Subject: Re: [PATCH 07/15] ftrace: fix event alignment: kvm:kvm_hv_hypercall
From: Steven Rostedt <rostedt@goodmis.org>
To: Avi Kivity <avi@redhat.com>
Cc: David Sharp <dhsharp@google.com>, linux-kernel@vger.kernel.org,
        mrubin@google.com, kvm-devel <kvm@vger.kernel.org>
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Date: Tue, 08 Mar 2011 18:55:41 -0500
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Hi Avi,

This patch set got lost in the shuffle, and I'm not looking to include
it.

On Wed, 2010-12-08 at 11:18 +0200, Avi Kivity wrote:
> On 12/07/2010 11:16 PM, David Sharp wrote:
> > >
> > >  I don't understand this.  Can you elaborate?  What does "32-bit addressable"
> > >  mean?
> >
> > The ring buffer gives you space that is a multiple of 4 bytes in
> > length, and 32-bit aligned. Therefore it is useless to attempt to
> > align the structure beyond 32-bit boundaries, eg, a 64-bit boundary,
> > because it is unpredictable if the memory the structure will be
> > written to is at a 64-bit boundary (addr % 8 could be 0 or 4).
> >
> > >  And "predicated on packing the event structures"?  Is the structure
> > >  __attribute__((packed)), or is it not?
> >
> > It is not packed in Linus' tree, but one of the patches before this
> > patch in this patch series adds __attribute__((packed)). This patch
> > assumes that the event packing patch has been applied. This patch
> > should not be applied if the packing patch is not (hence,
> > "predicated").
> 
> Thanks for the explanations, it makes sense now.
> 

Does this mean I can add your "Acked-by"?

-- Steve


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