Merge branch 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

* 'perf-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  perf tools: Remove -Wcast-align
  perf tools: Fix compatibility with libelf 0.8 and autodetect
  perf events: Don't generate events for the idle task when exclude_idle is set
  perf events: Fix swevent hrtimer sampling by keeping track of remaining time when enabling/disabling swevent hrtimers

1 files changed, 44 insertions, 22 deletions

diff --git a/kernel/perf_event.c b/kernel/perf_event.c
index afb7ef3dbc44..7f29643c8985 100644
--- a/kernel/perf_event.c
+++ b/kernel/perf_event.c
@@ -3959,8 +3959,9 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
                 regs = task_pt_regs(current);
 
         if (regs) {
-                if (perf_event_overflow(event, 0, &data, regs))
-                        ret = HRTIMER_NORESTART;
+                if (!(event->attr.exclude_idle && current->pid == 0))
+                        if (perf_event_overflow(event, 0, &data, regs))
+                                ret = HRTIMER_NORESTART;
         }
 
         period = max_t(u64, 10000, event->hw.sample_period);
@@ -3969,6 +3970,42 @@ static enum hrtimer_restart perf_swevent_hrtimer(struct hrtimer *hrtimer)
         return ret;
 }
 
+static void perf_swevent_start_hrtimer(struct perf_event *event)
+{
+        struct hw_perf_event *hwc = &event->hw;
+
+        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
+        hwc->hrtimer.function = perf_swevent_hrtimer;
+        if (hwc->sample_period) {
+                u64 period;
+
+                if (hwc->remaining) {
+                        if (hwc->remaining < 0)
+                                period = 10000;
+                        else
+                                period = hwc->remaining;
+                        hwc->remaining = 0;
+                } else {
+                        period = max_t(u64, 10000, hwc->sample_period);
+                }
+                __hrtimer_start_range_ns(&hwc->hrtimer,
+                                ns_to_ktime(period), 0,
+                                HRTIMER_MODE_REL, 0);
+        }
+}
+
+static void perf_swevent_cancel_hrtimer(struct perf_event *event)
+{
+        struct hw_perf_event *hwc = &event->hw;
+
+        if (hwc->sample_period) {
+                ktime_t remaining = hrtimer_get_remaining(&hwc->hrtimer);
+                hwc->remaining = ktime_to_ns(remaining);
+
+                hrtimer_cancel(&hwc->hrtimer);
+        }
+}
+
 /*
  * Software event: cpu wall time clock
  */
@@ -3991,22 +4028,14 @@ static int cpu_clock_perf_event_enable(struct perf_event *event)
         int cpu = raw_smp_processor_id();
 
         atomic64_set(&hwc->prev_count, cpu_clock(cpu));
-        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-        hwc->hrtimer.function = perf_swevent_hrtimer;
-        if (hwc->sample_period) {
-                u64 period = max_t(u64, 10000, hwc->sample_period);
-                __hrtimer_start_range_ns(&hwc->hrtimer,
-                                ns_to_ktime(period), 0,
-                                HRTIMER_MODE_REL, 0);
-        }
+        perf_swevent_start_hrtimer(event);
 
         return 0;
 }
 
 static void cpu_clock_perf_event_disable(struct perf_event *event)
 {
-        if (event->hw.sample_period)
-                hrtimer_cancel(&event->hw.hrtimer);
+        perf_swevent_cancel_hrtimer(event);
         cpu_clock_perf_event_update(event);
 }
 
@@ -4043,22 +4072,15 @@ static int task_clock_perf_event_enable(struct perf_event *event)
         now = event->ctx->time;
 
         atomic64_set(&hwc->prev_count, now);
-        hrtimer_init(&hwc->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_REL);
-        hwc->hrtimer.function = perf_swevent_hrtimer;
-        if (hwc->sample_period) {
-                u64 period = max_t(u64, 10000, hwc->sample_period);
-                __hrtimer_start_range_ns(&hwc->hrtimer,
-                                ns_to_ktime(period), 0,
-                                HRTIMER_MODE_REL, 0);
-        }
+
+        perf_swevent_start_hrtimer(event);
 
         return 0;
 }
 
 static void task_clock_perf_event_disable(struct perf_event *event)
 {
-        if (event->hw.sample_period)
-                hrtimer_cancel(&event->hw.hrtimer);
+        perf_swevent_cancel_hrtimer(event);
         task_clock_perf_event_update(event, event->ctx->time);
 
 }