From 981a4cb380d3dff7010ce9f89618064a254eab8c Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 4 Mar 2016 15:42:49 +0200 Subject: [PATCH] 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: Alexander Shishkin Signed-off-by: Peter Zijlstra (Intel) Cc: Arnaldo Carvalho de Melo Cc: Arnaldo Carvalho de Melo Cc: Jiri Olsa Cc: Linus Torvalds Cc: Mathieu Poirier Cc: Peter Zijlstra Cc: Stephane Eranian Cc: Thomas Gleixner Cc: Vince Weaver Cc: vince@deater.net Link: http://lkml.kernel.org/r/1457098969-21595-6-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/events/intel/bts.c | 105 +++++++++++++++++------------------- 1 file changed, 48 insertions(+), 57 deletions(-) diff --git a/arch/x86/events/intel/bts.c b/arch/x86/events/intel/bts.c index b99dc9258c0f..0a6e393a2e62 100644 --- a/arch/x86/events/intel/bts.c +++ b/arch/x86/events/intel/bts.c @@ -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; -- 2.20.1