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Date:      Fri, 11 Jun 1999 13:55:04 +0100
From:      Roger Hardiman <roger@cs.strath.ac.uk>
To:        hackers@freebsd.org, new-bus-arch@bostonradio.org
Subject:   KLD bt848 driver and vm_page_alloc_contig
Message-ID:  <37610728.7640C257@cs.strath.ac.uk>

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Hi,

Is there a way to fix
  vm_page_alloc_contig()
so it can allocate contiguous memory once userland has got up
and running and memory has been fragmented/filled.


I've finished porting the bt848 driver to the newbus framework.
You can load/unload the driver with kldload and kldunload.
Great for testing. Load test, unload, recompile, repeat...

However, the driver needs about 2 meg of contiguous memory allocating.
It must be contiguous as hardware writes directly into it.
(same applies to the meteor driver and probably some of the sound card
drivers)

I can start X, and load the 'bktr' driver.
But once I run a few apps, and memory fills up, I can no longer allocate
the
contiguous memory required.

Clearly the kernel would need to swap out user process memory pages to
make
room for the contigous memory vm_page_alloc_contig() requires.


Can this be done?


Bye
Roger
--
Roger Hardiman
Strathclyde Uni Telepresence Research Group, Glasgow, Scotland.
http://telepresence.dmem.strath.ac.uk      0141 548 2897
roger@cs.strath.ac.uk


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