From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754073AbbDBSrq (ORCPT ); Thu, 2 Apr 2015 14:47:46 -0400 Received: from terminus.zytor.com ([198.137.202.10]:37359 "EHLO terminus.zytor.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754054AbbDBSri (ORCPT ); Thu, 2 Apr 2015 14:47:38 -0400 Date: Thu, 2 Apr 2015 11:47:04 -0700 From: tip-bot for Juri Lelli Message-ID: Cc: linux-kernel@vger.kernel.org, juri.lelli@gmail.com, peterz@infradead.org, tglx@linutronix.de, juri.lelli@arm.com, mingo@kernel.org, hpa@zytor.com Reply-To: peterz@infradead.org, tglx@linutronix.de, juri.lelli@gmail.com, linux-kernel@vger.kernel.org, mingo@kernel.org, hpa@zytor.com, juri.lelli@arm.com In-Reply-To: <1427792017-7356-2-git-send-email-juri.lelli@arm.com> References: <1427792017-7356-2-git-send-email-juri.lelli@arm.com> To: linux-tip-commits@vger.kernel.org Subject: [tip:sched/core] sched/core: Check for available DL bandwidth in cpuset_cpu_inactive() Git-Commit-ID: 3c18d447b3b36a8d3c90dc37dfbd363cdb685d0a X-Mailer: tip-git-log-daemon Robot-ID: Robot-Unsubscribe: Contact to get blacklisted from these emails MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Content-Type: text/plain; charset=UTF-8 Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Commit-ID: 3c18d447b3b36a8d3c90dc37dfbd363cdb685d0a Gitweb: http://git.kernel.org/tip/3c18d447b3b36a8d3c90dc37dfbd363cdb685d0a Author: Juri Lelli AuthorDate: Tue, 31 Mar 2015 09:53:37 +0100 Committer: Ingo Molnar CommitDate: Thu, 2 Apr 2015 17:42:56 +0200 sched/core: Check for available DL bandwidth in cpuset_cpu_inactive() Hotplug operations are destructive w.r.t. cpusets. In case such an operation is performed on a CPU belonging to an exlusive cpuset, the DL bandwidth information associated with the corresponding root domain is gone even if the operation fails (in sched_cpu_inactive()). For this reason we need to move the check we currently have in sched_cpu_inactive() to cpuset_cpu_inactive() to prevent useless cpusets reconfiguration in the CPU_DOWN_FAILED path. Signed-off-by: Juri Lelli Signed-off-by: Peter Zijlstra (Intel) Cc: Juri Lelli Link: http://lkml.kernel.org/r/1427792017-7356-2-git-send-email-juri.lelli@arm.com Signed-off-by: Ingo Molnar --- kernel/sched/core.c | 56 ++++++++++++++++++++++++++--------------------------- 1 file changed, 28 insertions(+), 28 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 4c49e75..28b0d75 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -5337,36 +5337,13 @@ static int sched_cpu_active(struct notifier_block *nfb, static int sched_cpu_inactive(struct notifier_block *nfb, unsigned long action, void *hcpu) { - unsigned long flags; - long cpu = (long)hcpu; - struct dl_bw *dl_b; - switch (action & ~CPU_TASKS_FROZEN) { case CPU_DOWN_PREPARE: - set_cpu_active(cpu, false); - - /* explicitly allow suspend */ - if (!(action & CPU_TASKS_FROZEN)) { - bool overflow; - int cpus; - - rcu_read_lock_sched(); - dl_b = dl_bw_of(cpu); - - raw_spin_lock_irqsave(&dl_b->lock, flags); - cpus = dl_bw_cpus(cpu); - overflow = __dl_overflow(dl_b, cpus, 0, 0); - raw_spin_unlock_irqrestore(&dl_b->lock, flags); - - rcu_read_unlock_sched(); - - if (overflow) - return notifier_from_errno(-EBUSY); - } + set_cpu_active((long)hcpu, false); return NOTIFY_OK; + default: + return NOTIFY_DONE; } - - return NOTIFY_DONE; } static int __init migration_init(void) @@ -7006,7 +6983,6 @@ static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, */ case CPU_ONLINE: - case CPU_DOWN_FAILED: cpuset_update_active_cpus(true); break; default: @@ -7018,8 +6994,32 @@ static int cpuset_cpu_active(struct notifier_block *nfb, unsigned long action, static int cpuset_cpu_inactive(struct notifier_block *nfb, unsigned long action, void *hcpu) { - switch (action) { + unsigned long flags; + long cpu = (long)hcpu; + struct dl_bw *dl_b; + + switch (action & ~CPU_TASKS_FROZEN) { case CPU_DOWN_PREPARE: + /* explicitly allow suspend */ + if (!(action & CPU_TASKS_FROZEN)) { + bool overflow; + int cpus; + + rcu_read_lock_sched(); + dl_b = dl_bw_of(cpu); + + raw_spin_lock_irqsave(&dl_b->lock, flags); + cpus = dl_bw_cpus(cpu); + overflow = __dl_overflow(dl_b, cpus, 0, 0); + raw_spin_unlock_irqrestore(&dl_b->lock, flags); + + rcu_read_unlock_sched(); + + if (overflow) { + trace_printk("hotplug failed for cpu %lu", cpu); + return notifier_from_errno(-EBUSY); + } + } cpuset_update_active_cpus(false); break; case CPU_DOWN_PREPARE_FROZEN: