sched, timer: Provide an atomic 'struct task_cputime' data structure

This patch adds an atomic variant of the 'struct task_cputime' data structure,
which can be used to store and update task_cputime statistics without
needing to do locking.

Suggested-by: Ingo Molnar <[email protected]>
Signed-off-by: Jason Low <[email protected]>
Signed-off-by: Peter Zijlstra (Intel) <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Rik van Riel <[email protected]>
Cc: Andrew Morton <[email protected]>
Cc: Aswin Chandramouleeswaran <[email protected]>
Cc: Borislav Petkov <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Frederic Weisbecker <[email protected]>
Cc: H. Peter Anvin <[email protected]>
Cc: Linus Torvalds <[email protected]>
Cc: Mel Gorman <[email protected]>
Cc: Mike Galbraith <[email protected]>
Cc: Oleg Nesterov <[email protected]>
Cc: Paul E. McKenney <[email protected]>
Cc: Peter Zijlstra <[email protected]>
Cc: Preeti U Murthy <[email protected]>
Cc: Scott J Norton <[email protected]>
Cc: Steven Rostedt <[email protected]>
Cc: Waiman Long <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Ingo Molnar <[email protected]>

1 files changed, 17 insertions, 0 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index a45874c3fab6..6eb78cd45da7 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -572,6 +572,23 @@ struct task_cputime {
 		.sum_exec_runtime = 0,				\
 	}
 
+/*
+ * This is the atomic variant of task_cputime, which can be used for
+ * storing and updating task_cputime statistics without locking.
+ */
+struct task_cputime_atomic {
+	atomic64_t utime;
+	atomic64_t stime;
+	atomic64_t sum_exec_runtime;
+};
+
+#define INIT_CPUTIME_ATOMIC \
+	(struct task_cputime_atomic) {				\
+		.utime = ATOMIC64_INIT(0),			\
+		.stime = ATOMIC64_INIT(0),			\
+		.sum_exec_runtime = ATOMIC64_INIT(0),		\
+	}
+
 #ifdef CONFIG_PREEMPT_COUNT
 #define PREEMPT_DISABLED	(1 + PREEMPT_ENABLED)
 #else