From 4c9e25428ff46b968a30f1dfafdba550cb6e4141 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Mon, 6 Apr 2009 11:45:09 +0200 Subject: [PATCH] perf_counter: change event definition Currently the definition of an event is slightly ambiguous. We have wakeup events, for poll() and SIGIO, which are either generated when a record crosses a page boundary (hw_events.wakeup_events == 0), or every wakeup_events new records. Now a record can be either a counter overflow record, or a number of different things, like the mmap PROT_EXEC region notifications. Then there is the PERF_COUNTER_IOC_REFRESH event limit, which only considers counter overflows. This patch changes then wakeup_events and SIGIO notification to only consider overflow events. Furthermore it changes the SIGIO notification to report SIGHUP when the event limit is reached and the counter will be disabled. Signed-off-by: Peter Zijlstra Cc: Paul Mackerras Cc: Corey Ashford LKML-Reference: <20090406094518.266679874@chello.nl> Signed-off-by: Ingo Molnar --- include/linux/perf_counter.h | 1 + kernel/perf_counter.c | 22 +++++++++++++++------- 2 files changed, 16 insertions(+), 7 deletions(-) diff --git a/include/linux/perf_counter.h b/include/linux/perf_counter.h index 81220188d058..0f5a4005048f 100644 --- a/include/linux/perf_counter.h +++ b/include/linux/perf_counter.h @@ -439,6 +439,7 @@ struct perf_counter { /* delayed work for NMIs and such */ int pending_wakeup; + int pending_kill; int pending_disable; struct perf_pending_entry pending; diff --git a/kernel/perf_counter.c b/kernel/perf_counter.c index c05e10354bc9..8c8eaf0625f9 100644 --- a/kernel/perf_counter.c +++ b/kernel/perf_counter.c @@ -1596,7 +1596,11 @@ void perf_counter_wakeup(struct perf_counter *counter) rcu_read_unlock(); wake_up_all(&counter->waitq); - kill_fasync(&counter->fasync, SIGIO, POLL_IN); + + if (counter->pending_kill) { + kill_fasync(&counter->fasync, SIGIO, counter->pending_kill); + counter->pending_kill = 0; + } } /* @@ -1727,6 +1731,7 @@ struct perf_output_handle { unsigned int head; int wakeup; int nmi; + int overflow; }; static inline void __perf_output_wakeup(struct perf_output_handle *handle) @@ -1741,7 +1746,7 @@ static inline void __perf_output_wakeup(struct perf_output_handle *handle) static int perf_output_begin(struct perf_output_handle *handle, struct perf_counter *counter, unsigned int size, - int nmi) + int nmi, int overflow) { struct perf_mmap_data *data; unsigned int offset, head; @@ -1751,8 +1756,9 @@ static int perf_output_begin(struct perf_output_handle *handle, if (!data) goto out; - handle->counter = counter; - handle->nmi = nmi; + handle->counter = counter; + handle->nmi = nmi; + handle->overflow = overflow; if (!data->nr_pages) goto fail; @@ -1816,7 +1822,7 @@ static void perf_output_end(struct perf_output_handle *handle) { int wakeup_events = handle->counter->hw_event.wakeup_events; - if (wakeup_events) { + if (handle->overflow && wakeup_events) { int events = atomic_inc_return(&handle->data->events); if (events >= wakeup_events) { atomic_sub(wakeup_events, &handle->data->events); @@ -1891,7 +1897,7 @@ static void perf_counter_output(struct perf_counter *counter, header.size += sizeof(u64); } - ret = perf_output_begin(&handle, counter, header.size, nmi); + ret = perf_output_begin(&handle, counter, header.size, nmi, 1); if (ret) return; @@ -1955,7 +1961,7 @@ static void perf_counter_mmap_output(struct perf_counter *counter, { struct perf_output_handle handle; int size = mmap_event->event.header.size; - int ret = perf_output_begin(&handle, counter, size, 0); + int ret = perf_output_begin(&handle, counter, size, 0, 0); if (ret) return; @@ -2084,8 +2090,10 @@ int perf_counter_overflow(struct perf_counter *counter, int events = atomic_read(&counter->event_limit); int ret = 0; + counter->pending_kill = POLL_IN; if (events && atomic_dec_and_test(&counter->event_limit)) { ret = 1; + counter->pending_kill = POLL_HUP; if (nmi) { counter->pending_disable = 1; perf_pending_queue(&counter->pending, -- 2.34.1