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From: Johannes Weiner <hannes@saeurebad.de>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>, Ingo Molnar <mingo@elte.hu>
Subject: [PATCH 2/3] softlockup: sanitize print-out limit checks
Date: Fri, 27 Jun 2008 02:04:47 +0200	[thread overview]
Message-ID: <20080627000805.279106291@saeurebad.de> (raw)
In-Reply-To: 20080627000445.346130358@saeurebad.de

[-- Attachment #1: softlockup-bogus-report-delay-checks.patch --]
[-- Type: text/plain, Size: 1063 bytes --]

The print_timestamp can never be bigger than the touch_timestamp, at
maximum it can be equal.  And if it is, the second check for
touch_timestamp + 1 bigger print_timestamp is always true, too.

The check for equality is sufficient as we proceed in one-second-steps
and are at least one second away from the last print-out if we have
another timestamp.

Signed-off-by: Johannes Weiner <hannes@saeurebad.de>
---
 kernel/softlockup.c |    8 ++++----
 1 file changed, 4 insertions(+), 4 deletions(-)

--- a/kernel/softlockup.c
+++ b/kernel/softlockup.c
@@ -93,11 +93,11 @@ void softlockup_tick(void)
 	print_timestamp = per_cpu(print_timestamp, this_cpu);
 
 	/* report at most once a second */
-	if ((print_timestamp >= touch_timestamp &&
-			print_timestamp < (touch_timestamp + 1)) ||
-			did_panic || !per_cpu(watchdog_task, this_cpu)) {
+	if (print_timestamp == touch_timestamp)
+		return;
+
+	if (did_panic || !per_cpu(watchdog_task, this_cpu))
 		return;
-	}
 
 	/* do not print during early bootup: */
 	if (unlikely(system_state != SYSTEM_RUNNING)) {

-- 


  parent reply	other threads:[~2008-06-27  0:16 UTC|newest]

Thread overview: 14+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-06-27  0:04 [PATCH 0/3] softlockup fixlets Johannes Weiner
2008-06-27  0:04 ` [PATCH 1/3] softlockup: only reset timestamp from NMI code Johannes Weiner
2008-06-27  0:04 ` Johannes Weiner [this message]
2008-06-27  0:04 ` [PATCH 3/3] softlockup: fix watchdog task wakeup frequency Johannes Weiner
2008-06-27 12:03   ` Ingo Molnar
2008-06-27 12:33     ` Johannes Weiner
2008-06-27 12:43       ` Ingo Molnar
2008-06-27 13:07         ` Johannes Weiner
2008-06-28  0:45           ` Johannes Weiner
2008-06-30 13:08             ` Ingo Molnar
2008-07-01  5:40               ` Johannes Weiner
2008-07-01  6:11                 ` Ingo Molnar
2008-07-01  7:12                   ` Johannes Weiner
2008-07-01  7:22                     ` Ingo Molnar

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