| Date | Fri, 26 May 2017 01:40:35 -0700 | From | tip-bot for Sebastian Andrzej Siewior <> | Subject | [tip:smp/hotplug] cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu() |
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Commit-ID: 210e21331fc3a396af640cec652be769d146e49f Gitweb: http://git.kernel.org/tip/210e21331fc3a396af640cec652be769d146e49f Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de> AuthorDate: Wed, 24 May 2017 10:15:28 +0200 Committer: Thomas Gleixner <tglx@linutronix.de> CommitDate: Fri, 26 May 2017 10:10:42 +0200
cpu/hotplug: Use stop_machine_cpuslocked() in takedown_cpu()
takedown_cpu() is a cpu hotplug function invoking stop_machine(). The cpu hotplug machinery holds the hotplug lock for write.
stop_machine() invokes get_online_cpus() as well. This is correct, but prevents the conversion of the hotplug locking to a percpu rwsem.
Use stop_machine_cpuslocked() to avoid the nested call.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Thomas Gleixner <tglx@linutronix.de> Tested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Ingo Molnar <mingo@kernel.org> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Steven Rostedt <rostedt@goodmis.org> Link: http://lkml.kernel.org/r/20170524081548.423292433@linutronix.de
--- kernel/cpu.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/kernel/cpu.c b/kernel/cpu.c index e4389ac..142d889 100644 --- a/kernel/cpu.c +++ b/kernel/cpu.c @@ -701,7 +701,7 @@ static int takedown_cpu(unsigned int cpu) /* * So now all preempt/rcu users must observe !cpu_active(). */ - err = stop_machine(take_cpu_down, NULL, cpumask_of(cpu)); + err = stop_machine_cpuslocked(take_cpu_down, NULL, cpumask_of(cpu)); if (err) { /* CPU refused to die */ irq_unlock_sparse();
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