From: Jerin Jacob <jerin.jacob@caviumnetworks.com>
To: Gavin Hu <gavin.hu@arm.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"Honnappa.Nagarahalli@arm.com" <Honnappa.Nagarahalli@arm.com>,
"steve.capper@arm.com" <steve.capper@arm.com>,
"Ola.Liljedahl@arm.com" <Ola.Liljedahl@arm.com>,
"nd@arm.com" <nd@arm.com>, "stable@dpdk.org" <stable@dpdk.org>,
"jia.he@hxt-semitech.com" <jia.he@hxt-semitech.com>
Subject: Re: [dpdk-stable] [PATCH v4 2/4] ring: read tail using atomic load
Date: Thu, 20 Sep 2018 06:41:26 +0000 [thread overview]
Message-ID: <20180920064117.GC2283@jerin> (raw)
In-Reply-To: <1537171879-64390-2-git-send-email-gavin.hu@arm.com>
-----Original Message-----
> Date: Mon, 17 Sep 2018 16:11:17 +0800
> From: Gavin Hu <gavin.hu@arm.com>
> To: dev@dpdk.org
> CC: gavin.hu@arm.com, Honnappa.Nagarahalli@arm.com, steve.capper@arm.com,
> Ola.Liljedahl@arm.com, jerin.jacob@caviumnetworks.com, nd@arm.com,
> stable@dpdk.org
> Subject: [PATCH v4 2/4] ring: read tail using atomic load
> X-Mailer: git-send-email 2.7.4
>
>
> In update_tail, read ht->tail using __atomic_load.Although the
> compiler currently seems to be doing the right thing even without
> _atomic_load, we don't want to give the compiler freedom to optimise
> what should be an atomic load, it should not be arbitarily moved
> around.
>
> Fixes: 39368ebfc6 ("ring: introduce C11 memory model barrier option")
> Cc: stable@dpdk.org
+ Jia He <jia.he@hxt-semitech.com>
>
> Signed-off-by: Gavin Hu <gavin.hu@arm.com>
> Reviewed-by: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
> Reviewed-by: Steve Capper <steve.capper@arm.com>
> Reviewed-by: Ola Liljedahl <Ola.Liljedahl@arm.com>
> ---
> lib/librte_ring/rte_ring_c11_mem.h | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/lib/librte_ring/rte_ring_c11_mem.h b/lib/librte_ring/rte_ring_c11_mem.h
> index 94df3c4..234fea0 100644
> --- a/lib/librte_ring/rte_ring_c11_mem.h
> +++ b/lib/librte_ring/rte_ring_c11_mem.h
> @@ -21,7 +21,8 @@ update_tail(struct rte_ring_headtail *ht, uint32_t old_val, uint32_t new_val,
> * we need to wait for them to complete
> */
> if (!single)
> - while (unlikely(ht->tail != old_val))
> + while (unlikely(old_val != __atomic_load_n(&ht->tail,
> + __ATOMIC_RELAXED)))
> rte_pause();
>
> __atomic_store_n(&ht->tail, new_val, __ATOMIC_RELEASE);
> --
> 2.7.4
>
next prev parent reply other threads:[~2018-09-20 6:41 UTC|newest]
Thread overview: 125+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-08-06 1:18 [dpdk-stable] [PATCH] ring: fix c11 memory ordering issue Gavin Hu
2018-08-06 9:19 ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2018-08-08 1:39 ` Gavin Hu
2018-08-07 3:19 ` [dpdk-stable] [PATCH v2] " Gavin Hu
2018-08-07 5:56 ` He, Jia
2018-08-07 7:56 ` Gavin Hu
2018-08-08 3:07 ` Jerin Jacob
2018-08-08 7:23 ` Thomas Monjalon
[not found] ` <20180917074735.28161-1-gavin.hu@arm.com>
2018-09-17 7:47 ` [dpdk-stable] [PATCH v3 3/3] doc: add cross compile part for sample applications Gavin Hu
2018-09-17 9:48 ` Jerin Jacob
2018-09-17 10:28 ` Gavin Hu (Arm Technology China)
2018-09-17 10:34 ` Jerin Jacob
2018-09-17 10:55 ` Gavin Hu (Arm Technology China)
2018-09-17 10:49 ` [dpdk-stable] [PATCH v4] " Gavin Hu
