Messages in this thread | | | Date | Fri, 16 Jan 2009 11:57:07 +0000 | From | "Jan Beulich" <> | Subject | Re: [PATCH] x86: simplify HIGHMEM-related Kconfig entries |
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>>> "H. Peter Anvin" <hpa@zytor.com> 15.01.09 18:10 >>> >Ingo Molnar wrote: >>>> >>>> No highmem - No highmem, no PAE >>>> HIGHMEM4G - Highmem, no PAE >>>> HIGHMEM64G - Highmem, PAE >>>> >>>> So X86_PAE and HIGHMEM4G is a bit of a contradiction. I haven't looked >>>> at the logic in detail, or remember offhand if there have been any >>>> weakening of the definitions above; e.g. someone could have implemented >>>> a way to do PAE without highmem, to get access to the NX bits. >>> Exactly - .23 made PAE an independently selectable option (in >>> particular, the no-highmem+PAE combination is now valid), but I can't >>> see why it added the !HIGHMEM4G dependency. >> >> There's no deep reason, it just has never really been tested that way. I >> think we should try it. > >If so, what would be the difference between HIGHMEM4G and HIGHMEM64G in >that case at all?
For example being able to select the DMADEVICES config option.
Jan
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