Messages in this thread | | | From | Daniel Phillips <> | Subject | Re: 2.4.19pre1aa1 | Date | Sun, 3 Mar 2002 22:38:34 +0100 |
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On March 2, 2002 03:06 am, Andrea Arcangeli wrote: > On Thu, Feb 28, 2002 at 10:26:48PM -0500, Bill Davidsen wrote: > > rather than patches. But there are a lot more small machines (which I feel > > are better served by rmap) than large. I would like to leave the jury out > > I think there's quite some confusion going on from the rmap users, let's > clarify the facts. > > The rmap design in the VM is all about decreasing the complexity of > swap_out on the huge boxes (so it's all about saving CPU), by slowing > down a big lots of fast common paths like page faults and by paying with > some memory too. See the lmbench numbers posted by Randy after applying > rmap to see what I mean.
Do you know any reason why rmap must slow down the page fault fast, or are you just thinking about Rik's current implementation? Yes, rmap has to add a pte_chain entry there, but it can be a direct pointer in the unshared case and the spinlock looks like it can be avoided in the common case as well.
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