linux-kernel - Re: 2.6.32-rc3: low mem - only 378MB on x86

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Date:	Mon, 5 Oct 2009 11:12:06 -0700 (PDT)
From:	Linus Torvalds <torvalds@...ux-foundation.org>
To:	Jeff Chua <jeff.chua.linux@...il.com>
cc:	Linux Kernel <linux-kernel@...r.kernel.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Hugh Dickins <hugh@...itas.com>
Subject: Re: 2.6.32-rc3: low mem - only 378MB on x86_32 with 64GB. Why?



On Mon, 5 Oct 2009, Jeff Chua wrote:
> 
> I've 3 systems with 4GB, 16GB and 64GB all running 32bit with these set:

Don't.

4GB is useable. 8GB is borderline. 16GB+ and nobody will care.

> # with 64GB
>              total       used       free     shared    buffers     cached
> Mem:         63995        524      63470          0          4        365
> Low:           378         32        345

All your low memory is used for the 'struct page' arrays that describe 
everything else.

> Anything I should do?

Use a 64-bit CPU and kernel or limit your memory to 8GB or so. No ifs, 
buts and maybe's.

			Linus
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