From patchwork Mon Jul 25 13:34:19 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Morten Rasmussen X-Patchwork-Id: 72730 Delivered-To: patch@linaro.org Received: by 10.140.29.52 with SMTP id a49csp1152032qga; Mon, 25 Jul 2016 06:38:01 -0700 (PDT) X-Received: by 10.98.48.65 with SMTP id w62mr29568910pfw.18.1469453881312; Mon, 25 Jul 2016 06:38:01 -0700 (PDT) Return-Path: Received: from vger.kernel.org (vger.kernel.org. [209.132.180.67]) by mx.google.com with ESMTP id p64si33795997pfg.128.2016.07.25.06.38.01; Mon, 25 Jul 2016 06:38:01 -0700 (PDT) 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; 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 S1753135AbcGYNh6 (ORCPT + 29 others); Mon, 25 Jul 2016 09:37:58 -0400 Received: from foss.arm.com ([217.140.101.70]:33686 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752237AbcGYNfB (ORCPT ); Mon, 25 Jul 2016 09:35:01 -0400 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.72.51.249]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id C1C1D93D; Mon, 25 Jul 2016 06:36:15 -0700 (PDT) Received: from e105550-lin.cambridge.arm.com (e105550-lin.cambridge.arm.com [10.1.211.30]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id 3462F3F21A; Mon, 25 Jul 2016 06:34:59 -0700 (PDT) From: Morten Rasmussen To: peterz@infradead.org, mingo@redhat.com Cc: dietmar.eggemann@arm.com, yuyang.du@intel.com, vincent.guittot@linaro.org, mgalbraith@suse.de, sgurrappadi@nvidia.com, freedom.tan@mediatek.com, keita.kobayashi.ym@renesas.com, linux-kernel@vger.kernel.org, Morten Rasmussen , Rik van Riel Subject: [PATCH v3 02/13] sched/fair: Consistent use of prev_cpu in wakeup path Date: Mon, 25 Jul 2016 14:34:19 +0100 Message-Id: <1469453670-2660-3-git-send-email-morten.rasmussen@arm.com> X-Mailer: git-send-email 1.9.1 In-Reply-To: <1469453670-2660-1-git-send-email-morten.rasmussen@arm.com> References: <1469453670-2660-1-git-send-email-morten.rasmussen@arm.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In commit ac66f5477239 ("sched/numa: Introduce migrate_swap()") select_task_rq() got a 'cpu' argument to enable overriding of prev_cpu in special cases (NUMA task swapping). However, the select_task_rq_fair() helper functions: wake_affine() and select_idle_sibling(), still use task_cpu(p) directly to work out prev_cpu which leads to inconsistencies. This patch passes prev_cpu (potentially overridden by NUMA code) into the helper functions to ensure prev_cpu is indeed the same cpu everywhere in the wakeup path. cc: Ingo Molnar cc: Peter Zijlstra cc: Rik van Riel Signed-off-by: Morten Rasmussen --- kernel/sched/fair.c | 24 +++++++++++++----------- 1 file changed, 13 insertions(+), 11 deletions(-) -- 1.9.1 diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c index 4088eedea763..e7d50acd6028 100644 --- a/kernel/sched/fair.c +++ b/kernel/sched/fair.c @@ -656,7 +656,7 @@ static u64 sched_vslice(struct cfs_rq *cfs_rq, struct sched_entity *se) } #ifdef CONFIG_SMP -static int select_idle_sibling(struct task_struct *p, int cpu); +static int select_idle_sibling(struct task_struct *p, int prev_cpu, int cpu); static unsigned long task_h_load(struct task_struct *p); /* @@ -1514,7 +1514,8 @@ static void task_numa_compare(struct task_numa_env *env, * Call select_idle_sibling to maybe find a better one. */ if (!cur) - env->dst_cpu = select_idle_sibling(env->p, env->dst_cpu); + env->dst_cpu = select_idle_sibling(env->p, env->src_cpu, + env->dst_cpu); assign: task_numa_assign(env, cur, imp); @@ -5091,18 +5092,18 @@ static int wake_wide(struct task_struct *p) return 1; } -static int wake_affine(struct sched_domain *sd, struct task_struct *p, int sync) +static int wake_affine(struct sched_domain *sd, struct task_struct *p, + int prev_cpu, int sync) { s64 this_load, load; s64 this_eff_load, prev_eff_load; - int idx, this_cpu, prev_cpu; + int idx, this_cpu; struct task_group *tg; unsigned long weight; int balanced; idx = sd->wake_idx; this_cpu = smp_processor_id(); - prev_cpu = task_cpu(p); load = source_load(prev_cpu, idx); this_load = target_load(this_cpu, idx); @@ -5267,11 +5268,10 @@ find_idlest_cpu(struct sched_group *group, struct task_struct *p, int this_cpu) /* * Try and locate an idle CPU in the sched_domain. */ -static int select_idle_sibling(struct task_struct *p, int target) +static int select_idle_sibling(struct task_struct *p, int prev, int target) { struct sched_domain *sd; struct sched_group *sg; - int i = task_cpu(p); if (idle_cpu(target)) return target; @@ -5279,8 +5279,8 @@ static int select_idle_sibling(struct task_struct *p, int target) /* * If the prevous cpu is cache affine and idle, don't be stupid. */ - if (i != target && cpus_share_cache(i, target) && idle_cpu(i)) - return i; + if (prev != target && cpus_share_cache(prev, target) && idle_cpu(prev)) + return prev; /* * Otherwise, iterate the domains and find an eligible idle cpu. @@ -5301,6 +5301,8 @@ static int select_idle_sibling(struct task_struct *p, int target) for_each_lower_domain(sd) { sg = sd->groups; do { + int i; + if (!cpumask_intersects(sched_group_cpus(sg), tsk_cpus_allowed(p))) goto next; @@ -5409,13 +5411,13 @@ select_task_rq_fair(struct task_struct *p, int prev_cpu, int sd_flag, int wake_f if (affine_sd) { sd = NULL; /* Prefer wake_affine over balance flags */ - if (cpu != prev_cpu && wake_affine(affine_sd, p, sync)) + if (cpu != prev_cpu && wake_affine(affine_sd, p, prev_cpu, sync)) new_cpu = cpu; } if (!sd) { if (sd_flag & SD_BALANCE_WAKE) /* XXX always ? */ - new_cpu = select_idle_sibling(p, new_cpu); + new_cpu = select_idle_sibling(p, prev_cpu, new_cpu); } else while (sd) { struct sched_group *group;