Re: overlaping printk

[Andrew Morton <akpm@osdl.org>]

Ingo Molnar <mingo@elte.hu> wrote:
>
> i've attached a new patch that does what Andi suggested too - 
> timestamping of the oopses. This way we will zap no sooner than 10 
> seconds after the first oops.

I think that will do the wrong thing between 23 and 47 days uptime because
time_after() will return an incorrect answer.

How's this look?




- Bump the timeout to 30 seconds - 9600 baud is slow.

- Handle jiffy wraps: change the logic so that we only skip the lockbust if
  the current time is within 30 seconds of the previous lockbusting attempt.



---

 25-akpm/kernel/printk.c |   11 ++++++-----
 1 files changed, 6 insertions(+), 5 deletions(-)

diff -puN kernel/printk.c~mangled-printk-oops-output-fix-tweaks kernel/printk.c
--- 25/kernel/printk.c~mangled-printk-oops-output-fix-tweaks	Thu May 20 16:01:53 2004
+++ 25-akpm/kernel/printk.c	Thu May 20 16:10:32 2004
@@ -55,9 +55,6 @@ EXPORT_SYMBOL(console_printk);
 
 int oops_in_progress;
 
-/* zap spinlocks only once: */
-unsigned long oops_timestamp;
-
 /*
  * console_sem protects the console_drivers list, and also
  * provides serialisation for access to the entire console
@@ -479,10 +476,14 @@ static void emit_log_char(char c)
  * every 10 seconds, to leave time for slow consoles to print a
  * full oops.
  */
-static inline void zap_locks(void)
+static void zap_locks(void)
 {
-	if (!time_after(jiffies, oops_timestamp + 10*HZ))
+	static unsigned long oops_timestamp;
+
+	if (time_after_eq(jiffies, oops_timestamp) &&
+			!time_after(jiffies, oops_timestamp + 30*HZ))
 		return;
+
 	oops_timestamp = jiffies;
 
 	/* If a crash is occurring, make sure we can't deadlock */

_