Re: [RFC 7/8] Enhance ramfs to support higher order pages

[Christoph Lameter]

On Fri, 20 Apr 2007, William Lee Irwin III wrote:
> 
> On Fri, Apr 20, 2007 at 09:30:30AM -0700, Christoph Lameter wrote:
> > We can map arbitrary 4k chunks of larger pages.
> 
> The core VM can do that but the hugetlb architectural code can't fall
> back to smaller page sizes. It also should not be put into a situation
> where it needs to do so given the semantics it must honor.

Wel we could potentially add a handle_pmd_fault to the vm...?
 
> Also, the final assertion is inaccurate. Fault handlers must instantiate
> pages of order mapping->order when faulting in a page of a file with
> a given pagecache size. The semantics of faulting and mmap()'ing are

Why? I agree that the page state of the higher order page must be updated 
consistently but one can use a pte to map a 4k chunk of a higher 
order page.


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