linux-kernel - Re: PAGE_SIZE on 64bit and 32bit machines

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Date:	Mon, 12 Nov 2007 17:32:36 +0200
From:	Yoav Artzi <yoavar@...ckpoint.com>
To:	Jiri Slaby <jirislaby@...il.com>
CC:	linux-kernel@...r.kernel.org
Subject: Re: PAGE_SIZE on 64bit and 32bit machines

Well, since the size of the kernel stack is one page, I figured it will 
grow when switching to 64-bit, because some of the types grow and a 
similar flow/stack will be bigger in 64-bit in comparison to 32-bit.

Keeping the page size at 4kb and so keeping the stack at 4kb is a bit 
dangerous. Isn't it?

I know that using one page for a kernel stack is a optional feature, but:

a) It's a good feature

b) It's already used by major distros, e.g. Red Hat



-------- Original Message  --------

Subject: Re: PAGE_SIZE on 64bit and 32bit machines
From: Jiri Slaby <jirislaby@...il.com>
To: Yoav Artzi <yoavar@...ckpoint.com>
Date: Monday, November 12, 2007 5:14:17 PM

> On 11/12/2007 03:39 PM, Yoav Artzi wrote:
>   
>> According to my knowledge the PAGE_SIZE on 32bit architectures in 4KB.
>> Logically, the PAGE_SIZE on 64bit architectures should be 8KB. That's at
>> least the way I understand it. However, looking at the kernel code of
>> x86_64, I see the PAGE_SIZE is 4KB.
>>     
>
> Yes, it stood unchanged, the only difference is 4-level page tables.
>
>   
>> Can anyone explain to me what am I missing here?
>>     
>
> What led you to that it must be 8k?
>
> regards,
>   

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