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Commit fe9081cc authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

perf, x86: Add simple group validation 



Refuse to add events when the group wouldn't fit onto the PMU
anymore.

Naive implementation.

Signed-off-by: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@gmail.com>
LKML-Reference: <1254911461.26976.239.camel@twins>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent b690081d

arch/x86/kernel/cpu/perf_event.c

+69 −21
Original line number Diff line number Diff line
@@ -114,7 +114,8 @@ struct x86_pmu { 
	u64		intel_ctrl;

	void		(*enable_bts)(u64 config);

	void		(*disable_bts)(void);

	int		(*get_event_idx)(struct hw_perf_event *hwc);

	int		(*get_event_idx)(struct cpu_hw_events *cpuc,

					 struct hw_perf_event *hwc);

};



static struct x86_pmu x86_pmu __read_mostly;
@@ -1390,8 +1391,7 @@ static void amd_pmu_enable_event(struct hw_perf_event *hwc, int idx) 
		x86_pmu_enable_event(hwc, idx);

}



static int

fixed_mode_idx(struct perf_event *event, struct hw_perf_event *hwc)

static int fixed_mode_idx(struct hw_perf_event *hwc)

{

	unsigned int hw_event;
@@ -1424,9 +1424,9 @@ fixed_mode_idx(struct perf_event *event, struct hw_perf_event *hwc) 
/*

 * generic counter allocator: get next free counter

 */

static int gen_get_event_idx(struct hw_perf_event *hwc)

static int

gen_get_event_idx(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	int idx;



	idx = find_first_zero_bit(cpuc->used_mask, x86_pmu.num_events);
@@ -1436,16 +1436,16 @@ static int gen_get_event_idx(struct hw_perf_event *hwc) 
/*

 * intel-specific counter allocator: check event constraints

 */

static int intel_get_event_idx(struct hw_perf_event *hwc)

static int

intel_get_event_idx(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	const struct event_constraint *event_constraint;

	int i, code;



	if (!event_constraint)

		goto skip;



	code = hwc->config & 0xff;

	code = hwc->config & CORE_EVNTSEL_EVENT_MASK;



	for_each_event_constraint(event_constraint, event_constraint) {

		if (code == event_constraint->code) {
@@ -1457,19 +1457,15 @@ static int intel_get_event_idx(struct hw_perf_event *hwc) 
		}

	}

skip:

	return gen_get_event_idx(hwc);

	return gen_get_event_idx(cpuc, hwc);

}



/*

 * Find a PMC slot for the freshly enabled / scheduled in event:

 */

static int x86_pmu_enable(struct perf_event *event)

static int

x86_schedule_event(struct cpu_hw_events *cpuc, struct hw_perf_event *hwc)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int idx;



	idx = fixed_mode_idx(event, hwc);

	idx = fixed_mode_idx(hwc);

	if (idx == X86_PMC_IDX_FIXED_BTS) {

		/* BTS is already occupied. */

		if (test_and_set_bit(idx, cpuc->used_mask))
@@ -1499,7 +1495,7 @@ static int x86_pmu_enable(struct perf_event *event) 
		/* Try to get the previous generic event again */

		if (idx == -1 || test_and_set_bit(idx, cpuc->used_mask)) {

try_generic:

			idx = x86_pmu.get_event_idx(hwc);

			idx = x86_pmu.get_event_idx(cpuc, hwc);

			if (idx == -1)

				return -EAGAIN;
@@ -1510,6 +1506,22 @@ try_generic: 
		hwc->event_base  = x86_pmu.perfctr;

	}



	return idx;

}



/*

 * Find a PMC slot for the freshly enabled / scheduled in event:

 */

static int x86_pmu_enable(struct perf_event *event)

{

	struct cpu_hw_events *cpuc = &__get_cpu_var(cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int idx;



	idx = x86_schedule_event(cpuc, hwc);

	if (idx < 0)

		return idx;



	perf_events_lapic_init();



	x86_pmu.disable(hwc, idx);
@@ -2212,11 +2224,47 @@ static const struct pmu pmu = { 
	.unthrottle	= x86_pmu_unthrottle,

};



static int

validate_event(struct cpu_hw_events *cpuc, struct perf_event *event)

{

	struct hw_perf_event fake_event = event->hw;



	if (event->pmu != &pmu)

		return 0;



	return x86_schedule_event(cpuc, &fake_event);

}



static int validate_group(struct perf_event *event)

{

	struct perf_event *sibling, *leader = event->group_leader;

	struct cpu_hw_events fake_pmu;



	memset(&fake_pmu, 0, sizeof(fake_pmu));



	if (!validate_event(&fake_pmu, leader))

		return -ENOSPC;



	list_for_each_entry(sibling, &leader->sibling_list, group_entry) {

		if (!validate_event(&fake_pmu, sibling))

			return -ENOSPC;

	}



	if (!validate_event(&fake_pmu, event))

		return -ENOSPC;



	return 0;

}



const struct pmu *hw_perf_event_init(struct perf_event *event)

{

	int err;



	err = __hw_perf_event_init(event);

	if (!err) {

		if (event->group_leader != event)

			err = validate_group(event);

	}

	if (err) {

		if (event->destroy)

			event->destroy(event);