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To: hutton@ISI.EDU
cc: dyson@FreeBSD.ORG, hackers@FreeBSD.ORG
Subject: Re: vm_page_alloc_contig again 
In-reply-to: Your message of "Mon, 14 Jul 1997 17:02:03 PDT."
             <199707150003.AA14675@zephyr.isi.edu> 
From: David Greenman <dg@root.com>
Reply-To: dg@root.com
Date: Mon, 14 Jul 1997 18:10:03 -0700
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>
>> vm_page_alloc_contig works best before the system is fully up.  It is used
>> to allocate medium sized contiguous chunks at bootup time.
>> 
>
>we use vm_page_alloc_contig in a device driver...so it is at boot time and it 
>is a small chunk - 1/2 meg.
>
>It allocates ok and the device driver works but we suspect that the pages 
>aren't (really) wired down. We see a page fault and the machine panics when we 
>are forwarding packets through the NIC from another NIC on the same host. Is 
>there a known problem with the pages not being wired down once allocated by 
>vm_page_alloc_contig at boot time?

   There aren't any known problems and several other device drivers use the
function to allocate memory without any trouble. Memory allocated to the
kernel is never reclaimed by the pagedaemon, so I suspect you've got a bug
somewhere in your code.

-DG

David Greenman
Core-team/Principal Architect, The FreeBSD Project