sched: Add a comment to get_cpu_idle_time_us()

The exported function get_cpu_idle_time_us() has no comment describing it; add a kerneldoc comment Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082208.7cb721f0@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: Add a comment to get_cpu_idle_time_us()
The exported function get_cpu_idle_time_us() has no comment describing it; add a kerneldoc comment Signed-off-by: Arjan van de Ven <arjan@linux.intel.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Reviewed-by: Rik van Riel <riel@redhat.com> Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: davej@redhat.com LKML-Reference: <20100509082208.7cb721f0@infradead.org> Signed-off-by: Ingo Molnar <mingo@elte.hu>
Arjan van de Ven · Ingo Molnar
1 parent e7858f52a5
Showing 1 changed file with 14 additions and 0 deletions Side-by-side Diff
kernel/time/tick-sched.c
@@ -179,6 +179,20 @@
 	return now;
 }
  
+/**
+ * get_cpu_idle_time_us - get the total idle time of a cpu
+ * @cpu: CPU number to query
+ * @last_update_time: variable to store update time in
+ *
+ * Return the cummulative idle time (since boot) for a given
+ * CPU, in microseconds. The idle time returned includes
+ * the iowait time (unlike what "top" and co report).
+ *
+ * This time is measured via accounting rather than sampling,
+ * and is as accurate as ktime_get() is.
+ *
+ * This function returns -1 if NOHZ is not enabled.
+ */
 u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
 {
 	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);
...	...	@@ -179,6 +179,20 @@
179	179	return now;
180	180	}
181	181
	182	+/**
	183	+ * get_cpu_idle_time_us - get the total idle time of a cpu
	184	+ * @cpu: CPU number to query
	185	+ * @last_update_time: variable to store update time in
	186	+ *
	187	+ * Return the cummulative idle time (since boot) for a given
	188	+ * CPU, in microseconds. The idle time returned includes
	189	+ * the iowait time (unlike what "top" and co report).
	190	+ *
	191	+ * This time is measured via accounting rather than sampling,
	192	+ * and is as accurate as ktime_get() is.
	193	+ *
	194	+ * This function returns -1 if NOHZ is not enabled.
	195	+ */
182	196	u64 get_cpu_idle_time_us(int cpu, u64 *last_update_time)
183	197	{
184	198	struct tick_sched *ts = &per_cpu(tick_cpu_sched, cpu);