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Subject[tip:smp/hotplug] perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked()
Commit-ID:  88840592a3483951be52f3ed35f4c4348dc9eed9
Gitweb: http://git.kernel.org/tip/88840592a3483951be52f3ed35f4c4348dc9eed9
Author: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
AuthorDate: Tue, 18 Apr 2017 19:04:52 +0200
Committer: Thomas Gleixner <tglx@linutronix.de>
CommitDate: Thu, 20 Apr 2017 13:08:53 +0200

perf/x86/intel/cqm: Use cpuhp_setup_state_cpuslocked()

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: Fenghua Yu <fenghua.yu@intel.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Link: http://lkml.kernel.org/r/20170418170553.191578891@linutronix.de
---
arch/x86/events/intel/cqm.c | 12 ++++++------
1 file changed, 6 insertions(+), 6 deletions(-)

diff --git a/arch/x86/events/intel/cqm.c b/arch/x86/events/intel/cqm.c
index 8c00dc0..2d4a842 100644
--- 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();

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