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Date: Mon, 27 Oct 2008 12:37:00 -0700
From: Maxim Sobolev <sobomax@FreeBSD.org>
Organization: Sippy Software, Inc.
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To: John Baldwin <jhb@FreeBSD.org>
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Cc: svn-src-head@FreeBSD.org, svn-src-all@FreeBSD.org,
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Subject: Re: svn commit: r184293 - in head/sys: amd64/amd64 i386/i386
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John Baldwin wrote:
> 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.

It might be wrong, but it's better than division by zero panic. And it 
actually works, check this screenshot:

http://sobomax.sippysoft.com/~sobomax/ScreenShot362.png

[ssp-root@sippy ~]$ sysctl -a | grep hz
kern.clockrate: { hz = 10, tick = 100000, profhz = 40, stathz = 128 }

As for the style(9), I am not really sure that applies, the exact quote:

<quote>
Space after keywords (if, while, for, return, switch).  No braces (`{'
and `}') are used for control statements with zero or only a single
statement unless that statement is more than a single line in which case
they are permitted.  Forever loops are done with for's, not while's.
</quote>

To me the following if:

if ()
   stmt1;
else
   stmt2;

falls into the category of statements with more than single line (3 in 
this case), so that {} is appropriate. So that either my change is OK, 
or style(9) needs to be clarified to include if/else explicitly.

-Maxim