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Subject: hotplug: Use migrate disable on unplug
From: Thomas Gleixner <tglx@linutronix.de>
Date: Sun, 17 Jul 2011 19:35:29 +0200
Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.9/older/patches-4.9.20-rt16.tar.xz
Migration needs to be disabled accross the unplug handling to make
sure that the unplug thread is off the unplugged cpu.
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
---
kernel/cpu.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
--- a/kernel/cpu.c
+++ b/kernel/cpu.c
@@ -988,14 +988,13 @@ static int __ref _cpu_down(unsigned int
cpumask_andnot(cpumask, cpu_online_mask, cpumask_of(cpu));
set_cpus_allowed_ptr(current, cpumask);
free_cpumask_var(cpumask);
- preempt_disable();
+ migrate_disable();
mycpu = smp_processor_id();
if (mycpu == cpu) {
printk(KERN_ERR "Yuck! Still on unplug CPU\n!");
- preempt_enable();
+ migrate_enable();
return -EBUSY;
}
- preempt_enable();
cpu_hotplug_begin();
ret = cpu_unplug_begin(cpu);
@@ -1044,6 +1043,7 @@ static int __ref _cpu_down(unsigned int
cpu_unplug_done(cpu);
out_cancel:
cpu_hotplug_done();
+ migrate_enable();
/* This post dead nonsense must die */
if (!ret && hasdied)
cpu_notify_nofail(CPU_POST_DEAD, cpu);
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