From 4f1ced166823def67006912ec3e89f0f3f565432 Mon Sep 17 00:00:00 2001
From: Peter Zijlstra <a.p.zijlstra@chello.nl>
Date: Wed, 16 Nov 2011 14:38:16 +0100
Subject: [PATCH] --- yaml --- r: 277313 b: refs/heads/master c:
 0f5a2601284237e2ba089389fd75d67f77626cef h: refs/heads/master i:   277311:
 1d5ae954245d295868327c3c2e54a214b221ef77 v: v3

---
 [refs]                           |  2 +-
 trunk/include/linux/perf_event.h |  1 +
 trunk/kernel/events/core.c       | 48 +++++++++++++++++++++-----------
 3 files changed, 34 insertions(+), 17 deletions(-)

diff --git a/[refs] b/[refs]
index cd120c22f155..7c9341a2dc07 100644
--- a/[refs]
+++ b/[refs]
@@ -1,2 +1,2 @@
 ---
-refs/heads/master: d6c1c49de577fa292af2449817364b7d89b574d8
+refs/heads/master: 0f5a2601284237e2ba089389fd75d67f77626cef
diff --git a/trunk/include/linux/perf_event.h b/trunk/include/linux/perf_event.h
index b1f89122bf6a..cb44c9e75660 100644
--- a/trunk/include/linux/perf_event.h
+++ b/trunk/include/linux/perf_event.h
@@ -890,6 +890,7 @@ struct perf_event_context {
 	int				nr_active;
 	int				is_active;
 	int				nr_stat;
+	int				nr_freq;
 	int				rotate_disable;
 	atomic_t			refcount;
 	struct task_struct		*task;
diff --git a/trunk/kernel/events/core.c b/trunk/kernel/events/core.c
index a355ffb0b28f..b3fed52aaf20 100644
--- a/trunk/kernel/events/core.c
+++ b/trunk/kernel/events/core.c
@@ -1130,6 +1130,8 @@ event_sched_out(struct perf_event *event,
 	if (!is_software_event(event))
 		cpuctx->active_oncpu--;
 	ctx->nr_active--;
+	if (event->attr.freq && event->attr.sample_freq)
+		ctx->nr_freq--;
 	if (event->attr.exclusive || !cpuctx->active_oncpu)
 		cpuctx->exclusive = 0;
 }
@@ -1407,6 +1409,8 @@ event_sched_in(struct perf_event *event,
 	if (!is_software_event(event))
 		cpuctx->active_oncpu++;
 	ctx->nr_active++;
+	if (event->attr.freq && event->attr.sample_freq)
+		ctx->nr_freq++;
 
 	if (event->attr.exclusive)
 		cpuctx->exclusive = 1;
@@ -2329,6 +2333,9 @@ static void perf_ctx_adjust_freq(struct perf_event_context *ctx, u64 period)
 	u64 interrupts, now;
 	s64 delta;
 
+	if (!ctx->nr_freq)
+		return;
+
 	list_for_each_entry_rcu(event, &ctx->event_list, event_entry) {
 		if (event->state != PERF_EVENT_STATE_ACTIVE)
 			continue;
@@ -2384,12 +2391,14 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 {
 	u64 interval = (u64)cpuctx->jiffies_interval * TICK_NSEC;
 	struct perf_event_context *ctx = NULL;
-	int rotate = 0, remove = 1;
+	int rotate = 0, remove = 1, freq = 0;
 
 	if (cpuctx->ctx.nr_events) {
 		remove = 0;
 		if (cpuctx->ctx.nr_events != cpuctx->ctx.nr_active)
 			rotate = 1;
+		if (cpuctx->ctx.nr_freq)
+			freq = 1;
 	}
 
 	ctx = cpuctx->task_ctx;
@@ -2397,33 +2406,40 @@ static void perf_rotate_context(struct perf_cpu_context *cpuctx)
 		remove = 0;
 		if (ctx->nr_events != ctx->nr_active)
 			rotate = 1;
+		if (ctx->nr_freq)
+			freq = 1;
 	}
 
+	if (!rotate && !freq)
+		goto done;
+
 	perf_ctx_lock(cpuctx, cpuctx->task_ctx);
 	perf_pmu_disable(cpuctx->ctx.pmu);
-	perf_ctx_adjust_freq(&cpuctx->ctx, interval);
-	if (ctx)
-		perf_ctx_adjust_freq(ctx, interval);
 
-	if (!rotate)
-		goto done;
+	if (freq) {
+		perf_ctx_adjust_freq(&cpuctx->ctx, interval);
+		if (ctx)
+			perf_ctx_adjust_freq(ctx, interval);
+	}
 
-	cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
-	if (ctx)
-		ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
+	if (rotate) {
+		cpu_ctx_sched_out(cpuctx, EVENT_FLEXIBLE);
+		if (ctx)
+			ctx_sched_out(ctx, cpuctx, EVENT_FLEXIBLE);
 
-	rotate_ctx(&cpuctx->ctx);
-	if (ctx)
-		rotate_ctx(ctx);
+		rotate_ctx(&cpuctx->ctx);
+		if (ctx)
+			rotate_ctx(ctx);
+
+		perf_event_sched_in(cpuctx, ctx, current);
+	}
 
-	perf_event_sched_in(cpuctx, ctx, current);
+	perf_pmu_enable(cpuctx->ctx.pmu);
+	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 
 done:
 	if (remove)
 		list_del_init(&cpuctx->rotation_list);
-
-	perf_pmu_enable(cpuctx->ctx.pmu);
-	perf_ctx_unlock(cpuctx, cpuctx->task_ctx);
 }
 
 void perf_event_task_tick(void)