Merge tag 'v2.6.38' of git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux-2.6

[mv-sheeva.git] / kernel / perf_event.c

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index 126a302c481c060782e811e92e3fca0386271208..656222fcf767e4442acaf291a9bca566f9332d00 100644 (file)
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -782,6 +782,10 @@ retry:
        raw_spin_unlock_irq(&ctx->lock);
 }
 
+#define MAX_INTERRUPTS (~0ULL)
+
+static void perf_log_throttle(struct perf_event *event, int enable);
+
 static int
 event_sched_in(struct perf_event *event,
                 struct perf_cpu_context *cpuctx,
@@ -794,6 +798,17 @@ event_sched_in(struct perf_event *event,
 
        event->state = PERF_EVENT_STATE_ACTIVE;
        event->oncpu = smp_processor_id();
+
+       /*
+        * Unthrottle events, since we scheduled we might have missed several
+        * ticks already, also for a heavily scheduling task there is little
+        * guarantee it'll get a tick in a timely manner.
+        */
+       if (unlikely(event->hw.interrupts == MAX_INTERRUPTS)) {
+               perf_log_throttle(event, 1);
+               event->hw.interrupts = 0;
+       }
+
        /*
         * The new state must be visible before we turn it on in the hardware:
         */
@@ -1596,10 +1611,6 @@ void __perf_event_task_sched_in(struct task_struct *task)
        }
 }
 
-#define MAX_INTERRUPTS (~0ULL)
-
-static void perf_log_throttle(struct perf_event *event, int enable);
-
 static u64 perf_calculate_period(struct perf_event *event, u64 nsec, u64 count)
 {
        u64 frequency = event->attr.sample_freq;
@@ -1901,11 +1912,12 @@ static void __perf_event_read(void *info)
                return;
 
        raw_spin_lock(&ctx->lock);
-       update_context_time(ctx);
+       if (ctx->is_active)
+               update_context_time(ctx);
        update_event_times(event);
+       if (event->state == PERF_EVENT_STATE_ACTIVE)
+               event->pmu->read(event);
        raw_spin_unlock(&ctx->lock);
-
-       event->pmu->read(event);
 }
 
 static inline u64 perf_event_count(struct perf_event *event)
@@ -1999,8 +2011,7 @@ static int alloc_callchain_buffers(void)
         * accessed from NMI. Use a temporary manual per cpu allocation
         * until that gets sorted out.
         */
-       size = sizeof(*entries) + sizeof(struct perf_callchain_entry *) *
-               num_possible_cpus();
+       size = offsetof(struct callchain_cpus_entries, cpu_entries[nr_cpu_ids]);
 
        entries = kzalloc(size, GFP_KERNEL);
        if (!entries)