Re: Linux and physical memory

David S. Miller (davem@dm.cobaltmicro.com)
Mon, 18 Jan 1999 23:48:48 -0800


From: Jakub Jelinek <jj@sunsite.ms.mff.cuni.cz>
Date: Tue, 19 Jan 1999 08:37:54 +0100 (CET)

Also, if you add PG_highmem, I bet current page_alloc will suck
badly (even the way how is PG_dma done now is very unefficient).

No, it's actually pretty simple. The difference is that PG_dma "must"
get a PG_dma page. Whereas PG_highmem says such a page is "OK" if
that is what you happen to find.

This means that all that is needed is to treat PG_highmem pages as if
you didn't see them at all if the __get_free_pages() does not say that
they are ok.

I don't claim that this will be fast, but it will be simple and work.

Later,
David S. Miller
davem@dm.cobaltmicro.com

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