2018-09-17 10:53 ` [dpdk-stable] [PATCH v5] " Gavin Hu
2018-09-18 11:00 ` Jerin Jacob
2018-09-19 0:33 ` [dpdk-stable] [PATCH v6] " Gavin Hu
2018-09-17 8:11 ` [dpdk-stable] [PATCH v4 1/4] bus/fslmc: fix undefined reference of memsegs Gavin Hu
2018-09-17 8:11 ` [dpdk-stable] [PATCH v4 2/4] ring: read tail using atomic load Gavin Hu
2018-09-20 6:41 ` Jerin Jacob [this message]
2018-09-25 9:26 ` Gavin Hu (Arm Technology China)
2018-09-17 8:11 ` [dpdk-stable] [PATCH v4 3/4] ring: synchronize the load and store of the tail Gavin Hu
2018-09-17 8:11 ` [dpdk-stable] [PATCH v4 4/4] ring: move the atomic load of head above the loop Gavin Hu
2018-10-27 14:21 ` Thomas Monjalon
2018-09-17 8:17 ` [dpdk-stable] [PATCH v3 1/3] ring: read tail using atomic load Gavin Hu
2018-09-17 8:17 ` [dpdk-stable] [PATCH v3 2/3] ring: synchronize the load and store of the tail Gavin Hu
2018-09-26 9:29 ` Gavin Hu (Arm Technology China)
2018-09-26 9:59 ` Justin He
2018-09-29 10:57 ` Jerin Jacob
2018-10-17 6:29 ` [dpdk-stable] [PATCH 1/2] " Gavin Hu
2018-10-17 6:29 ` [dpdk-stable] [PATCH 2/2] ring: move the atomic load of head above the loop Gavin Hu
2018-10-17 6:35 ` [dpdk-stable] [PATCH 1/2] ring: synchronize the load and store of the tail Gavin Hu (Arm Technology China)
2018-10-27 14:39 ` [dpdk-stable] [dpdk-dev] " Thomas Monjalon
2018-10-27 15:00 ` Jerin Jacob
2018-10-27 15:13 ` Thomas Monjalon
2018-10-27 15:34 ` Jerin Jacob
2018-10-27 15:48 ` Thomas Monjalon
2018-10-29 2:51 ` Gavin Hu (Arm Technology China)
2018-10-29 2:57 ` Gavin Hu (Arm Technology China)
2018-10-29 10:16 ` Jerin Jacob
2018-10-29 10:47 ` Thomas Monjalon
2018-10-29 11:10 ` Jerin Jacob
2018-11-03 20:12 ` Mattias Rönnblom
2018-11-05 21:51 ` Honnappa Nagarahalli
2018-11-06 11:03 ` Mattias Rönnblom
[not found] ` <1540955698-209159-1-git-send-email-gavin.hu@arm.com>
2018-10-31 3:14 ` [dpdk-stable] [PATCH v2 " Gavin Hu
2018-10-31 3:14 ` [dpdk-stable] [PATCH v2 2/2] ring: move the atomic load of head above the loop Gavin Hu
2018-10-31 3:35 ` [dpdk-stable] [PATCH v2 1/2] ring: synchronize the load and store of the tail Gavin Hu
2018-10-31 3:35 ` [dpdk-stable] [PATCH v2 2/2] ring: move the atomic load of head above the loop Gavin Hu
2018-10-31 9:36 ` Thomas Monjalon
2018-10-31 10:27 ` Gavin Hu (Arm Technology China)
2018-09-17 8:17 ` [dpdk-stable] [PATCH v3 3/3] " Gavin Hu
2018-09-26 9:29 ` Gavin Hu (Arm Technology China)
2018-09-26 10:06 ` Justin He
2018-09-29 7:19 ` [dpdk-stable] [dpdk-dev] " Stephen Hemminger
2018-09-29 10:59 ` [dpdk-stable] " Jerin Jacob
2018-09-26 9:29 ` [dpdk-stable] [PATCH v3 1/3] ring: read tail using atomic load Gavin Hu (Arm Technology China)
2018-09-26 10:09 ` Justin He
2018-09-29 10:48 ` Jerin Jacob
2018-10-05 0:47 ` Gavin Hu (Arm Technology China)
2018-10-05 8:21 ` Ananyev, Konstantin
2018-10-05 11:15 ` Ola Liljedahl
2018-10-05 11:36 ` Ola Liljedahl
2018-10-05 13:44 ` Ananyev, Konstantin
2018-10-05 14:21 ` Ola Liljedahl
2018-10-05 15:11 ` Honnappa Nagarahalli
2018-10-05 17:07 ` Jerin Jacob
2018-10-05 18:05 ` Ola Liljedahl
2018-10-05 20:06 ` Honnappa Nagarahalli
2018-10-05 20:17 ` Ola Liljedahl
2018-10-05 20:29 ` Honnappa Nagarahalli
