1 files changed, 78 insertions, 0 deletions

diff --git a/drivers/oprofile/oprof.c b/drivers/oprofile/oprof.c
index 3cffce90f82a..7bc64af7cf99 100644
--- a/drivers/oprofile/oprof.c
+++ b/drivers/oprofile/oprof.c
@@ -12,6 +12,8 @@
 #include <linux/init.h>
 #include <linux/oprofile.h>
 #include <linux/moduleparam.h>
+#include <linux/workqueue.h>
+#include <linux/time.h>
 #include <asm/mutex.h>
 
 #include "oprof.h"
@@ -27,6 +29,15 @@ unsigned long oprofile_backtrace_depth;
 static unsigned long is_setup;
 static DEFINE_MUTEX(start_mutex);
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static void switch_worker(struct work_struct *work);
+static DECLARE_DELAYED_WORK(switch_work, switch_worker);
+unsigned long timeout_jiffies;
+#define MULTIPLEXING_TIMER_DEFAULT 1
+
+#endif
+
 /* timer
    0 - use performance monitoring hardware if available
    1 - use the timer int mechanism regardless
@@ -87,6 +98,20 @@ out:
         return err;
 }
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static void start_switch_worker(void)
+{
+        schedule_delayed_work(&switch_work, timeout_jiffies);
+}
+
+static void switch_worker(struct work_struct *work)
+{
+        if (!oprofile_ops.switch_events())
+                start_switch_worker();
+}
+
+#endif
 
 /* Actually start profiling (echo 1>/dev/oprofile/enable) */
 int oprofile_start(void)
@@ -108,6 +133,11 @@ int oprofile_start(void)
         if ((err = oprofile_ops.start()))
                 goto out;
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        if (oprofile_ops.switch_events)
+                start_switch_worker();
+#endif
+
         oprofile_started = 1;
 out:
         mutex_unlock(&start_mutex);
@@ -123,6 +153,11 @@ void oprofile_stop(void)
                 goto out;
         oprofile_ops.stop();
         oprofile_started = 0;
+
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        cancel_delayed_work_sync(&switch_work);
+#endif
+
         /* wake up the daemon to read what remains */
         wake_up_buffer_waiter();
 out:
@@ -155,6 +190,36 @@ post_sync:
         mutex_unlock(&start_mutex);
 }
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+/* User inputs in ms, converts to jiffies */
+int oprofile_set_timeout(unsigned long val_msec)
+{
+        int err = 0;
+
+        mutex_lock(&start_mutex);
+
+        if (oprofile_started) {
+                err = -EBUSY;
+                goto out;
+        }
+
+        if (!oprofile_ops.switch_events) {
+                err = -EINVAL;
+                goto out;
+        }
+
+        timeout_jiffies = msecs_to_jiffies(val_msec);
+        if (timeout_jiffies == MAX_JIFFY_OFFSET)
+                timeout_jiffies = msecs_to_jiffies(MULTIPLEXING_TIMER_DEFAULT);
+
+out:
+        mutex_unlock(&start_mutex);
+        return err;
+
+}
+
+#endif
 
 int oprofile_set_backtrace(unsigned long val)
 {
@@ -179,10 +244,23 @@ out:
         return err;
 }
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+
+static void __init oprofile_multiplexing_init(void)
+{
+        timeout_jiffies = msecs_to_jiffies(MULTIPLEXING_TIMER_DEFAULT);
+}
+
+#endif
+
 static int __init oprofile_init(void)
 {
         int err;
 
+#ifdef CONFIG_OPROFILE_EVENT_MULTIPLEX
+        oprofile_multiplexing_init();
+#endif
+
         err = oprofile_arch_init(&oprofile_ops);
 
         if (err < 0 || timer) {