[tip:perf/urgent] watchdog: Fix rounding bug in get_sample_period()

[tip-bot for Mandeep Singh Baines]

Commit-ID:  824c6b7f6294101f30e141117def224a56c203e6
Gitweb:     http://git.kernel.org/tip/824c6b7f6294101f30e141117def224a56c203e6
Author:     Mandeep Singh Baines <msb@xxxxxxxxxxxx>
AuthorDate: Sun, 22 May 2011 22:10:20 -0700
Committer:  Ingo Molnar <mingo@xxxxxxx>
CommitDate: Mon, 23 May 2011 11:58:58 +0200

watchdog: Fix rounding bug in get_sample_period()

In get_sample_period(), softlockup_thresh is integer divided by
5 before the multiplication by NSEC_PER_SEC. This results in
softlockup_thresh being rounded down to the nearest integer
multiple of 5.

For example, a softlockup_thresh of 4 rounds down to 0.

Signed-off-by: Mandeep Singh Baines <msb@xxxxxxxxxxxx>
Cc: Marcin Slusarz <marcin.slusarz@xxxxxxxxx>
Cc: Don Zickus <dzickus@xxxxxxxxxx>
Cc: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Frederic Weisbecker <fweisbec@xxxxxxxxx>
Link: http://lkml.kernel.org/r/1306127423-3347-1-git-send-email-msb@xxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxx>
---
 kernel/watchdog.c |    2 +-
 1 files changed, 1 insertions(+), 1 deletions(-)

diff --git a/kernel/watchdog.c b/kernel/watchdog.c
index 14733d4..a06972d 100644
--- a/kernel/watchdog.c
+++ b/kernel/watchdog.c
@@ -110,7 +110,7 @@ static unsigned long get_sample_period(void)
 	 * increment before the hardlockup detector generates
 	 * a warning
 	 */
-	return softlockup_thresh / 5 * NSEC_PER_SEC;
+	return softlockup_thresh * (NSEC_PER_SEC / 5);
 }
 
 /* Commands for resetting the watchdog */
--
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/