From 66d219014a4ee47ad4ca2b9db5fe6547353e2a56 Mon Sep 17 00:00:00 2001 From: Alexander Shishkin Date: Fri, 4 Mar 2016 15:42:48 +0200 Subject: [PATCH] perf/x86/intel/pt: Move transaction start/stop to PMU 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 pt_event_{add,del} to pt_event_{start,stop}. As a bonus, we get rid of pt_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/1457098969-21595-5-git-send-email-alexander.shishkin@linux.intel.com Signed-off-by: Ingo Molnar --- arch/x86/events/intel/pt.c | 85 ++++++++++++-------------------------- 1 file changed, 27 insertions(+), 58 deletions(-) diff --git a/arch/x86/events/intel/pt.c b/arch/x86/events/intel/pt.c index 6af7cf71d6b2..127f58c17976 100644 --- a/arch/x86/events/intel/pt.c +++ b/arch/x86/events/intel/pt.c @@ -905,26 +905,6 @@ static void pt_buffer_free_aux(void *data) kfree(buf); } -/** - * pt_buffer_is_full() - check if the buffer is full - * @buf: PT buffer. - * @pt: Per-cpu pt handle. - * - * If the user hasn't read data from the output region that aux_head - * points to, the buffer is considered full: the user needs to read at - * least this region and update aux_tail to point past it. - */ -static bool pt_buffer_is_full(struct pt_buffer *buf, struct pt *pt) -{ - if (buf->snapshot) - return false; - - if (local_read(&buf->data_size) >= pt->handle.size) - return true; - - return false; -} - /** * intel_pt_interrupt() - PT PMI handler */ @@ -989,20 +969,33 @@ void intel_pt_interrupt(void) static void pt_event_start(struct perf_event *event, int mode) { + struct hw_perf_event *hwc = &event->hw; struct pt *pt = this_cpu_ptr(&pt_ctx); - struct pt_buffer *buf = perf_get_aux(&pt->handle); + struct pt_buffer *buf; - if (!buf || pt_buffer_is_full(buf, pt)) { - event->hw.state = PERF_HES_STOPPED; - return; + buf = perf_aux_output_begin(&pt->handle, event); + if (!buf) + goto fail_stop; + + pt_buffer_reset_offsets(buf, pt->handle.head); + if (!buf->snapshot) { + if (pt_buffer_reset_markers(buf, &pt->handle)) + goto fail_end_stop; } ACCESS_ONCE(pt->handle_nmi) = 1; - event->hw.state = 0; + hwc->state = 0; pt_config_buffer(buf->cur->table, buf->cur_idx, buf->output_off); pt_config(event); + + return; + +fail_end_stop: + perf_aux_output_end(&pt->handle, 0, true); +fail_stop: + hwc->state = PERF_HES_STOPPED; } static void pt_event_stop(struct perf_event *event, int mode) @@ -1035,19 +1028,7 @@ static void pt_event_stop(struct perf_event *event, int mode) pt_handle_status(pt); pt_update_head(pt); - } -} -static void pt_event_del(struct perf_event *event, int mode) -{ - struct pt *pt = this_cpu_ptr(&pt_ctx); - struct pt_buffer *buf; - - pt_event_stop(event, PERF_EF_UPDATE); - - buf = perf_get_aux(&pt->handle); - - if (buf) { if (buf->snapshot) pt->handle.head = local_xchg(&buf->data_size, @@ -1057,9 +1038,13 @@ static void pt_event_del(struct perf_event *event, int mode) } } +static void pt_event_del(struct perf_event *event, int mode) +{ + pt_event_stop(event, PERF_EF_UPDATE); +} + static int pt_event_add(struct perf_event *event, int mode) { - struct pt_buffer *buf; struct pt *pt = this_cpu_ptr(&pt_ctx); struct hw_perf_event *hwc = &event->hw; int ret = -EBUSY; @@ -1067,34 +1052,18 @@ static int pt_event_add(struct perf_event *event, int mode) if (pt->handle.event) goto fail; - buf = perf_aux_output_begin(&pt->handle, event); - ret = -EINVAL; - if (!buf) - goto fail_stop; - - pt_buffer_reset_offsets(buf, pt->handle.head); - if (!buf->snapshot) { - ret = pt_buffer_reset_markers(buf, &pt->handle); - if (ret) - goto fail_end_stop; - } - if (mode & PERF_EF_START) { pt_event_start(event, 0); - ret = -EBUSY; + ret = -EINVAL; if (hwc->state == PERF_HES_STOPPED) - goto fail_end_stop; + goto fail; } else { hwc->state = PERF_HES_STOPPED; } - return 0; - -fail_end_stop: - perf_aux_output_end(&pt->handle, 0, true); -fail_stop: - hwc->state = PERF_HES_STOPPED; + ret = 0; fail: + return ret; } -- 2.30.2