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DateThu, 29 Oct 1998 02:59:04 +0100 (CET)
FromMOLNAR Ingo <>
SubjectRe: 4MB pages and framebuffer access, x11perf results, 2.1.125
On Wed, 28 Oct 1998, Linus Torvalds wrote:

> Basically, anything that wants to do "large page" mappings of a frame
> buffer needs to use something that isn't standard mmap(). Whether that's a
> special flag to mmap() or something else is immaterial, but it needs to be
> done on a VMA basis, not on a page table basis. Because we need to
> disallow partial unmaps etc.

is something like vma->granularity sufficient? default is 4k, but can be
4m (2m) too. (I dont think a single VM_LARGE_PAGE flag is enough, with 3
level paging we have a theoretical possibility of 4G pages too.) But
putting this into the vma slows things down unnecessary i fear. Also,
there is no place for an integer 'granularity' in the mmap interface,
sigh.

-- mingo



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