svn commit: r184293 - in head/sys: amd64/amd64 i386/i386

John Baldwin jhb at freebsd.org
Mon Oct 27 12:21:26 PDT 2008


On Sunday 26 October 2008 02:58:04 pm Maxim Sobolev wrote:
> Author: sobomax
> Date: Sun Oct 26 18:58:04 2008
> New Revision: 184293
> URL: http://svn.freebsd.org/changeset/base/184293
> 
> Log:
>   Fix division by zero panic if kern.hz less than 32.
>   
>   MFC after:	1 day

This is wrong.  In the case you are worried about here, lapic_timer_hz is less 
than 128.  There is no way you are going to fire stathz 128 times per second 
from a timer running at < 128 hz.  You are effectively running stathz at 
lapic_timer_hz, so I would just set stathz = lapic_timer_hz in this case.  
Also, I would drop the extra {}'s to match style(9) as well as the existing 
style of the file.

> Modified:
>   head/sys/amd64/amd64/local_apic.c
>   head/sys/i386/i386/local_apic.c
> 
> Modified: head/sys/amd64/amd64/local_apic.c
> 
==============================================================================
> --- head/sys/amd64/amd64/local_apic.c	Sun Oct 26 17:20:37 2008	(r184292)
> +++ head/sys/amd64/amd64/local_apic.c	Sun Oct 26 18:58:04 2008	(r184293)
> @@ -401,7 +401,11 @@ lapic_setup_clock(void)
>  		lapic_timer_hz = hz * 2;
>  	else
>  		lapic_timer_hz = hz * 4;
> -	stathz = lapic_timer_hz / (lapic_timer_hz / 128);
> +	if (lapic_timer_hz < 128) {
> +		stathz = 128;
> +	} else {
> +		stathz = lapic_timer_hz / (lapic_timer_hz / 128);
> +	}
>  	profhz = lapic_timer_hz;
>  	lapic_timer_period = value / lapic_timer_hz;

-- 
John Baldwin


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