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    SubjectRe: deferred rss update instead of sloppy rss
    Christoph Lameter <clameter@sgi.com> wrote:
    >
    > On Mon, 22 Nov 2004, Andrew Morton wrote:
    >
    > > > The page fault code only increments rss. For larger transactions that
    > > > increase / decrease rss significantly the page_table_lock is taken and
    > > > mm->rss is updated directly. So no
    > > > gross inaccuracies can result.
    > >
    > > Sure. Take a million successive pagefaults and mm->rss is grossly
    > > inaccurate. Hence my suggestion that it be spilled into mm->rss
    > > periodically.
    >
    > It is spilled into mm->rss periodically. That is the whole point of the
    > patch.
    >
    > The timer tick occurs every 1 ms.

    That only works if the task happens to have the CPU when the timer tick
    occurs. There remains no theoretical upper bound to the error in mm->rss,
    and that's very easy to fix.
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