2018-10-05 20:34 ` Ola Liljedahl
2018-10-06 7:41 ` Jerin Jacob
2018-10-06 19:44 ` Ola Liljedahl
2018-10-06 19:59 ` Ola Liljedahl
2018-10-07 4:02 ` Jerin Jacob
2018-10-07 20:11 ` Ola Liljedahl
2018-10-07 20:44 ` Ola Liljedahl
2018-10-08 6:06 ` Jerin Jacob
2018-10-08 9:22 ` Ola Liljedahl
2018-10-08 10:00 ` Jerin Jacob
2018-10-08 10:25 ` Ola Liljedahl
2018-10-08 10:33 ` Gavin Hu (Arm Technology China)
2018-10-08 10:39 ` Ola Liljedahl
2018-10-08 10:41 ` Gavin Hu (Arm Technology China)
2018-10-08 10:49 ` Jerin Jacob
2018-10-10 6:28 ` Gavin Hu (Arm Technology China)
2018-10-10 19:26 ` Honnappa Nagarahalli
2018-10-08 10:46 ` Jerin Jacob
2018-10-08 11:21 ` Ola Liljedahl
2018-10-08 11:50 ` Jerin Jacob
2018-10-08 11:59 ` Ola Liljedahl
2018-10-08 12:05 ` Jerin Jacob
2018-10-08 12:20 ` [dpdk-stable] [dpdk-dev] " Jerin Jacob
2018-10-08 12:30 ` Ola Liljedahl
2018-10-09 8:53 ` Olivier Matz
2018-10-09 3:16 ` [dpdk-stable] " Honnappa Nagarahalli
2018-10-08 14:43 ` [dpdk-stable] [dpdk-dev] " Bruce Richardson
2018-10-08 14:46 ` Ola Liljedahl
2018-10-08 15:45 ` Ola Liljedahl
2018-10-08 5:27 ` [dpdk-stable] " Honnappa Nagarahalli
2018-10-08 10:01 ` Ola Liljedahl
2018-10-27 14:17 ` Thomas Monjalon
[not found] <1541157688-40012-1-git-send-email-gavin.hu@arm.com>
[not found] ` <1541066031-29125-1-git-send-email-gavin.hu@arm.com>
[not found] ` <1540981587-88590-1-git-send-email-gavin.hu@arm.com>
[not found] ` <1540956945-211373-1-git-send-email-gavin.hu@arm.com>
2018-10-31 10:26 ` [dpdk-stable] [PATCH v3 1/2] ring: synchronize the load and store of the tail Gavin Hu
2018-10-31 22:07 ` [dpdk-stable] [dpdk-dev] " Stephen Hemminger
2018-11-01 9:56 ` Gavin Hu (Arm Technology China)
2018-10-31 10:26 ` [dpdk-stable] [PATCH v3 2/2] ring: move the atomic load of head above the loop Gavin Hu
2018-11-01 9:53 ` [dpdk-stable] [PATCH v4 1/2] ring: synchronize the load and store of the tail Gavin Hu
2018-11-01 9:53 ` [dpdk-stable] [PATCH v4 2/2] ring: move the atomic load of head above the loop Gavin Hu
2018-11-01 17:26 ` Stephen Hemminger
2018-11-02 0:53 ` Gavin Hu (Arm Technology China)
2018-11-02 4:30 ` Honnappa Nagarahalli
2018-11-02 7:15 ` Gavin Hu (Arm Technology China)
2018-11-02 9:36 ` Thomas Monjalon
2018-11-02 11:23 ` Gavin Hu (Arm Technology China)
2018-11-02 11:21 ` [dpdk-stable] [PATCH v5 1/2] ring: synchronize the load and store of the tail Gavin Hu
2018-11-05 9:30 ` Olivier Matz
2018-11-02 11:21 ` [dpdk-stable] [PATCH v5 2/2] ring: move the atomic load of head above the loop Gavin Hu
2018-11-02 11:43 ` Bruce Richardson
2018-11-03 1:19 ` Gavin Hu (Arm Technology China)
2018-11-03 9:34 ` Honnappa Nagarahalli
2018-11-05 13:17 ` Thomas Monjalon
2018-11-05 13:41 ` Jerin Jacob
2018-11-05 9:44 ` Olivier Matz
2018-11-05 13:36 ` Thomas Monjalon
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=20180920064117.GC2283@jerin \
--to=jerin.jacob@caviumnetworks.com \
--cc=Honnappa.Nagarahalli@arm.com \
--cc=Ola.Liljedahl@arm.com \
--cc=dev@dpdk.org \
--cc=gavin.hu@arm.com \
--cc=jia.he@hxt-semitech.com \
--cc=nd@arm.com \
--cc=stable@dpdk.org \
--cc=steve.capper@arm.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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).