Messages in this thread | | | Date | Thu, 26 Aug 1999 14:13:53 +0200 | From | Benjamin Herrenschmidt <> | Subject | Re: Cache incoherencies |
| |
On Thu, Aug 26, 1999, Rogier Wolff <R.E.Wolff@BitWizard.nl> wrote:
>On the other hand, having __get_free_pages allow for various >attributes that belong to pages would be a good idea. It should for >example allow you to specify that you require a DMA-able page on a PC. >(You're all thinking about pages below 16M, right? Good. I was talking >about pages below 4G for a PCI bus-mastering card...) > >As a user of __get_free_pages or kmalloc, you should be able to specify >"I NEED DMA" or "I prefer non-DMA". > >__get_free_pages should call an "exception" routine when it gets "none >available" on a request. This will happen if no "flagged as >uncacheable" pages happen to be free, and the exception routine will >map a page uncacheable, and return that. The exception routine for >"normal" pages may look to see if there are any free uncached pages >and claim them back...
Sounds interesting, but implementing this is beyond my current knowledge of Linux internals.
I think I'll first implement vmalloc_uncached for my specific machine, so at least I can make sure I have a working net driver for now, but I'll need help to implement the kind of solution you are talking about.
-- Perso. e-mail: <mailto:bh40@calva.net> Work e-mail: <mailto:benh@mipsys.com> BenH. Web : <http://calvaweb.calvacom.fr/bh40/>
- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.rutgers.edu Please read the FAQ at http://www.tux.org/lkml/
| |