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From: "H. Peter Anvin" <hpa@zytor.com>
To: lkml@morethan.org
Cc: Jeremy Fitzhardinge <jeremy@goop.org>,
	linux-kernel@vger.kernel.org,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	the arch/x86 maintainers <x86@kernel.org>,
	Andi Kleen <ak@linux.intel.com>
Subject: Re: [Bug Fix]: Do 32-bit table calculations in pre-processor
Date: Fri, 03 Jul 2009 12:48:44 -0700	[thread overview]
Message-ID: <4A4E609C.5030608@zytor.com> (raw)
In-Reply-To: <200907031441.04604.lkml@morethan.org>

Michael S. Zick wrote:
> 
> Good point: (1<<(32-PAGE_SIFT)) would handle other than 4k pages.
> 
> I just hardcoded it as a working example of the change from setting
> the page table size by design rather than numeric error.
> 

As Jeremy pointed out, it's not wrong as written.  gas by design uses
arbitrary-precision arithmetic, and even if it didn't, it would still be
correct: (1 << 32) would collapse to 0, so all the rest of the
calculations would still be right.

Any way you can dump out this value from the vmlinux file (nm vmlinux |
grep MAPPING_BEYOND_END) in both cases?  What version of as/binutils do
you have installed?

> And yes, it has 512Mbyte of ram, so 1/2Mbyte page table sounds right to me.

/proc/cpuinfo, please?

	-hpa

-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.


  reply	other threads:[~2009-07-03 19:53 UTC|newest]

Thread overview: 30+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2009-07-03 18:14 [Bug Fix]: Do 32-bit table calculations in pre-processor Michael S. Zick
2009-07-03 18:27 ` Andi Kleen
2009-07-03 18:38   ` Michael S. Zick
2009-07-03 19:08     ` Jeremy Fitzhardinge
2009-07-03 19:13       ` Michael S. Zick
2009-07-03 19:30         ` Jeremy Fitzhardinge
2009-07-03 20:03           ` Michael S. Zick
2009-07-03 18:56 ` Jeremy Fitzhardinge
2009-07-03 18:57 ` Jeremy Fitzhardinge
2009-07-03 19:03   ` Michael S. Zick
2009-07-03 19:11     ` Jeremy Fitzhardinge
2009-07-03 19:18       ` H. Peter Anvin
2009-07-03 19:46         ` Michael S. Zick
2009-07-03 20:00           ` H. Peter Anvin
2009-07-03 19:14     ` H. Peter Anvin
2009-07-03 19:41       ` Michael S. Zick
2009-07-03 19:48         ` H. Peter Anvin [this message]
2009-07-03 20:38           ` Michael S. Zick
2009-07-03 20:40             ` H. Peter Anvin
2009-07-03 21:02               ` Michael S. Zick
2009-07-03 22:33                 ` H. Peter Anvin
2009-07-04  0:05                   ` Michael S. Zick
2009-07-04  0:11                     ` H. Peter Anvin
2009-07-03 22:01               ` Michael S. Zick
2009-07-04 13:23       ` Michael S. Zick
2009-07-03 19:33     ` Jeremy Fitzhardinge
2009-07-03 20:07 ` Yinghai Lu
2009-07-03 20:08   ` Yinghai Lu
2009-07-03 20:48     ` Michael S. Zick
2009-07-03 20:45   ` Michael S. Zick

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