diff options
Diffstat (limited to 'patches/0017-cpu-hotplug-Use-stop_machine_cpuslocked-in-takedown_.patch')
| -rw-r--r-- | patches/0017-cpu-hotplug-Use-stop_machine_cpuslocked-in-takedown_.patch | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/patches/0017-cpu-hotplug-Use-stop_machine_cpuslocked-in-takedown_.patch b/patches/0017-cpu-hotplug-Use-stop_machine_cpuslocked-in-takedown_.patch new file mode 100644 index 000000000000..80b204a20340 --- /dev/null +++ b/patches/0017-cpu-hotplug-Use-stop_machine_cpuslocked-in-takedown_.patch @@ -0,0 +1,41 @@ +From 210e21331fc3a396af640cec652be769d146e49f Mon Sep 17 00:00:00 2001 +From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +Date: Wed, 24 May 2017 10:15:28 +0200 +Subject: [PATCH 17/32] 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 e4389ac55b65..142d889d9f69 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(); +-- +2.11.0 + |