From mboxrd@z Thu Jan 1 00:00:00 1970 From: "Srivatsa S. Bhat" Subject: [PATCH v5 12/45] sched/migration: Use raw_spin_lock/unlock since interrupts are already disabled Date: Tue, 22 Jan 2013 13:05:59 +0530 Message-ID: <20130122073557.13822.60411.stgit@srivatsabhat.in.ibm.com> References: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: rostedt@goodmis.org, wangyun@linux.vnet.ibm.com, xiaoguangrong@linux.vnet.ibm.com, rjw@sisk.pl, sbw@mit.edu, fweisbec@gmail.com, linux@arm.linux.org.uk, nikunj@linux.vnet.ibm.com, srivatsa.bhat@linux.vnet.ibm.com, linux-pm@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org, netdev@vger.kernel.org, linux-doc@vger.kernel.org, linux-kernel@vger.kernel.org To: tglx@linutronix.de, peterz@infradead.org, tj@kernel.org, oleg@redhat.com, paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au, mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org Return-path: In-Reply-To: <20130122073210.13822.50434.stgit@srivatsabhat.in.ibm.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org We need not use the raw_spin_lock_irqsave/restore primitives because all CPU_DYING notifiers run with interrupts disabled. So just use raw_spin_lock/unlock. Signed-off-by: Srivatsa S. Bhat --- kernel/sched/core.c | 12 +++++------- 1 file changed, 5 insertions(+), 7 deletions(-) diff --git a/kernel/sched/core.c b/kernel/sched/core.c index c1596ac..c2cec88 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -4869,9 +4869,7 @@ static void calc_load_migrate(struct rq *rq) * Migrate all tasks from the rq, sleeping tasks will be migrated by * try_to_wake_up()->select_task_rq(). * - * Called with rq->lock held even though we'er in stop_machine() and - * there's no concurrency possible, we hold the required locks anyway - * because of lock validation efforts. + * Called with rq->lock held. */ static void migrate_tasks(unsigned int dead_cpu) { @@ -4883,8 +4881,8 @@ static void migrate_tasks(unsigned int dead_cpu) * Fudge the rq selection such that the below task selection loop * doesn't get stuck on the currently eligible stop task. * - * We're currently inside stop_machine() and the rq is either stuck - * in the stop_machine_cpu_stop() loop, or we're executing this code, + * We're currently inside stop_one_cpu() and the rq is either stuck + * in the cpu_stopper_thread(), or we're executing this code, * either way we should never end up calling schedule() until we're * done here. */ @@ -5153,14 +5151,14 @@ migration_call(struct notifier_block *nfb, unsigned long action, void *hcpu) case CPU_DYING: sched_ttwu_pending(); /* Update our root-domain */ - raw_spin_lock_irqsave(&rq->lock, flags); + raw_spin_lock(&rq->lock); /* Interrupts already disabled */ if (rq->rd) { BUG_ON(!cpumask_test_cpu(cpu, rq->rd->span)); set_rq_offline(rq); } migrate_tasks(cpu); BUG_ON(rq->nr_running != 1); /* the migration thread */ - raw_spin_unlock_irqrestore(&rq->lock, flags); + raw_spin_unlock(&rq->lock); break; case CPU_DEAD: