| From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Date: Wed, 24 May 2017 10:15:24 +0200 |
| Subject: [PATCH 13/32] 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. Convert |
| *_online_cpus() to the new interfaces while at it. |
| |
| Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| Acked-by: Ingo Molnar <mingo@kernel.org> |
| Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
| Cc: Fenghua Yu <fenghua.yu@intel.com> |
| Cc: Peter Zijlstra <peterz@infradead.org> |
| Cc: Steven Rostedt <rostedt@goodmis.org> |
| Link: http://lkml.kernel.org/r/20170524081548.075604046@linutronix.de |
| --- |
| arch/x86/events/intel/cqm.c | 16 ++++++++-------- |
| 1 file changed, 8 insertions(+), 8 deletions(-) |
| |
| --- a/arch/x86/events/intel/cqm.c |
| +++ b/arch/x86/events/intel/cqm.c |
| @@ -1682,7 +1682,7 @@ static int __init intel_cqm_init(void) |
| * |
| * Also, check that the scales match on all cpus. |
| */ |
| - get_online_cpus(); |
| + cpus_read_lock(); |
| for_each_online_cpu(cpu) { |
| struct cpuinfo_x86 *c = &cpu_data(cpu); |
| |
| @@ -1746,14 +1746,14 @@ 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(); |
| + cpus_read_unlock(); |
| |
| if (ret) { |
| kfree(str); |