Re: large page patch

Linus Torvalds (torvalds@transmeta.com)
Fri, 2 Aug 2002 03:23:39 +0000 (UTC)


In article <20020801.181944.09310618.davem@redhat.com>,
David S. Miller <davem@redhat.com> wrote:
> From: Andrew Morton <akpm@zip.com.au>
> Date: Thu, 01 Aug 2002 18:26:40 -0700
>
> "David S. Miller" wrote:
> > This is probably done to increase the likelyhood that 4MB page orders
> > are available. If we collapse 4MB pages deeper, they are less likely
> > to be broken up because smaller orders would be selected first.
>
> This is leakage from ia64, which supports up to 256k pages.
>
>Ummm, 4MB > 256K and even with a 4K PAGE_SIZE MAX_ORDER coalesces
>up to 4MB already :-)

That should be 256_M_ pages (13 bits of page size + 15 bits of MAX_ORDER
gives you 256MB max).

Linus
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