[PATCH] per-task-delay-accounting: cpu delay collection via schedstats

Make the task-related schedstats functions callable by delay accounting even
if schedstats collection isn't turned on.  This removes the dependency of
delay accounting on schedstats.

Signed-off-by: Chandra Seetharaman <sekharan@us.ibm.com>
Signed-off-by: Shailabh Nagar <nagar@watson.ibm.com>
Signed-off-by: Balbir Singh <balbir@in.ibm.com>
Cc: Jes Sorensen <jes@sgi.com>
Cc: Peter Chubb <peterc@gelato.unsw.edu.au>
Cc: Erich Focht <efocht@ess.nec.de>
Cc: Levent Serinol <lserinol@gmail.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

1 files changed, 17 insertions, 3 deletions

diff --git a/include/linux/sched.h b/include/linux/sched.h
index 2f43f1fb7de7..f751062d89a2 100644
--- a/include/linux/sched.h
+++ b/include/linux/sched.h
@@ -537,7 +537,7 @@ extern struct user_struct root_user;
 struct backing_dev_info;
 struct reclaim_state;
 
-#ifdef CONFIG_SCHEDSTATS
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
 struct sched_info {
         /* cumulative counters */
         unsigned long   cpu_time,       /* time spent on the cpu */
@@ -548,9 +548,11 @@ struct sched_info {
         unsigned long   last_arrival,   /* when we last ran on a cpu */
                         last_queued;    /* when we were last queued to run */
 };
+#endif /* defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) */
 
+#ifdef CONFIG_SCHEDSTATS
 extern struct file_operations proc_schedstat_operations;
-#endif
+#endif /* CONFIG_SCHEDSTATS */
 
 #ifdef CONFIG_TASK_DELAY_ACCT
 struct task_delay_info {
@@ -580,7 +582,19 @@ struct task_delay_info {
         u32 swapin_count;       /* total count of the number of swapin block */
                                 /* io operations performed */
 };
+#endif  /* CONFIG_TASK_DELAY_ACCT */
+
+static inline int sched_info_on(void)
+{
+#ifdef CONFIG_SCHEDSTATS
+        return 1;
+#elif defined(CONFIG_TASK_DELAY_ACCT)
+        extern int delayacct_on;
+        return delayacct_on;
+#else
+        return 0;
 #endif
+}
 
 enum idle_type
 {
@@ -777,7 +791,7 @@ struct task_struct {
         cpumask_t cpus_allowed;
         unsigned int time_slice, first_time_slice;
 
-#ifdef CONFIG_SCHEDSTATS
+#if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT)
         struct sched_info sched_info;
 #endif