Donate to e Foundation | Murena handsets with /e/OS | Own a part of Murena! Learn more

Commit 22cc4ccf authored by Yan, Zheng's avatar Yan, Zheng Committed by Ingo Molnar
Browse files

perf/x86: Avoid kfree() in CPU_{STARTING,DYING} 



On -rt kfree() can schedule, but CPU_{STARTING,DYING} should be
atomic. So use a list to defer kfree until CPU_{ONLINE,DEAD}.

Signed-off-by: default avatarYan, Zheng <zheng.z.yan@intel.com>
Acked-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: peterz@infradead.org
Cc: eranian@google.com
Cc: ak@linux.intel.com
Link: http://lkml.kernel.org/r/1366113067-3262-2-git-send-email-zheng.z.yan@intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 73e21ce2

arch/x86/kernel/cpu/perf_event_intel_uncore.c

+25 −3
Original line number Original line Diff line number Diff line
@@ -2622,6 +2622,21 @@ static void __init uncore_pci_exit(void) 
	}

	}

}

}





/* CPU hot plug/unplug are serialized by cpu_add_remove_lock mutex */

static LIST_HEAD(boxes_to_free);



static void __cpuinit uncore_kfree_boxes(void)

{

	struct intel_uncore_box *box;



	while (!list_empty(&boxes_to_free)) {

		box = list_entry(boxes_to_free.next,

				 struct intel_uncore_box, list);

		list_del(&box->list);

		kfree(box);

	}

}



static void __cpuinit uncore_cpu_dying(int cpu)

static void __cpuinit uncore_cpu_dying(int cpu)

{

{

	struct intel_uncore_type *type;

	struct intel_uncore_type *type;
@@ -2636,7 +2651,7 @@ static void __cpuinit uncore_cpu_dying(int cpu) 
			box = *per_cpu_ptr(pmu->box, cpu);

			box = *per_cpu_ptr(pmu->box, cpu);

			*per_cpu_ptr(pmu->box, cpu) = NULL;

			*per_cpu_ptr(pmu->box, cpu) = NULL;

			if (box && atomic_dec_and_test(&box->refcnt))

			if (box && atomic_dec_and_test(&box->refcnt))

				kfree(box);

				list_add(&box->list, &boxes_to_free);

		}

		}

	}

	}

}

}
@@ -2666,8 +2681,11 @@ static int __cpuinit uncore_cpu_starting(int cpu) 
				if (exist && exist->phys_id == phys_id) {

				if (exist && exist->phys_id == phys_id) {

					atomic_inc(&exist->refcnt);

					atomic_inc(&exist->refcnt);

					*per_cpu_ptr(pmu->box, cpu) = exist;

					*per_cpu_ptr(pmu->box, cpu) = exist;

					kfree(box);

					if (box) {

						list_add(&box->list,

							 &boxes_to_free);

						box = NULL;

						box = NULL;

					}

					break;

					break;

				}

				}

			}

			}
@@ -2806,6 +2824,10 @@ static int 
	case CPU_DYING:

	case CPU_DYING:

		uncore_cpu_dying(cpu);

		uncore_cpu_dying(cpu);

		break;

		break;

	case CPU_ONLINE:

	case CPU_DEAD:

		uncore_kfree_boxes();

		break;

	default:

	default:

		break;

		break;

	}

	}