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=-9.8 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED, USER_AGENT_GIT 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 A448EC3F2D7 for ; Wed, 4 Mar 2020 17:00:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 71CE42465D for ; Wed, 4 Mar 2020 17:00:29 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=digitalocean.com header.i=@digitalocean.com header.b="VRArdCg2" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2388396AbgCDRAY (ORCPT ); Wed, 4 Mar 2020 12:00:24 -0500 Received: from mail-qv1-f66.google.com ([209.85.219.66]:43751 "EHLO mail-qv1-f66.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388359AbgCDRAT (ORCPT ); Wed, 4 Mar 2020 12:00:19 -0500 Received: by mail-qv1-f66.google.com with SMTP id eb12so1086167qvb.10 for ; Wed, 04 Mar 2020 09:00:18 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=digitalocean.com; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :in-reply-to:references; bh=sADPx7OazgDOOwf9vPVwiEhiMqBnjU05KKPLLLHmsf8=; b=VRArdCg2YbL7VSkoVn3asMtrVkek7/6ogjXXNu4ALg0abU/NZyc1hELW0vP/JxJmcq EvfrVHB+S6BC4wb8VJ6gmiUyTcyQAyDQpNdI9xsF2z/hNYLfmxTDv4q3tu/idjJs2Grf qU+rmkgN3qBFUbWzq5y18p7/TYSWBG3ivgdWc= 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:in-reply-to:references; bh=sADPx7OazgDOOwf9vPVwiEhiMqBnjU05KKPLLLHmsf8=; b=UXvwyR8/yzKbJPRyT7j2OcpEVATnisM508RmE4Hx/1cAmCCTDeKe10qR3F9jVQgjmM vRFlelwhm2ywJCXsvjb3x76FkGa1jhElYVCjx9NEqd3zXsX/OQzfR3MVwg1H5J8FZe2T sQ6t7qI/Uzhdaj1+vgk1MB/sAr/D64sfSRa/00pvJIeb+rNl3A91/BwZfF1F5goMO/MC /yn+yWh3Royjhic7T1J/6HLeFOzLBLTkUbTYO0JUyvYPLBVakW/eqsvPAwbCMGPT1diI RQnTnAPRFo4kPLEJh5AIo4oL0fW5HpnNe5fHAosNjRwkAbCMZ/FTaD2Hx/6C7LGEKtON 7B9Q== X-Gm-Message-State: ANhLgQ0gNpAmhgYOoeAjt/QYWGxbVa101sl/hmQOk/q0Sl7jJYLHnPHO ap/pQTH3wtBC8j8ze9xRVZ2HcfaOwjS7AA== X-Google-Smtp-Source: ADFU+vs5ogT/Xwifa7hgfLpnOGmo1RpXbpwRK/EwzRy2ca/Ybve+s+Kc2s55v7my6OuTei0vxntOdQ== X-Received: by 2002:a05:6214:907:: with SMTP id dj7mr2819421qvb.245.1583341217783; Wed, 04 Mar 2020 09:00:17 -0800 (PST) Received: from s2r5node9 ([162.243.188.99]) by smtp.gmail.com with ESMTPSA id t29sm15010113qtt.20.2020.03.04.09.00.17 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Wed, 04 Mar 2020 09:00:17 -0800 (PST) From: vpillai To: Nishanth Aravamudan , Julien Desfossez , Peter Zijlstra , Tim Chen , mingo@kernel.org, tglx@linutronix.de, pjt@google.com, torvalds@linux-foundation.org Cc: linux-kernel@vger.kernel.org, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, Phil Auld , Aaron Lu , Aubrey Li , aubrey.li@linux.intel.com, Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini , Joel Fernandes , joel@joelfernandes.org Subject: [RFC PATCH 10/13] sched: Trivial forced-newidle balancer Date: Wed, 4 Mar 2020 17:00:00 +0000 Message-Id: X-Mailer: git-send-email 2.17.1 In-Reply-To: References: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Peter Zijlstra 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(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index 80ec54706282..c9406a5b678f 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -685,6 +685,7 @@ 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 diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 556bf054b896..18ee8e10a171 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -218,6 +218,21 @@ static struct task_struct *sched_core_find(struct rq *rq, unsigned long cookie) return match; } +static 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: * @@ -4369,7 +4384,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) 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; bool need_sync = false; cpu = cpu_of(rq); @@ -4476,6 +4491,9 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) goto done; } + if (!is_idle_task(p)) + occ++; + rq_i->core_pick = p; /* @@ -4501,6 +4519,7 @@ pick_next_task(struct rq *rq, struct task_struct *prev, struct rq_flags *rf) cpu_rq(j)->core_pick = NULL; } + occ = 1; goto again; } else { /* @@ -4540,6 +4559,8 @@ next_class:; if (is_idle_task(rq_i->core_pick) && rq_i->nr_running) rq_i->core_forceidle = true; + rq_i->core_pick->core_occupation = occ; + if (i == cpu) continue; @@ -4555,6 +4576,114 @@ 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_mask)) + 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 * diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index 46c18e3dab13..b2f08431f0f1 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -395,6 +395,7 @@ static void set_next_task_idle(struct rq *rq, struct task_struct *next, bool fir { update_idle_core(rq); schedstat_inc(rq->sched_goidle); + queue_core_balance(rq); } static struct task_struct *pick_task_idle(struct rq *rq) diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index ef9e08e5da6a..552c80b70757 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1057,6 +1057,8 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) return &rq->__lock; } +extern void queue_core_balance(struct rq *rq); + void sched_core_add(struct rq *rq, struct task_struct *p); void sched_core_remove(struct rq *rq, struct task_struct *p); @@ -1072,6 +1074,10 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) return &rq->__lock; } +static inline void queue_core_balance(struct rq *rq) +{ +} + #endif /* CONFIG_SCHED_CORE */ #ifdef CONFIG_SCHED_SMT -- 2.17.1