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Commit b38b24ea authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
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perf, x86: Fix AMD hotplug & constraint initialization 



Commit 3f6da390 ("perf: Rework and fix the arch CPU-hotplug hooks") moved
the amd northbridge allocation from CPUS_ONLINE to CPUS_PREPARE_UP
however amd_nb_id() doesn't work yet on prepare so it would simply bail
basically reverting to a state where we do not properly track node wide
constraints - causing weird perf results.

Fix up the AMD NorthBridge initialization code by allocating from
CPU_UP_PREPARE and installing it from CPU_STARTING once we have the
proper nb_id. It also properly deals with the allocation failing.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
[ robustify using amd_has_nb() ]
Signed-off-by: default avatarStephane Eranian <eranian@google.com>
LKML-Reference: <1269353485.5109.48.camel@twins>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 85257024

arch/x86/kernel/cpu/perf_event.c

+5 −3
Original line number Original line Diff line number Diff line
@@ -158,7 +158,7 @@ struct x86_pmu { 
						 struct perf_event *event);

						 struct perf_event *event);

	struct event_constraint *event_constraints;

	struct event_constraint *event_constraints;





	void		(*cpu_prepare)(int cpu);

	int		(*cpu_prepare)(int cpu);

	void		(*cpu_starting)(int cpu);

	void		(*cpu_starting)(int cpu);

	void		(*cpu_dying)(int cpu);

	void		(*cpu_dying)(int cpu);

	void		(*cpu_dead)(int cpu);

	void		(*cpu_dead)(int cpu);
@@ -1333,11 +1333,12 @@ static int __cpuinit 
x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)

x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu)

{

{

	unsigned int cpu = (long)hcpu;

	unsigned int cpu = (long)hcpu;

	int ret = NOTIFY_OK;





	switch (action & ~CPU_TASKS_FROZEN) {

	switch (action & ~CPU_TASKS_FROZEN) {

	case CPU_UP_PREPARE:

	case CPU_UP_PREPARE:

		if (x86_pmu.cpu_prepare)

		if (x86_pmu.cpu_prepare)

			x86_pmu.cpu_prepare(cpu);

			ret = x86_pmu.cpu_prepare(cpu);

		break;

		break;





	case CPU_STARTING:

	case CPU_STARTING:
@@ -1350,6 +1351,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) 
			x86_pmu.cpu_dying(cpu);

			x86_pmu.cpu_dying(cpu);

		break;

		break;





	case CPU_UP_CANCELED:

	case CPU_DEAD:

	case CPU_DEAD:

		if (x86_pmu.cpu_dead)

		if (x86_pmu.cpu_dead)

			x86_pmu.cpu_dead(cpu);

			x86_pmu.cpu_dead(cpu);
@@ -1359,7 +1361,7 @@ x86_pmu_notifier(struct notifier_block *self, unsigned long action, void *hcpu) 
		break;

		break;

	}

	}





	return NOTIFY_OK;

	return ret;

}

}





static void __init pmu_check_apic(void)

static void __init pmu_check_apic(void)

arch/x86/kernel/cpu/perf_event_amd.c

+47 −33
Original line number Original line Diff line number Diff line
@@ -137,6 +137,13 @@ static inline int amd_is_nb_event(struct hw_perf_event *hwc) 
	return (hwc->config & 0xe0) == 0xe0;

	return (hwc->config & 0xe0) == 0xe0;

}

}





static inline int amd_has_nb(struct cpu_hw_events *cpuc)

{

	struct amd_nb *nb = cpuc->amd_nb;



	return nb && nb->nb_id != -1;

}



static void amd_put_event_constraints(struct cpu_hw_events *cpuc,

static void amd_put_event_constraints(struct cpu_hw_events *cpuc,

				      struct perf_event *event)

				      struct perf_event *event)

{

{
@@ -147,7 +154,7 @@ static void amd_put_event_constraints(struct cpu_hw_events *cpuc, 
	/*

	/*

	 * only care about NB events

	 * only care about NB events

	 */

	 */

	if (!(nb && amd_is_nb_event(hwc)))

	if (!(amd_has_nb(cpuc) && amd_is_nb_event(hwc)))

		return;

		return;





	/*

	/*
@@ -214,7 +221,7 @@ amd_get_event_constraints(struct cpu_hw_events *cpuc, struct perf_event *event) 
	/*

	/*

	 * if not NB event or no NB, then no constraints

	 * if not NB event or no NB, then no constraints

	 */

	 */

	if (!(nb && amd_is_nb_event(hwc)))

	if (!(amd_has_nb(cpuc) && amd_is_nb_event(hwc)))

		return &unconstrained;

		return &unconstrained;





