[055/127] latencytop: fix per task accumulator

From: Greg KH
Date: Tue Dec 07 2010 - 21:10:05 EST


2.6.32-stable review patch. If anyone has any objections, please let us know.

------------------

From: Ken Chen <kenchen@xxxxxxxxxx>

commit 38715258aa2e8cd94bd4aafadc544e5104efd551 upstream.

Per task latencytop accumulator prematurely terminates due to erroneous
placement of latency_record_count. It should be incremented whenever a
new record is allocated instead of increment on every latencytop event.

Also fix search iterator to only search known record events instead of
blindly searching all pre-allocated space.

Signed-off-by: Ken Chen <kenchen@xxxxxxxxxx>
Reviewed-by: Arjan van de Ven <arjan@xxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

---
kernel/latencytop.c | 17 ++++++++---------
1 file changed, 8 insertions(+), 9 deletions(-)

--- a/kernel/latencytop.c
+++ b/kernel/latencytop.c
@@ -195,14 +195,7 @@ __account_scheduler_latency(struct task_

account_global_scheduler_latency(tsk, &lat);

- /*
- * short term hack; if we're > 32 we stop; future we recycle:
- */
- tsk->latency_record_count++;
- if (tsk->latency_record_count >= LT_SAVECOUNT)
- goto out_unlock;
-
- for (i = 0; i < LT_SAVECOUNT; i++) {
+ for (i = 0; i < tsk->latency_record_count; i++) {
struct latency_record *mylat;
int same = 1;

@@ -228,8 +221,14 @@ __account_scheduler_latency(struct task_
}
}

+ /*
+ * short term hack; if we're > 32 we stop; future we recycle:
+ */
+ if (tsk->latency_record_count >= LT_SAVECOUNT)
+ goto out_unlock;
+
/* Allocated a new one: */
- i = tsk->latency_record_count;
+ i = tsk->latency_record_count++;
memcpy(&tsk->latency_record[i], &lat, sizeof(struct latency_record));

out_unlock:


--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/