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    SubjectRe: fork: out of memory
    On Wed, 26 Nov 1997, Jan Echternach wrote:

    > On 26 November 1997, Mike Jagdis <> wrote:
    > > Paging *is* on in the kernel. It isn't so much a case of the kernel
    > > seeing contiguous memory as of devices seeing *physically*
    > > contiguous memory. There are a few case where we know nothing
    > > will want to do DMA to a multi-page region and in such cases we
    > > could use vmalloc (which already exists) but that has a relatively
    > > heavy set up / tear down penalty so better solutions that don't
    > > use vmalloc are prefered. Vmalloc doesn't help the problem that
    > > much anyway - most of the big page requests are for things like
    > > floppy buffers and sound buffers which have to be physically
    > > contiguous for DMA.
    > But if we need a DMA buffer that is physically contiguous can't we
    > just move non-DMA pages around and adjust the page tables such that
    > logical addresses stay the same?

    Memory is getting so inexpensive in some environments, wouldn't it make
    sense to have an option to reserve DMA-able memory at init time? With 16
    megs going for $60, it is worth setting aside 4megs or 8 megs which would
    have to be specially requested.

    john alvord

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