[patch V2 10/24] perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked()

Thomas Gleixner
2017-04-18T19:50:43Z

[-- Attachment #1: perfx86intelcqm_Use_cpuhp_setup_state_locked.patch --]
[-- Type: text/plain, Size: 1423 bytes --]

From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>

intel_cqm_init() holds get_online_cpus() while registerring the hotplug
callbacks.

cpuhp_setup_state() invokes get_online_cpus() as well. This is correct, but
prevents the conversion of the hotplug locking to a percpu rwsem.

Use cpuhp_setup_state_cpuslocked() to avoid the nested call.

Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: x86@kernel.org
Cc: Fenghua Yu <fenghua.yu@intel.com>

---
arch/x86/events/intel/cqm.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

--- a/arch/x86/events/intel/cqm.c
+++ b/arch/x86/events/intel/cqm.c
@@ -1746,12 +1746,12 @@ static int __init intel_cqm_init(void)
* Setup the hot cpu notifier once we are sure cqm
* is enabled to avoid notifier leak.
*/
- cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_STARTING,
- "perf/x86/cqm:starting",
- intel_cqm_cpu_starting, NULL);
- cpuhp_setup_state(CPUHP_AP_PERF_X86_CQM_ONLINE, "perf/x86/cqm:online",
- NULL, intel_cqm_cpu_exit);
-
+ cpuhp_setup_state_cpuslocked(CPUHP_AP_PERF_X86_CQM_STARTING,
+ "perf/x86/cqm:starting",
+ intel_cqm_cpu_starting, NULL);
+ cpuhp_setup_state_cpuslocked(CPUHP_AP_PERF_X86_CQM_ONLINE,
+ "perf/x86/cqm:online",
+ NULL, intel_cqm_cpu_exit);
out:
put_online_cpus();