svn commit: r198868 - in head/sys: amd64/amd64 i386/i386

[Kostik Belousov]

On Wed, Nov 04, 2009 at 01:49:41PM +0100, Attilio Rao wrote:
> 2009/11/4 Ed Schouten <ed at 80386.nl>:
> > Hi Attilio,
> >
> > * Attilio Rao <attilio at FreeBSD.org> wrote:
> >> Opteron rev E family of processor expose a bug where, in very rare
> >> ocassions, memory barriers semantic is not honoured by the hardware
> >> itself. As a result, some random breakage can happen in uninvestigable
> >> ways (for further explanation see at the content of the commit itself).
> >
> > Ooh. Sounds like an interesting bug.
> >
> > The bug doesn't manifest itself on UP, right? If so, maybe we should add
> > some very short instructions to the warning on how to disable SMP.
> 
> Due to the semantic of the bug, I think that it can manifest itself on
> UP and a memory barrier failing on UP means that PREEMPTION can blow
> up. Considering this I wouldn't suggest anything different between the
> UP vs SMP case.

CPU is always self-consistent, isn't it ?

Also, I very much dislike idea of making our kernel a collection of
references to the man pages and URLs, esp. when URL point to the
resource not controlled by the project.
-------------- next part --------------
A non-text attachment was scrubbed...
Name: not available
Type: application/pgp-signature
Size: 196 bytes
Desc: not available
Url : http://lists.freebsd.org/pipermail/svn-src-head/attachments/20091104/c85a4b99/attachment.pgp