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    SubjectRe: [PATCH 00/28] Swap over NFS -v16
    > > mm-page_file_methods.patch
    > >
    > > This makes page_offset and others more expensive by adding a
    > > conditional jump to a function call that is not usually made.
    > >
    > > Why do swap pages have a different index to everyone else?
    > Because the page->index of an anonymous page is related to its (anon)vma
    > so that it satisfies the constraints for vm_normal_page().
    > The index in the swap file it totally unrelated and quite random. Hence
    > the swap-cache uses page->private to store it in.

    Yeah, and putting the condition into page_offset() will confuse code
    which uses it for finding the offset in the VMA or in a tmpfs file.

    So why not just have a separate page_swap_offset() function, used
    exclusively by swap_in/out()?


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      Last update: 2008-02-26 16:33    [W:0.017 / U:44.348 seconds]
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