Date: Mon, 14 Mar 2005 13:50:21 -0800
From: "David S. Miller" <davem@davemloft.net>
To: Dave Hansen <haveblue@us.ibm.com>
Cc: akpm@osdl.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH 0/4] sparsemem intro patches
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On Mon, 14 Mar 2005 13:14:43 -0800
Dave Hansen <haveblue@us.ibm.com> wrote:

> Three of these are i386-only, but one of them reorganizes the macros
> used to manage the space in page->flags, and will affect all platforms.
> There are analogous patches to the i386 ones for ppc64, ia64, and
> x86_64, but those will be submitted by the normal arch maintainers.

Sparc64 uses some of the upper page->flags bits to store D-cache
flushing state.

Specifically, PG_arch_1 is used to set whether the page is scheduled
for delayed D-cache flushing, and bits 24 and up say which CPU the
CPU stores occurred on (and thus which CPU will get the cross-CPU
message to flush it's D-cache should the deferred flush actually
occur).

I imagine that since we don't support the domain stuff (yet) on sparc64,
your patches won't break things, but it is something to be aware of.
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