Message-ID: <473DC10B.5000702@zytor.com>
Date: Fri, 16 Nov 2007 08:10:51 -0800
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Andi Kleen <ak@suse.de>
CC: William Lee Irwin III <wli@holomorphy.com>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       Jeremy Fitzhardinge <jeremy@goop.org>, Ingo Molnar <mingo@elte.hu>,
       Thomas Gleixner <tglx@linutronix.de>,
       Nick Piggin <nickpiggin@yahoo.com.au>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Why preallocate pmd in x86 32-bit PAE?
References: <473CC0AC.3020500@goop.org> <200711161216.46733.ak@suse.de> <473DBB0C.2060808@zytor.com> <200711161653.00824.ak@suse.de>
In-Reply-To: <200711161653.00824.ak@suse.de>
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Andi Kleen wrote:
> On Friday 16 November 2007 16:45:16 H. Peter Anvin wrote:
>> Andi Kleen wrote:
>>>> I think Jeremy's question was due to trying to reduce the 32/64-bit 
>>>> differences.  Performance-wise, it might add a small amount to user 
>>>> setup time (a typical 32-bit process will need all four, for the main 
>>>> binary, libraries, stack and kernel, respectively) 
>>> With the new top down mmap layout and standard 3:1 split it should typically 
>>> only need two.
>>>
>> Well, three with the kernel.
> 
> I didn't count kernel because it is always fixed anyways and about zero
> overhead for the normal setup case.
> 

Of course, but it was in the original list so...

	-hpa
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