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    SubjectRe: missing madvise functionality
    Eric Dumazet wrote:

    > Well, I believe this one is too expensive. I was thinking of a light one :

    This one seems worse. Passing your vm_area_cache around everywhere, which
    is just intrusive and dangerous because ot becomes decoupled from the mm
    struct you are passing around. Watch this:

    > @@ -1638,7 +1652,7 @@ find_extend_vma(struct mm_struct * mm, u
    > unsigned long start;
    > addr &= PAGE_MASK;
    > - vma = find_vma(mm,addr);
    > + vma = find_vma(mm,addr,&current->vmacache);
    > if (!vma)
    > return NULL;
    > if (vma->vm_start <= addr)

    So now you can have current calling find_extend_vma on someone else's mm
    but using their cache. So you're going to return current's vma, or current
    is going to get one of mm's vmas in its cache :P

    SUSE Labs, Novell Inc.
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      Last update: 2007-04-04 12:09    [W:0.027 / U:11.844 seconds]
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