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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,T_DKIMWL_WL_HIGH,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 909E1C28CC1 for ; Wed, 29 May 2019 20:37:23 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 543F92183F for ; Wed, 29 May 2019 20:37:23 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=digitalocean.com header.i=@digitalocean.com header.b="ByM7ru0f" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726877AbfE2UhW (ORCPT ); Wed, 29 May 2019 16:37:22 -0400 Received: from mail-it1-f194.google.com ([209.85.166.194]:51509 "EHLO mail-it1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726787AbfE2UhN (ORCPT ); Wed, 29 May 2019 16:37:13 -0400 Received: by mail-it1-f194.google.com with SMTP id m3so6276655itl.1 for ; Wed, 29 May 2019 13:37:12 -0700 (PDT) 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=PpmrO9QSzjOPZoRPgSbvtF4t4n5qN659GHtpQTPUio8=; b=ByM7ru0fShaA1rV89WRBqqlpBw3E0TXrDgzrwddMshQsmrU/WPq03xq7Mf58eA+jGX WDkrG3A79yclSVPlUYds+mHlQq58fWMBF1kSz8dtS8CtUnhHuWuJud+AetTzWmDARzRQ WhCw/DtS5ImIPW+bJv4/HXXWIft6o67y6GpR4= 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=PpmrO9QSzjOPZoRPgSbvtF4t4n5qN659GHtpQTPUio8=; b=hs6t+5lyHKxiMYTmnVygw3US7Kzy1eXy3rPPRtAVJ60iDgTAwqcMx7H5TmVWTr8Nm9 +frH+Cab055b6N3DT7GVAIVJjMc+n8sYe7oXRkfu1/YwJoNR95Z2A+rWdbhjhxTmAphb Fl9lcAU7dJl45aZivdjYrnN1Entw9Ufj8cUPdEaFQJLeGrXPfLmAnr+ytwXLZAS54dB0 Nc9NmBgw0B9BE2HhI48soWR0+B1vcSHQAWkssnSxDjT3AqXwNWSMclnGxIeiqAdMCuhP RULdQuemtYUv//qlpYzHHoQpucqCrDIv/YOGJaggWxcuIl/UhvHwFKiWUc9EYMncyBiU EmFA== X-Gm-Message-State: APjAAAVx/eUI8eoSCPUti4FlqXyWS+4MKAoa87RE76WwQT5ZmMe7ki5+ 7YXDc3GGLZcz6BjpqWEbHQxILA== X-Google-Smtp-Source: APXvYqwkbByxJ4oKotHMZXIyusSdhb2+tWL2GONVZluaT3z30NO37g1md4xvXjND2cp3Y4th3jfn0w== X-Received: by 2002:a24:27c6:: with SMTP id g189mr164783ita.114.1559162232136; Wed, 29 May 2019 13:37:12 -0700 (PDT) Received: from swap-tester ([178.128.225.14]) by smtp.gmail.com with ESMTPSA id e22sm175685iob.66.2019.05.29.13.37.11 (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Wed, 29 May 2019 13:37:11 -0700 (PDT) From: Vineeth Remanan Pillai 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, subhra.mazumdar@oracle.com, fweisbec@gmail.com, keescook@chromium.org, kerrnel@google.com, Phil Auld , Aaron Lu , Aubrey Li , Valentin Schneider , Mel Gorman , Pawan Gupta , Paolo Bonzini Subject: [RFC PATCH v3 15/16] sched: Trivial forced-newidle balancer Date: Wed, 29 May 2019 20:36:51 +0000 Message-Id: <011e60ed11ce980da400e4835a8994f9d98b134d.1559129225.git.vpillai@digitalocean.com> 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 a4b39a28236f..1a309e8546cd 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -641,6 +641,7 @@ 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 e25811b81562..5b8223c9a723 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -199,6 +199,21 @@ 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: * @@ -3672,7 +3687,7 @@ 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; if (!sched_core_enabled(rq)) @@ -3774,6 +3789,9 @@ 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; /* @@ -3799,6 +3817,7 @@ 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 { /* @@ -3838,6 +3857,8 @@ next_class:; if (is_idle_task(rq_i->core_pick) && rq_i->nr_running) rq->core_forceidle = true; + rq_i->core_pick->core_occupation = occ; + if (i == cpu) continue; @@ -3853,6 +3874,114 @@ 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 * diff --git a/kernel/sched/idle.c b/kernel/sched/idle.c index e7f38da60373..44decdcccba1 100644 --- a/kernel/sched/idle.c +++ b/kernel/sched/idle.c @@ -387,6 +387,7 @@ static void set_next_task_idle(struct rq *rq, struct task_struct *next) { update_idle_core(rq); schedstat_inc(rq->sched_goidle); + queue_core_balance(rq); } static struct task_struct * diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index cd8ced09826f..e91c188a452c 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -1014,6 +1014,8 @@ static inline raw_spinlock_t *rq_lockp(struct rq *rq) return &rq->__lock; } +extern void queue_core_balance(struct rq *rq); + #else /* !CONFIG_SCHED_CORE */ static inline bool sched_core_enabled(struct rq *rq) @@ -1026,6 +1028,10 @@ 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