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[Xen-devel] Re: [rfc] [patch] grant_entry.flags accessors

To: Hollis Blanchard <hollisb@xxxxxxxxxx>
Subject: [Xen-devel] Re: [rfc] [patch] grant_entry.flags accessors
From: Keir Fraser <Keir.Fraser@xxxxxxxxxxxx>
Date: Tue, 27 Jun 2006 11:39:28 +0100
Cc: xen-devel <xen-devel@xxxxxxxxxxxxxxxxxxx>, xen-ppc-devel <xen-ppc-devel@xxxxxxxxxxxxxxxxxxx>
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On 23 Jun 2006, at 22:19, Hollis Blanchard wrote:

These patches are similar to changeset 10747 (which added
vcpu_mark_events_pending), in that they allow PPC to work around some
unusually-sized atomic operations, this time in the grant table driver.

Keir, do you think it's a good idea to make a wiki page to list where
the current ABI is causing problems? That way, when the ABI opens up
again (Xen 4?), we'll have a list of places to fix?

Anyways, I expect you'll have alternate name/interface suggestions in
the patches, so they're just RFC for now.

You should be able to hide all this behind the generic atomic operations without slowing down sufficiently aligned operations at all.

e.g. something like:
define clear_bit(p,i) ((alignof(p)>=alignof(long)) ? clear_bit(p,i) : clear_bit_unaligned(p,i))

 -- Keir

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