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Date:      Thu, 25 Apr 2002 22:14:45 +0200
From:      Daniel Lang <dl@leo.org>
To:        freebsd-hackers@freebsd.org
Subject:   Re: 4.5-STABLE panicks ... KVA_PAGES the solution?
Message-ID:  <20020425201445.GA87785@atrbg11.informatik.tu-muenchen.de>

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Hi,

"Marc G. Fournier" wrote,
[..]
> So, I have plenty of swapspace left, lots of idle CPU and a whole whack
> 
> Someone suggested setting KVA_PAGES higher then the default for
> this, but, as this is a production server, and its not something I've ever
> played with, I'd like to know what the ramifications are ...
> 
> The server has 3Gig of RAM now ... according to opt_global.h,
> KVA_PAGES is set to 256 (1G) right now ... but if its 1G by default,  how
> does a system withi <1G of RAM in it "work"?  Or does this limit something
> else altogether?  I'm not finding any good 'reading material' on this so
> far, but from waht I found through a search, it seems that its recommended
> to be set to 768(3G) vs 256(1G)?
[..]

KVA_PAGES only determines the kernels _address space_, and thus
limits the amount of memory the kernel can use.
If you have lower system memory (which does not mean you don't have
less virtual memory, but even then...) its not a problem.

If you raise the KVA_PAGES to 3 GB, you have only 1GB left for
userland (again, address space, not memory), since 32bit 
architectures can only address 4GB of memory.

I'm not sure about your problem, maybe an increase of KVA_SPACE
could be a solution. Try 512 first, so you have 2GB for kernel 
and userland each.

HTH,
 Daniel
-- 
IRCnet: Mr-Spock     - Cool people don't move, they just hang around. -  
Daniel Lang * dl@leo.org * ++49 89 289 25735  * http://www.leo.org/~dl/

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