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,