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Date: Fri, 16 May 2003 23:17:27 -0700
From: David Schultz <das@FreeBSD.ORG>
To: Peter Edwards <pmedwards@eircom.net>
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cc: current@FreeBSD.ORG
Subject: Re: vm_page_max_wired and gpg...
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On Thu, May 15, 2003, Peter Edwards wrote:
> The kernel has a "max wired pages" limit, that's set when the swapper
> starts up to be one third of physical memory. You can see this in
> src/sys/vm_pageout.c, on about line 1414:
> 
> > if (vm_page_max_wired == 0)
> >   vm_page_max_wired = cnt.v_free_count / 3;
> 
> This is pretty much a third of what you see at boot time (and in
> /var/log/messages or dmesg) for "avail memory = "
[...]
> For your purpose, making vm_page_max_wired a sysctl would probably
> fix the problem in the short term.

It could be made a tunable, but that's mostly just a footshooting
opportunity.  If you wire too much memory, the system will thrash
and possibly deadlock.  On the other hand, I suppose it could be
useful in systems with very little memory...