Re: mm question

volodya@mindspring.com
Mon, 10 Dec 2001 10:03:47 -0500 (EST)


On Mon, 10 Dec 2001, Alan Cox wrote:

> > It does not have to be contiguous. I was thinking of simply starting with
> > the smallest address and trying to free the pages until the needed amount
> > is available. But I have no idea how to properly do locking or force the
> > page to be swapped out or something.
>
> You can simply get_free_page() 300K of pages. However you can't land them
> in a given band other than the existing "below 16Mb" "below 4Gb" "anywhere"
> bands.

Right, but then my card refuses to dma into anything with address smaller
than 04000000.

I have thought of doing get_free_page until I have enough of pages with
large addresses (and then free all the small ones as 64mb is a finite
amount) but this would place a big load on the system during buffer
allocation.

I was hoping for something more elegant, but I am not adverse to writing
my own get_free_page_from_range().

Vladimir Dergachev

>
> Alan
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