From: "Srivatsa S. Bhat" <srivatsa.bhat@linux.vnet.ibm.com>
To: tglx@linutronix.de, peterz@infradead.org,
paulmck@linux.vnet.ibm.com, rusty@rustcorp.com.au,
mingo@kernel.org, akpm@linux-foundation.org, namhyung@kernel.org,
vincent.guittot@linaro.org
Cc: sbw@mit.edu, tj@kernel.org, amit.kucheria@linaro.org,
rostedt@goodmis.org, rjw@sisk.pl,
srivatsa.bhat@linux.vnet.ibm.com, wangyun@linux.vnet.ibm.com,
xiaoguangrong@linux.vnet.ibm.com, nikunj@linux.vnet.ibm.com,
linux-pm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [RFC PATCH 05/10] kick_process(), cpu-hotplug: Prevent offlining of target CPU properly
Date: Tue, 04 Dec 2012 14:25:06 +0530 [thread overview]
Message-ID: <20121204085504.25919.38913.stgit@srivatsabhat.in.ibm.com> (raw)
In-Reply-To: <20121204085149.25919.29920.stgit@srivatsabhat.in.ibm.com>
With stop_machine() gone from the CPU offline path, we can't depend on
preempt_disable() to prevent CPUs from going offline from under us.
Use the get/put_online_cpus_stable_atomic() APIs to prevent CPUs from going
offline, while invoking from atomic context.
Signed-off-by: Srivatsa S. Bhat <srivatsa.bhat@linux.vnet.ibm.com>
---
kernel/sched/core.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index ef6ada4..c1a5d93 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -1091,11 +1091,11 @@ void kick_process(struct task_struct *p)
{
int cpu;
- preempt_disable();
+ get_online_cpus_stable_atomic();
cpu = task_cpu(p);
if ((cpu != smp_processor_id()) && task_curr(p))
smp_send_reschedule(cpu);
- preempt_enable();
+ put_online_cpus_stable_atomic();
}
EXPORT_SYMBOL_GPL(kick_process);
#endif /* CONFIG_SMP */
next prev parent reply other threads:[~2012-12-04 8:56 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-12-04 8:53 [RFC PATCH 00/10] CPU hotplug: stop_machine()-free CPU hotplug Srivatsa S. Bhat
2012-12-04 8:53 ` [RFC PATCH 01/10] CPU hotplug: Introduce "stable" cpu online mask, for atomic hotplug readers Srivatsa S. Bhat
2012-12-04 15:17 ` Tejun Heo
2012-12-04 21:14 ` Srivatsa S. Bhat
2012-12-04 22:10 ` Andrew Morton
2012-12-05 2:56 ` Michael Wang
2012-12-05 3:28 ` Michael Wang
2012-12-05 12:38 ` Srivatsa S. Bhat
2012-12-04 8:54 ` [RFC PATCH 02/10] smp, cpu hotplug: Fix smp_call_function_*() to prevent CPU offline properly Srivatsa S. Bhat
2012-12-04 22:17 ` Andrew Morton
2012-12-05 12:41 ` Srivatsa S. Bhat
2012-12-04 23:39 ` Rusty Russell
2012-12-05 12:44 ` Srivatsa S. Bhat
2012-12-04 8:54 ` [RFC PATCH 03/10] smp, cpu hotplug: Fix on_each_cpu_*() " Srivatsa S. Bhat
2012-12-04 8:54 ` [RFC PATCH 04/10] sched, cpu hotplug: Use stable online cpus in try_to_wake_up() & select_task_rq() Srivatsa S. Bhat
2012-12-04 8:55 ` Srivatsa S. Bhat [this message]
2012-12-04 8:55 ` [RFC PATCH 06/10] yield_to(), cpu-hotplug: Prevent offlining of other CPUs properly Srivatsa S. Bhat
2012-12-04 8:55 ` [RFC PATCH 07/10] KVM: VMX: fix invalid cpu passed to smp_call_function_single Srivatsa S. Bhat
2012-12-04 8:55 ` [RFC PATCH 08/10] KVM: VMX: fix memory order between loading vmcs and clearing vmcs Srivatsa S. Bhat
2012-12-04 8:56 ` [RFC PATCH 09/10] KVM: VMX: fix unsyc vmcs status when cpu is going down Srivatsa S. Bhat
2012-12-04 8:56 ` [RFC PATCH 10/10] cpu: No more __stop_machine() in _cpu_down() Srivatsa S. Bhat
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