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    SubjectRe: [PATCH] Rmap speedup
    Rik van Riel wrote:
    > On Mon, 5 Aug 2002, Daniel Phillips wrote:
    > > > Despite the fact that the number of pte_chain references in
    > > > page_add/remove_rmap now just averages two in that test.
    > >
    > > It's weird that it only averages two. It's a four way and your running
    > > 10 in parallel, plus a process to watch for completion, right?
    > I explained this one in the comment above the declaration of
    > struct pte_chain ;)
    > * A singly linked list should be fine for most, if not all, workloads.
    > * On fork-after-exec the mapping we'll be removing will still be near
    > * the start of the list, on mixed application systems the short-lived
    > * processes will have their mappings near the start of the list and
    > * in systems with long-lived applications the relative overhead of
    > * exit() will be lower since the applications are long-lived.

    I don't think so - the list walks in there are fairly long.
    What seems to be happening is that, as Daniel mentioned,
    all the pte_chains for page N happen to have good locality
    with the pte_chains for page N+1. Like parallel lines.

    That might not hold up for longer-lived processes, slab cache
    fragmentation, longer chains, etc...
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