---

yaml
---
r: 147199
b: refs/heads/master
c: d859e29
h: refs/heads/master
i:
  147197: 5707061
  147195: 1e71299
  147191: a2f9167
  147183: c1d81c3
  147167: 7ddc48a
  147135: 6320a8d
  147071: 47ad9ae
  146943: 5d9e81e
v: v3

[refs]

@@ -1,2 +1,2 @@
 ---
-refs/heads/master: 3b6f9e5cb21964b7ce12bf81076f830885563ec8
+refs/heads/master: d859e29fe34cb833071b20aef860ee94fbad9bb2

trunk/include/linux/perf_counter.h

@@ -14,6 +14,7 @@
 #define _LINUX_PERF_COUNTER_H
 
 #include <asm/atomic.h>
+#include <asm/ioctl.h>
 
 #ifdef CONFIG_PERF_COUNTERS
 # include <asm/perf_counter.h>
@@ -94,6 +95,12 @@ struct perf_counter_hw_event {
 	u64			__reserved_2;
 };
 
+/*
+ * Ioctls that can be done on a perf counter fd:
+ */
+#define PERF_COUNTER_IOC_ENABLE		_IO('$', 0)
+#define PERF_COUNTER_IOC_DISABLE	_IO('$', 1)
+
 /*
  * Kernel-internal data types:
  */
@@ -173,8 +180,10 @@ struct perf_counter {
 	struct file			*filp;
 
 	struct perf_counter		*parent;
+	struct list_head		child_list;
+
 	/*
-	 * Protect attach/detach:
+	 * Protect attach/detach and child_list:
 	 */
 	struct mutex			mutex;
 
@@ -199,13 +208,21 @@ struct perf_counter {
 struct perf_counter_context {
 #ifdef CONFIG_PERF_COUNTERS
 	/*
-	 * Protect the list of counters:
+	 * Protect the states of the counters in the list,
+	 * nr_active, and the list:
 	 */
 	spinlock_t		lock;
+	/*
+	 * Protect the list of counters.  Locking either mutex or lock
+	 * is sufficient to ensure the list doesn't change; to change
+	 * the list you need to lock both the mutex and the spinlock.
+	 */
+	struct mutex		mutex;
 
 	struct list_head	counter_list;
 	int			nr_counters;
 	int			nr_active;
+	int			is_active;
 	struct task_struct	*task;
 #endif
 };