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    SubjectRe: [rfc] increase struct page size?!
    On Fri, 18 May 2007, Nick Piggin wrote:

    > However we don't have to let those 8 bytes go to waste: we can use them
    > to store the virtual address of the page, which kind of makes sense for
    > 64-bit, because they can likely to use complicated memory models.

    That is not a valid consideration anymore. There is virtual memmap update
    pending with the sparsemem folks that will simplify things.

    > Many batch operations on struct page are completely random, and as such, I
    > think it is better if each struct page fits completely into a single
    > cacheline even if it means being slightly larger.

    Right. That would simplify the calculations.

    > Don't let this space go to waste though, we can use page->virtual in order
    > to optimise page_address operations.

    page->virtual is a benefit if the page is cache hot. Otherwise it may
    cause a useless lookup.

    I wonder if there are other uses for the free space?

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