Re: A DMA patch for linux 2.2.9

Douglas Gilbert (dgilbert@interlog.com)
Wed, 07 Jul 1999 08:09:50 -0400

H.J. Lu wrote:
> Hi,
>
> We ran into the DMA memory allocation problem on 2GB machines. Here is
> a patch with this 2-pass memory allocation scheme. For DMA memory
> allocation, it will use the first available DMA memory. For none-DMA
> memory allocation, it will first try the none-DMA memory. If it fails,
> if will use the first available memory in the second pass. I am not
> sure how well it will work on low memory machines. Is there a better
> approach for this problem?

Interesting. It certainly addresses a serious problem
in the 2.2 series of kernels that causes OOM for
SCSI, sound and floppy devices.

Jaroslav Kysela <perex@suse.cz> posted a patch addressing
the same problem. It was titled: 'DMA page allocation' and
dated Wednesday 16th June 1999. He has set up a web page
about it at:
http://www.alsa-project.org/~perex/page_alloc.html

Perhaps you could compare notes.

Doug Gilbert

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