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Date: Fri, 13 Apr 2007 13:42:46 -0700
From: "H. Peter Anvin" <hpa@zytor.com>
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To: Jeremy Fitzhardinge <jeremy@goop.org>
CC: Zachary Amsden <zach@vmware.com>, Chris Wright <chrisw@sous-sol.org>,
       Andi Kleen <ak@suse.de>, "Eric W. Biederman" <ebiederm@xmission.com>,
       Linus Torvalds <torvalds@osdl.org>,
       Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: Crash while mapping memory in pagetable_init() (Was: Re: .config)
References: <20070413174913.GA25234@ezr.goop.org> <20070413183841.GP10574@sequoia.sous-sol.org> <20070413190552.GQ10574@sequoia.sous-sol.org> <461FD97B.1010203@goop.org> <461FE36D.1050205@vmware.com> <461FE77A.6020307@zytor.com> <461FE7C7.7050204@goop.org> <461FE8EC.3090304@zytor.com> <461FE9D1.1000803@goop.org>
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Jeremy Fitzhardinge wrote:
> H. Peter Anvin wrote:
>> I suggest, for clarity and to minimize bloat:
> 
> I think it would save a page, at most.  But OK.  (Also, if you're
> running !PAE, these pages will actually become part of the init_mm
> pagetable, so there's no memory wastage at all.)

Even with PSE?

However, the main reason I wanted it done that way is to avoid cargo 
cult programming; this makes it much clearer where the numbers actually 
come from.

>> #ifdef CONFIG_X86_PAE
>> # define PAGE_TABLE_SIZE    ((2048+4)*4096)
>> #else
>> # define PAGE_TABLE_SIZE    ((1024+1)*4096)
> 
> 1024 should be enough; the pgd is still swapper_pg_dir, and there are no
> pmds.

Check.

	-hpa