All of lore.kernel.org
 help / color / mirror / Atom feed
From: Olivier Matz <olivier.matz@6wind.com>
To: Lazaros Koromilas <l@nofutznetworks.com>, dev@dpdk.org
Subject: Re: [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 [PATCH v2] ring: check for zero objects mc dequeue / mp enqueue 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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=56EFE7CE.9010804@6wind.com \
    --to=olivier.matz@6wind.com \
    --cc=dev@dpdk.org \
    --cc=l@nofutznetworks.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.