From: Olivier MATZ <olivier.matz@6wind.com>
To: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>, Hayato Momma <h-momma@ce.jp.nec.com>
Subject: Re: [dpdk-dev] [memnic PATCH 1/5] pmd: fix race condition
Date: Wed, 26 Mar 2014 17:44:23 +0100 [thread overview]
Message-ID: <533303E7.8050206@6wind.com> (raw)
In-Reply-To: <7F861DC0615E0C47A872E6F3C5FCDDBD01073AD6@BPXM14GP.gisp.nec.co.jp>
Hi Hiroshi-san,
Please see my comments below.
On 03/11/2014 06:37 AM, Hiroshi Shimamoto wrote:
> From: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
>
> There is a race condition, on transmit to vSwitch.
I think we should not talk specifically about vSwitch, as
another implementation of host memnic is possible. Maybe using
the term "host" is more appropriate?
> + if (idx != ACCESS_ONCE(adapter->down_idx)) {
> + /*
> + * vSwitch freed this and got false positive,
> + * need to recover the status and retry.
> + */
> + p->status = MEMNIC_PKT_ST_FREE;
> + goto retry;
> + }
> +
The patch indeed looks to improve reliability, even if it's
difficult to me to be sure that there is no other race condition.
Again, I would replace "vSwitch" by "host".
By the way, I guess the Linux code in linux/memnic_net.c should be
modified in the same way.
Regards,
Olivier
next prev parent reply other threads:[~2014-03-26 16:42 UTC|newest]
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-03-11 5:37 Hiroshi Shimamoto
2014-03-26 16:44 ` Olivier MATZ [this message]
2014-03-28 9:49 ` Hiroshi Shimamoto
2014-03-28 14:43 ` Thomas Monjalon
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