	/*

	/*
@@ -293,51 +300,55 @@ static struct amd_nb *amd_alloc_nb(int cpu, int nb_id) 
	return nb;

	return nb;

}

}





static void amd_pmu_cpu_online(int cpu)

static int amd_pmu_cpu_prepare(int cpu)

{

	struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);



	WARN_ON_ONCE(cpuc->amd_nb);



	if (boot_cpu_data.x86_max_cores < 2)

		return NOTIFY_OK;



	cpuc->amd_nb = amd_alloc_nb(cpu, -1);

	if (!cpuc->amd_nb)

		return NOTIFY_BAD;



	return NOTIFY_OK;

}



static void amd_pmu_cpu_starting(int cpu)

{

{

	struct cpu_hw_events *cpu1, *cpu2;

	struct cpu_hw_events *cpuc = &per_cpu(cpu_hw_events, cpu);

	struct amd_nb *nb = NULL;

	struct amd_nb *nb;

	int i, nb_id;

	int i, nb_id;





	if (boot_cpu_data.x86_max_cores < 2)

	if (boot_cpu_data.x86_max_cores < 2)

		return;

		return;





	/*

	 * function may be called too early in the

	 * boot process, in which case nb_id is bogus

	 */

	nb_id = amd_get_nb_id(cpu);

	nb_id = amd_get_nb_id(cpu);

	if (nb_id == BAD_APICID)

	WARN_ON_ONCE(nb_id == BAD_APICID);

		return;



	cpu1 = &per_cpu(cpu_hw_events, cpu);

	cpu1->amd_nb = NULL;





	raw_spin_lock(&amd_nb_lock);

	raw_spin_lock(&amd_nb_lock);





	for_each_online_cpu(i) {

	for_each_online_cpu(i) {

		cpu2 = &per_cpu(cpu_hw_events, i);

		nb = per_cpu(cpu_hw_events, i).amd_nb;

		nb = cpu2->amd_nb;

		if (WARN_ON_ONCE(!nb))

		if (!nb)

			continue;

			continue;

		if (nb->nb_id == nb_id)

			goto found;

	}





	nb = amd_alloc_nb(cpu, nb_id);

		if (nb->nb_id == nb_id) {

	if (!nb) {

			kfree(cpuc->amd_nb);

		pr_err("perf_events: failed NB allocation for CPU%d\n", cpu);

			cpuc->amd_nb = nb;

		raw_spin_unlock(&amd_nb_lock);

			break;

		return;

		}

		}

found:

	}

	nb->refcnt++;



	cpu1->amd_nb = nb;

	cpuc->amd_nb->nb_id = nb_id;

	cpuc->amd_nb->refcnt++;





	raw_spin_unlock(&amd_nb_lock);

	raw_spin_unlock(&amd_nb_lock);

}

}





static void amd_pmu_cpu_offline(int cpu)

static void amd_pmu_cpu_dead(int cpu)

{

{

	struct cpu_hw_events *cpuhw;

	struct cpu_hw_events *cpuhw;
@@ -349,8 +360,10 @@ static void amd_pmu_cpu_offline(int cpu) 
	raw_spin_lock(&amd_nb_lock);

	raw_spin_lock(&amd_nb_lock);





	if (cpuhw->amd_nb) {

	if (cpuhw->amd_nb) {

		if (--cpuhw->amd_nb->refcnt == 0)

		struct amd_nb *nb = cpuhw->amd_nb;

			kfree(cpuhw->amd_nb);



		if (nb->nb_id == -1 || --nb->refcnt == 0)

			kfree(nb);





		cpuhw->amd_nb = NULL;

		cpuhw->amd_nb = NULL;

	}

	}
@@ -379,8 +392,9 @@ static __initconst struct x86_pmu amd_pmu = { 
	.get_event_constraints	= amd_get_event_constraints,

	.get_event_constraints	= amd_get_event_constraints,

	.put_event_constraints	= amd_put_event_constraints,

	.put_event_constraints	= amd_put_event_constraints,





	.cpu_prepare		= amd_pmu_cpu_online,

	.cpu_prepare		= amd_pmu_cpu_prepare,

	.cpu_dead		= amd_pmu_cpu_offline,

	.cpu_starting		= amd_pmu_cpu_starting,

	.cpu_dead		= amd_pmu_cpu_dead,

};

};





static __init int amd_pmu_init(void)

static __init int amd_pmu_init(void)