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From: David Mosberger <davidm@napali.hpl.hp.com>
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Date: Fri, 2 Aug 2002 21:17:45 -0700
To: Linus Torvalds <torvalds@transmeta.com>
Cc: <davidm@hpl.hp.com>, Gerrit Huizenga <gh@us.ibm.com>,
       Hubertus Franke <frankeh@watson.ibm.com>, <Martin.Bligh@us.ibm.com>,
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Subject: Re: large page patch (fwd) (fwd) 
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>>>>> On Fri, 2 Aug 2002 20:32:10 -0700 (PDT), Linus Torvalds <torvalds@transmeta.com> said:

  >> And since superpages quickly become counter-productive in
  >> tight-memory situations anyhow, this seems like a very reasonable
  >> approach.

  Linus> Ehh.. The only people who are _really_ asking for the
  Linus> superpages want almost nothing _but_ superpages. They are
  Linus> willing to use 80% of all memory for just superpages.

  Linus> Yes, it's Oracle etc, and the whole point for these users is
  Linus> to avoid having any OS memory allocation for these areas.

My terminology is perhaps a bit too subtle: I user "superpage"
exclusively for the case where multiple pages get coalesced into a
larger page.  The "large page" ("huge page") case that you were
talking about is different, since pages never get demoted or promoted.

I wasn't disagreeing with your case for separate large page syscalls.
Those syscalls certainly simplify implementation and, as you point
out, it well may be the case that a transparent superpage scheme never
will be able to replace the former.

	--david
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