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From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Olivier MATZ <olivier.matz@6wind.com>
Cc: dev@dpdk.org
Subject: Re: [dpdk-dev] [memnic PATCH] linux: fix race condition
Date: Fri, 11 Apr 2014 08:47:01 -0700 (PDT)	[thread overview]
Message-ID: <21832480.IqanGZ8f4h@xps13> (raw)
In-Reply-To: <2469493.IGjSGz2PDr@platinum>

2014-04-11 11:41, Olivier MATZ:
> On Thursday, April 03, 2014 07:35:50 AM Hiroshi Shimamoto wrote:
> > From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> > 
> > Same as PMD, there is a race condition between host and guest
> > in the guest MEMNIC kernel driver.
> > 
> > Guest PMD                 Host
> > Thread-A     Thread-B     vSwitch
> > 
> >    |idx=0       |idx=0       |p[0] st!=2
> >    |cmpxchg     |            |
> >    |p[0] st->1  |            |
> >    |idx=1       |            |
> >    |fill data   |            |
> >    |p[0] st->2  |            |p[0] st==2
> >    |
> >    |            |            |receive data
> >    |            |            |p[0] st->0
> >    |            |
> >    |            |cmpxchg     |
> >    |            |success     |p[1] st!=2
> >    |            |p[0] st->1  |
> >    |            |
> >                   This is BAD
> > 
> > Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
> > ---
> > 
> >  linux/memnic_net.c | 9 +++++++++
> >  1 file changed, 9 insertions(+)
> 
> Reviewed-by: Olivier Matz <olivier.matz@6wind.com>

Applied

Thanks
-- 
Thomas

      reply	other threads:[~2014-04-11 15:45 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-04-03  7:35 Hiroshi Shimamoto
2014-04-11  9:41 ` Olivier MATZ
2014-04-11 15:47   ` Thomas Monjalon [this message]

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