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From: David Gibson <david@gibson.dropbear.id.au>
To: Marcelo Tosatti <marcelo.tosatti@cyclades.com>
Cc: Andrew Morton <akpm@osdl.org>, Anton Blanchard <anton@samba.org>,
	Paul Mackerras <paulus@samba.org>,
	linuxppc64-dev@ozlabs.org, linux-kernel@vger.kernel.org
Subject: Re: [PPC64] Remove LARGE_PAGE_SHIFT constant
Date: Sat, 18 Sep 2004 09:46:56 +1000	[thread overview]
Message-ID: <20040917234656.GB23252@zax> (raw)
In-Reply-To: <20040917170328.GB2179@logos.cnet>

On Fri, Sep 17, 2004 at 02:03:28PM -0300, Marcelo Tosatti wrote:
> On Fri, Sep 17, 2004 at 11:13:20AM +1000, David Gibson wrote:
> > Andrew, please apply:
> > 
> > For historical reasons, ppc64 has ended up with two #defines for the
> > size of a large (16M) page: LARGE_PAGE_SHIFT and HPAGE_SHIFT.  This
> > patch removes LARGE_PAGE_SHIFT in favour of the more widely used
> > HPAGE_SHIFT.
> 
> Nitpicking, "LARGE_PAGE_xxx" is used by x86/x86_64:
> 
> #define LARGE_PAGE_MASK (~(LARGE_PAGE_SIZE-1))
> #define LARGE_PAGE_SIZE (1UL << PMD_SHIFT)
> 
> Wouldnt it be nice to keep consistency between archs?

Hrm... they are indeed there.  However *all* archs, including x86 and
x86_64 have HPAGE_SHIFT et al - it's used in generic code, so x86 has
the duplicate #defines as well.

Actually.. I guess the distinction is that LARGE_PAGE_* refer to the
hardware large page size, whereas HPAGE_SIZE refers to the software
page size used for hugetlbfs.  I think those are identical for all
arches at the moment, but they wouldn't have to be.

-- 
David Gibson			| For every complex problem there is a
david AT gibson.dropbear.id.au	| solution which is simple, neat and
				| wrong.
http://www.ozlabs.org/people/dgibson

      parent reply	other threads:[~2004-09-18  7:42 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2004-09-17  1:13 [PPC64] Remove LARGE_PAGE_SHIFT constant David Gibson
2004-09-17 17:03 ` Marcelo Tosatti
2004-09-17 18:40   ` Dave Hansen
2004-09-17 17:33     ` Marcelo Tosatti
2004-09-17 23:43       ` David Gibson
2004-09-17 21:23     ` Paul Mackerras
2004-09-17 23:46   ` David Gibson [this message]

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