From: Avi Kivity <avi@redhat.com>
To: David Sharp <dhsharp@google.com>
Cc: rostedt@goodmis.org, linux-kernel@vger.kernel.org,
mrubin@google.com, kvm-devel <kvm@vger.kernel.org>
Subject: Re: [PATCH 07/15] ftrace: fix event alignment: kvm:kvm_hv_hypercall
Date: Wed, 08 Dec 2010 11:18:04 +0200 [thread overview]
Message-ID: <4CFF4D4C.2070002@redhat.com> (raw)
In-Reply-To: <AANLkTinK7Zqh=GfFLeyJLxA4u2ozyVj-Ja435iBJPV13@mail.gmail.com>
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.
--
error compiling committee.c: too many arguments to function
next prev parent reply other threads:[~2010-12-08 9:18 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <1291421609-14665-1-git-send-email-dhsharp@google.com>
[not found] ` <1291421609-14665-8-git-send-email-dhsharp@google.com>
2010-12-04 8:11 ` [PATCH 07/15] ftrace: fix event alignment: kvm:kvm_hv_hypercall Avi Kivity
2010-12-06 20:38 ` David Sharp
2010-12-07 9:22 ` Avi Kivity
2010-12-07 21:16 ` David Sharp
2010-12-08 9:18 ` Avi Kivity [this message]
2011-03-08 23:55 ` Steven Rostedt
2011-03-09 8:50 ` Avi Kivity
2011-03-09 12:54 ` Steven Rostedt
2011-03-09 13:01 ` Avi Kivity
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