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Commit 981a4cb3 authored by Alexander Shishkin's avatar Alexander Shishkin Committed by Ingo Molnar
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perf/x86/intel/bts: Move transaction start/stop to start/stop callbacks 



As per AUX buffer management requirement, AUX output has to happen between
pmu::start and pmu::stop calls so that perf_event_stop() actually stops it
and therefore perf can free the AUX data after it has called pmu::stop.

This patch moves perf_aux_output_{begin,end} from bts_event_{add,del} to
bts_event_{start,stop}. As a bonus, we get rid of bts_buffer_is_full(),
which is already taken care of by perf_aux_output_begin() anyway.

Signed-off-by: default avatarAlexander Shishkin <alexander.shishkin@linux.intel.com>
Signed-off-by: default avatarPeter Zijlstra (Intel) <peterz@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@infradead.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Vince Weaver <vincent.weaver@maine.edu>
Cc: vince@deater.net
Link: http://lkml.kernel.org/r/1457098969-21595-6-git-send-email-alexander.shishkin@linux.intel.com


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 66d21901

arch/x86/events/intel/bts.c

+48 −57
Original line number Diff line number Diff line
@@ -171,18 +171,6 @@ static void bts_buffer_pad_out(struct bts_phys *phys, unsigned long head) 
	memset(page_address(phys->page) + index, 0, phys->size - index);

}



static bool bts_buffer_is_full(struct bts_buffer *buf, struct bts_ctx *bts)

{

	if (buf->snapshot)

		return false;



	if (local_read(&buf->data_size) >= bts->handle.size ||

	    bts->handle.size - local_read(&buf->data_size) < BTS_RECORD_SIZE)

		return true;



	return false;

}



static void bts_update(struct bts_ctx *bts)

{

	int cpu = raw_smp_processor_id();
@@ -213,18 +201,15 @@ static void bts_update(struct bts_ctx *bts) 
	}

}



static int

bts_buffer_reset(struct bts_buffer *buf, struct perf_output_handle *handle);



static void __bts_event_start(struct perf_event *event)

{

	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);

	struct bts_buffer *buf = perf_get_aux(&bts->handle);

	u64 config = 0;



	if (!buf || bts_buffer_is_full(buf, bts))

		return;



	event->hw.itrace_started = 1;

	event->hw.state = 0;



	if (!buf->snapshot)

		config |= ARCH_PERFMON_EVENTSEL_INT;

	if (!event->attr.exclude_kernel)
@@ -241,16 +226,41 @@ static void __bts_event_start(struct perf_event *event) 
	wmb();



	intel_pmu_enable_bts(config);



}



static void bts_event_start(struct perf_event *event, int flags)

{

	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);

	struct bts_buffer *buf;



	buf = perf_aux_output_begin(&bts->handle, event);

	if (!buf)

		goto fail_stop;



	if (bts_buffer_reset(buf, &bts->handle))

		goto fail_end_stop;



	bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;

	bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum;

	bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold;



	event->hw.itrace_started = 1;

	event->hw.state = 0;



	__bts_event_start(event);



	/* PMI handler: this counter is running and likely generating PMIs */

	ACCESS_ONCE(bts->started) = 1;



	return;



fail_end_stop:

	perf_aux_output_end(&bts->handle, 0, false);



fail_stop:

	event->hw.state = PERF_HES_STOPPED;

}



static void __bts_event_stop(struct perf_event *event)
@@ -269,15 +279,32 @@ static void __bts_event_stop(struct perf_event *event) 


static void bts_event_stop(struct perf_event *event, int flags)

{

	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);

	struct bts_buffer *buf = perf_get_aux(&bts->handle);



	/* PMI handler: don't restart this counter */

	ACCESS_ONCE(bts->started) = 0;



	__bts_event_stop(event);



	if (flags & PERF_EF_UPDATE)

	if (flags & PERF_EF_UPDATE) {

		bts_update(bts);



		if (buf) {

			if (buf->snapshot)

				bts->handle.head =

					local_xchg(&buf->data_size,

						   buf->nr_pages << PAGE_SHIFT);

			perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0),

					    !!local_xchg(&buf->lost, 0));

		}



		cpuc->ds->bts_index = bts->ds_back.bts_buffer_base;

		cpuc->ds->bts_buffer_base = bts->ds_back.bts_buffer_base;

		cpuc->ds->bts_absolute_maximum = bts->ds_back.bts_absolute_maximum;

		cpuc->ds->bts_interrupt_threshold = bts->ds_back.bts_interrupt_threshold;

	}

}



void intel_bts_enable_local(void)
@@ -417,34 +444,14 @@ int intel_bts_interrupt(void) 


static void bts_event_del(struct perf_event *event, int mode)

{

	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);

	struct bts_buffer *buf = perf_get_aux(&bts->handle);



	bts_event_stop(event, PERF_EF_UPDATE);



	if (buf) {

		if (buf->snapshot)

			bts->handle.head =

				local_xchg(&buf->data_size,

					   buf->nr_pages << PAGE_SHIFT);

		perf_aux_output_end(&bts->handle, local_xchg(&buf->data_size, 0),

				    !!local_xchg(&buf->lost, 0));

	}



	cpuc->ds->bts_index = bts->ds_back.bts_buffer_base;

	cpuc->ds->bts_buffer_base = bts->ds_back.bts_buffer_base;

	cpuc->ds->bts_absolute_maximum = bts->ds_back.bts_absolute_maximum;

	cpuc->ds->bts_interrupt_threshold = bts->ds_back.bts_interrupt_threshold;

}



static int bts_event_add(struct perf_event *event, int mode)

{

	struct bts_buffer *buf;

	struct bts_ctx *bts = this_cpu_ptr(&bts_ctx);

	struct cpu_hw_events *cpuc = this_cpu_ptr(&cpu_hw_events);

	struct hw_perf_event *hwc = &event->hw;

	int ret = -EBUSY;



	event->hw.state = PERF_HES_STOPPED;
@@ -454,26 +461,10 @@ static int bts_event_add(struct perf_event *event, int mode) 
	if (bts->handle.event)

		return -EBUSY;



	buf = perf_aux_output_begin(&bts->handle, event);

	if (!buf)

		return -EINVAL;



	ret = bts_buffer_reset(buf, &bts->handle);

	if (ret) {

		perf_aux_output_end(&bts->handle, 0, false);

		return ret;

	}



	bts->ds_back.bts_buffer_base = cpuc->ds->bts_buffer_base;

	bts->ds_back.bts_absolute_maximum = cpuc->ds->bts_absolute_maximum;

	bts->ds_back.bts_interrupt_threshold = cpuc->ds->bts_interrupt_threshold;



	if (mode & PERF_EF_START) {

		bts_event_start(event, 0);

		if (hwc->state & PERF_HES_STOPPED) {

			bts_event_del(event, 0);

			return -EBUSY;

		}

		if (hwc->state & PERF_HES_STOPPED)

			return -EINVAL;

	}



	return 0;