unsubscribe:List-Subscribe:List-Post:List-Owner:List-Archive; bh=qa/iAb2+MKDNHlrJAJ7vmM6JHXm33Y4+EAhvheOGht8=; b=iKFMSAWo2IfZMZb3dKJOdGaIdP y0QTPESSqxkcsMb45rlkp2/5wcc7l/ut5RzJGOfi1s21DK2M1IA7658VuC1xuXVTlNksK5N/XfI4e Hpi9mm7BgrHWu0lQWV96p6PbVuRe9DLRtBjrE3fMkNbY46aXiKZTOrGKaVCW1TDqpdipoeCg/n/rE e0OoLNrln19PEsOt+sLQY+653CHrg9gv2XgC+XgY0Fn7iO3LL8+3DeuIuZ1psIGdHnI2n1Xs6iv3C SbZGml67A1xexOP27z5rK1uj7FsCAMQ5GhwlmgsYTHWX1mTbmpc3OgdJsz6fEdZNIqUVqv5QK8Fck TPwtDGDQ==; Received: from j217100.upc-j.chello.nl ([24.132.217.100] helo=hirez.programming.kicks-ass.net) by bombadil.infradead.org with esmtpsa (Exim 4.90_1 #2 (Red Hat Linux)) id 1gvmu4-0005zM-EO; Mon, 18 Feb 2019 17:40:28 +0000 Received: by hirez.programming.kicks-ass.net (Postfix, from userid 0) id 519EC2848B881; Mon, 18 Feb 2019 18:40:23 +0100 (CET) Message-Id: <20190218173514.796920915@infradead.org> User-Agent: quilt/0.65 Date: Mon, 18 Feb 2019 17:56:35 +0100 From: Peter Zijlstra To: mingo@kernel.org, tglx@linutronix.de, pjt@google.com, tim.c.chen@linux.intel.com, torvalds@linux-foundation.org Cc: linux-kernel@vger.kernel.org, subhra.mazumdar@oracle.com, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, "Peter Zijlstra (Intel)" Subject: [RFC][PATCH 15/16] sched: Trivial forced-newidle balancer References: <20190218165620.383905466@infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org When a sibling is forced-idle to match the core-cookie; search for matching tasks to fill the core. Signed-off-by: Peter Zijlstra (Intel) --- include/linux/sched.h | 1 kernel/sched/core.c | 131 +++++++++++++++++++++++++++++++++++++++++++++++++- kernel/sched/idle.c | 1 kernel/sched/sched.h | 6 ++ 4 files changed, 138 insertions(+), 1 deletion(-) --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -640,6 +640,7 @@ struct task_struct { #ifdef CONFIG_SCHED_CORE struct rb_node core_node; unsigned long core_cookie; + unsigned int core_occupation; #endif #ifdef CONFIG_CGROUP_SCHED --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -198,6 +198,21 @@ struct task_struct *sched_core_find(stru return match; } +struct task_struct *sched_core_next(struct task_struct *p, unsigned long cookie) +{ + struct rb_node *node = &p->core_node; + + node = rb_next(node); + if (!node) + return NULL; + + p = container_of(node, struct task_struct, core_node); + if (p->core_cookie != cookie) + return NULL; + + return p; +} + /* * The static-key + stop-machine variable are needed such that: * @@ -3650,7 +3665,7 @@ pick_next_task(struct rq *rq, struct tas struct task_struct *next, *max = NULL; const struct sched_class *class; const struct cpumask *smt_mask; - int i, j, cpu; + int i, j, cpu, occ = 0; if (!sched_core_enabled(rq)) return __pick_next_task(rq, prev, rf); @@ -3741,6 +3756,9 @@ pick_next_task(struct rq *rq, struct tas goto done; } + if (!is_idle_task(p)) + occ++; + rq_i->core_pick = p; /* @@ -3764,6 +3782,7 @@ pick_next_task(struct rq *rq, struct tas cpu_rq(j)->core_pick = NULL; } + occ = 1; goto again; } } @@ -3786,6 +3805,8 @@ next_class:; WARN_ON_ONCE(!rq_i->core_pick); + rq_i->core_pick->core_occupation = occ; + if (i == cpu) continue; @@ -3801,6 +3822,114 @@ next_class:; return next; } +static bool try_steal_cookie(int this, int that) +{ + struct rq *dst = cpu_rq(this), *src = cpu_rq(that); + struct task_struct *p; + unsigned long cookie; + bool success = false; + + local_irq_disable(); + double_rq_lock(dst, src); + + cookie = dst->core->core_cookie; + if (!cookie) + goto unlock; + + if (dst->curr != dst->idle) + goto unlock; + + p = sched_core_find(src, cookie); + if (p == src->idle) + goto unlock; + + do { + if (p == src->core_pick || p == src->curr) + goto next; + + if (!cpumask_test_cpu(this, &p->cpus_allowed)) + goto next; + + if (p->core_occupation > dst->idle->core_occupation) + goto next; + + p->on_rq = TASK_ON_RQ_MIGRATING; + deactivate_task(src, p, 0); + set_task_cpu(p, this); + activate_task(dst, p, 0); + p->on_rq = TASK_ON_RQ_QUEUED; + + resched_curr(dst); + + success = true; + break; + +next: + p = sched_core_next(p, cookie); + } while (p); + +unlock: + double_rq_unlock(dst, src); + local_irq_enable(); + + return success; +} + +static bool steal_cookie_task(int cpu, struct sched_domain *sd) +{ + int i; + + for_each_cpu_wrap(i, sched_domain_span(sd), cpu) { + if (i == cpu) + continue; + + if (need_resched()) + break; + + if (try_steal_cookie(cpu, i)) + return true; + } + + return false; +} + +static void sched_core_balance(struct rq *rq) +{ + struct sched_domain *sd; + int cpu = cpu_of(rq); + + rcu_read_lock(); + raw_spin_unlock_irq(rq_lockp(rq)); + for_each_domain(cpu, sd) { + if (!(sd->flags & SD_LOAD_BALANCE)) + break; + + if (need_resched()) + break; + + if (steal_cookie_task(cpu, sd)) + break; + } + raw_spin_lock_irq(rq_lockp(rq)); + rcu_read_unlock(); +} + +static DEFINE_PER_CPU(struct callback_head, core_balance_head); + +void queue_core_balance(struct rq *rq) +{ + if (!sched_core_enabled(rq)) + return; + + if (!rq->core->core_cookie) + return; + + if (!rq->nr_running) /* not forced idle */ + return; + + queue_balance_callback(rq, &per_cpu(core_balance_head, rq->cpu), sched_core_balance); +} + #else /* !CONFIG_SCHED_CORE */ static struct task_struct * --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -387,6 +387,7 @@ static void set_next_task_idle(struct rq { update_idle_core(rq); schedstat_inc(rq->sched_goidle); + queue_core_balance(rq); } static struct task_struct * --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1013,6 +1013,8 @@ static inline raw_spinlock_t *rq_lockp(s return &rq->__lock; } +extern void queue_core_balance(struct rq *rq); + #else /* !CONFIG_SCHED_CORE */ static inline bool sched_core_enabled(struct rq *rq) @@ -1025,6 +1027,10 @@ static inline raw_spinlock_t *rq_lockp(s return &rq->__lock; } +static inline void queue_core_balance(struct rq *rq) +{ +} + #endif /* CONFIG_SCHED_CORE */ #ifdef CONFIG_SCHED_SMT