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From: Olivier Matz <olivier.matz@6wind.com>
To: Lazaros Koromilas <l@nofutznetworks.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2] ring: check for zero objects mc dequeue / mp enqueue
Date: Mon, 21 Mar 2016 13:23:42 +0100	[thread overview]
Message-ID: <56EFE7CE.9010804@6wind.com> (raw)
In-Reply-To: <1458229783-15547-1-git-send-email-l@nofutznetworks.com>

Hi,

On 03/17/2016 04:49 PM, Lazaros Koromilas wrote:
> Issuing a zero objects dequeue with a single consumer has no effect.
> Doing so with multiple consumers, can get more than one thread to succeed
> the compare-and-set operation and observe starvation or even deadlock in
> the while loop that checks for preceding dequeues.  The problematic piece
> of code when n = 0:
> 
>     cons_next = cons_head + n;
>     success = rte_atomic32_cmpset(&r->cons.head, cons_head, cons_next);
> 
> The same is possible on the enqueue path.
> 
> Signed-off-by: Lazaros Koromilas <l@nofutznetworks.com>

Acked-by: Olivier Matz <olivier.matz@6wind.com>

  parent reply	other threads:[~2016-03-21 12:23 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-17 15:49 Lazaros Koromilas
2016-03-17 16:09 ` Mauricio Vásquez
2016-03-18 10:18   ` Bruce Richardson
2016-03-18 10:27     ` Olivier Matz
2016-03-18 10:35       ` Bruce Richardson
2016-03-18 10:35       ` Thomas Monjalon
2016-03-18 12:47         ` Mauricio Vásquez
2016-03-18 14:16           ` Bruce Richardson
2016-03-21 17:47             ` Xie, Huawei
2016-03-22 10:13               ` Bruce Richardson
2016-03-22 14:38                 ` Xie, Huawei
2016-03-21 12:23 ` Olivier Matz [this message]
2016-03-22 16:49   ` Thomas Monjalon
2016-03-25 11:15 ` Olivier Matz
2016-03-28 15:48   ` Lazaros Koromilas
2016-03-29  8:54     ` Bruce Richardson
2016-03-29 15:29       ` Olivier MATZ
2016-03-29 16:04         ` Bruce Richardson
2016-03-29 17:35           ` Lazaros Koromilas

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