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From: David Mosberger <davidm@napali.hpl.hp.com>
To: linux-ia64@vger.kernel.org
Subject: RE: HUGEPAGE SIZE a boottime option
Date: Thu, 26 Feb 2004 05:18:57 +0000	[thread overview]
Message-ID: <16445.33217.472790.188648@napali.hpl.hp.com> (raw)
In-Reply-To: <20040220010731.GA28820@sgi.com>

>>>>> On Wed, 25 Feb 2004 17:26:25 -0800, "Chen, Kenneth W" <kenneth.w.chen@intel.com> said:

  Ken> We believe we have resolved all the remain issues, all critical
  Ken> speed path has been taken care of, i.e., vhpt hander and
  Ken> context switch.  There should be no performance penalty with
  Ken> this dynamic hugetlb page size feature.

What about huge-page page-faults?  Before, HPAGE_SHIFT, HPAGE_SIZE,
and HPAGE_MASK all were constant, now they have to be fetched from
memory/recalculated each time.  I suppose it's rare enough that it's
not worth worrying about but did you verify that there is at least not
anything really gross going on (like someone doing a modulo operation
against HPAGE_SIZE)?

How about replacing 0x8000000000000000 with (REGION_HPAGE <<
REGION_SHIFT) or a manifest constant defined to this value (perhaps
HUGETLB_REGION_ADDR)?

Why does the region register get initialized both in mm/init.c and
hugetlb_setup_sz()?  Couldn't this be done once in hugetlb_init()?

Other than that, the patch looks good to me.

	--david


  parent reply	other threads:[~2004-02-26  5:18 UTC|newest]

Thread overview: 15+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-02-20  1:07 HUGEPAGE SIZE a boottime option Jack Steiner
2004-02-20  2:35 ` David Mosberger
2004-02-20  4:00 ` Chen, Kenneth W
2004-02-20 19:36 ` Seth, Rohit
2004-02-22  5:27 ` Chris Wedgwood
2004-02-22 23:08 ` Jack Steiner
2004-02-23 16:19 ` Chen, Kenneth W
2004-02-23 16:26 ` Chen, Kenneth W
2004-02-23 18:52 ` David Mosberger
2004-02-23 18:58 ` Chen, Kenneth W
2004-02-24  4:05 ` Jack Steiner
2004-02-26  1:26 ` Chen, Kenneth W
2004-02-26  2:09 ` Chen, Kenneth W
2004-02-26  5:18 ` David Mosberger [this message]
2004-02-26 20:31 ` Chen, Kenneth W

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