per-task-delay-accounting: update taskstats for memory reclaim delay

Add members for memory reclaim delay to taskstats, and accumulate them in
__delayacct_add_tsk() .
Signed-off-by: Keika Kobayashi <kobayashi.kk@ncos.nec.co.jp>
Cc: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

Documentation/accounting/taskstats-struct.txt

@@ -26,6 +26,8 @@ There are three different groups of fields in the struct taskstats:
 
 5) Time accounting for SMT machines
 
+6) Extended delay accounting fields for memory reclaim
+
 Future extension should add fields to the end of the taskstats struct, and
 should not change the relative position of each field within the struct.
 
@@ -170,4 +172,9 @@ struct taskstats {
 	__u64	ac_utimescaled;		/* utime scaled on frequency etc */
 	__u64	ac_stimescaled;		/* stime scaled on frequency etc */
 	__u64	cpu_scaled_run_real_total; /* scaled cpu_run_real_total */
+
+6) Extended delay accounting fields for memory reclaim
+	/* Delay waiting for memory reclaim */
+	__u64	freepages_count;
+	__u64	freepages_delay_total;
 }

include/linux/taskstats.h

@@ -31,7 +31,7 @@
  */
 
 
-#define TASKSTATS_VERSION	6
+#define TASKSTATS_VERSION	7
 #define TS_COMM_LEN		32	/* should be >= TASK_COMM_LEN
 					 * in linux/sched.h */
 
@@ -157,6 +157,10 @@ struct taskstats {
 	__u64	ac_utimescaled;		/* utime scaled on frequency etc */
 	__u64	ac_stimescaled;		/* stime scaled on frequency etc */
 	__u64	cpu_scaled_run_real_total; /* scaled cpu_run_real_total */
+
+	/* Delay waiting for memory reclaim */
+	__u64	freepages_count;
+	__u64	freepages_delay_total;
 };
 
 

kernel/delayacct.c

@@ -145,8 +145,11 @@ int __delayacct_add_tsk(struct taskstats *d, struct task_struct *tsk)
 	d->blkio_delay_total = (tmp < d->blkio_delay_total) ? 0 : tmp;
 	tmp = d->swapin_delay_total + tsk->delays->swapin_delay;
 	d->swapin_delay_total = (tmp < d->swapin_delay_total) ? 0 : tmp;
+	tmp = d->freepages_delay_total + tsk->delays->freepages_delay;
+	d->freepages_delay_total = (tmp < d->freepages_delay_total) ? 0 : tmp;
 	d->blkio_count += tsk->delays->blkio_count;
 	d->swapin_count += tsk->delays->swapin_count;
+	d->freepages_count += tsk->delays->freepages_count;
 	spin_unlock_irqrestore(&tsk->delays->lock, flags);
 
 done: