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Re: block sizes > 4K ?? possible w/large page support?

To: xfs@xxxxxxxxxxx
Subject: Re: block sizes > 4K ?? possible w/large page support?
From: Stefan Ring <stefanrin@xxxxxxxxx>
Date: Mon, 11 Jun 2012 23:25:45 +0200
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> I know we can use hugepages with these sizes, but didn't know we can use this 
> as
> common usage. I tried to look at MM code and didn't find anything which would
> make PAGE_SIZE greater than 4096 (at least in x86), but well, I'm not a MM
> developer too.

Me neither, but so much I think I know. With rather recent kernels,
huge pages are used automatically for "normal" memory. There's a
background thread that tries to locate or create adjacent blocks of
memory and create huge pages from these.

But the normal page size as a unit of allocation is still 4KB, and
this will never change (with the current hardware). The page size of
4KB is hard-wired into the architecture, and I'm not aware of any
extension that allows to change that.

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