Re: PAGE_SIZE on 64bit and 32bit machines

From: Yoav Artzi
Date: Mon Nov 12 2007 - 10:32:48 EST


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@xxxxxxxxx>
To: Yoav Artzi <yoavar@xxxxxxxxxxxxxx>
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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