From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: "Ola Liljedahl" <Ola.Liljedahl@arm.com>,
"Stephen Hemminger" <stephen@networkplumber.org>,
"Mattias Rönnblom" <mattias.ronnblom@ericsson.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"thomas@monjalon.net" <thomas@monjalon.net>,
David Marchand <david.marchand@redhat.com>,
"onar.olsen@ericsson.com" <onar.olsen@ericsson.com>,
nd <nd@arm.com>,
"konstantin.ananyev@intel.com" <konstantin.ananyev@intel.com>,
"mb@smartsharesystems.com" <mb@smartsharesystems.com>,
nd <nd@arm.com>
Subject: RE: [PATCH v2] eal: add seqlock
Date: Sat, 2 Apr 2022 19:37:27 +0000 [thread overview]
Message-ID: <DBAPR08MB5814D8D8067D7D5338D0D76298E39@DBAPR08MB5814.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <422fc5ba-8835-777e-2a3a-6ce599963001@arm.com>
<snip>
> >> +static inline void
> >> +rte_seqlock_write_end(rte_seqlock_t *seqlock) {
> >> + uint32_t sn;
> >> +
> >> + sn = seqlock->sn + 1;
> >> +
> >> + /* synchronizes-with the load acquire in rte_seqlock_begin()
> >> */
> >> + __atomic_store_n(&seqlock->sn, sn, __ATOMIC_RELEASE);
> >> +
> >> + rte_spinlock_unlock(&seqlock->lock);
> > Atomic store is not necessary here, the atomic operation in
> > spinlock_unlock wil assure theat the seqeuence number update is
> > ordered correctly.
> Load-acquire(seqlock->sn) in rte_seqlock_begin() must be paired with
> store-release(seqlock->sn) in rte_seqlock_write_end() or there wouldn't exist
> any synchronize-with relationship. Readers don't access the spin lock so any
> writer-side updates to the spin lock don't mean anything to readers.
Agree with this assessment. The store-release in spin-lock unlock does not synchronize with the readers.
next prev parent reply other threads:[~2022-04-02 19:37 UTC|newest]
Thread overview: 104+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-22 16:10 DPDK seqlock Mattias Rönnblom
2022-03-22 16:46 ` Ananyev, Konstantin
2022-03-24 4:52 ` Honnappa Nagarahalli
2022-03-24 5:06 ` Stephen Hemminger
2022-03-24 11:34 ` Mattias Rönnblom
2022-03-25 20:24 ` [RFC] eal: add seqlock Mattias Rönnblom
2022-03-25 21:10 ` Stephen Hemminger
2022-03-26 14:57 ` Mattias Rönnblom
2022-03-27 14:49 ` Ananyev, Konstantin
2022-03-27 17:42 ` Mattias Rönnblom
2022-03-28 10:53 ` Ananyev, Konstantin
2022-03-28 14:06 ` Ola Liljedahl
2022-03-29 8:32 ` Mattias Rönnblom
2022-03-29 13:20 ` Ananyev, Konstantin
2022-03-30 10:07 ` [PATCH] " Mattias Rönnblom
2022-03-30 10:50 ` Morten Brørup
2022-03-30 11:24 ` Tyler Retzlaff
2022-03-30 11:25 ` Mattias Rönnblom
2022-03-30 14:26 ` [PATCH v2] " Mattias Rönnblom
2022-03-31 7:46 ` Mattias Rönnblom
2022-03-31 9:04 ` Ola Liljedahl
2022-03-31 9:25 ` Morten Brørup
2022-03-31 9:38 ` Ola Liljedahl
2022-03-31 10:03 ` Morten Brørup
2022-03-31 11:44 ` Ola Liljedahl
2022-03-31 11:50 ` Morten Brørup
2022-03-31 14:02 ` Mattias Rönnblom
2022-04-01 15:07 ` [PATCH v3] " Mattias Rönnblom
2022-04-02 0:21 ` Honnappa Nagarahalli
2022-04-02 11:01 ` Morten Brørup
2022-04-02 19:38 ` Honnappa Nagarahalli
2022-04-10 13:51 ` [RFC 1/3] eal: add macro to warn for unused function return values Mattias Rönnblom
2022-04-10 13:51 ` [RFC 2/3] eal: emit warning for unused trylock return value Mattias Rönnblom
2022-04-10 13:51 ` [RFC 3/3] examples/bond: fix invalid use of trylock Mattias Rönnblom
2022-04-11 1:01 ` Min Hu (Connor)
2022-04-11 14:32 ` Mattias Rönnblom
2022-04-11 11:25 ` David Marchand
2022-04-11 14:33 ` Mattias Rönnblom
2022-04-10 18:02 ` [RFC 1/3] eal: add macro to warn for unused function return values Stephen Hemminger
2022-04-10 18:50 ` Mattias Rönnblom
2022-04-11 7:17 ` Morten Brørup
2022-04-11 14:29 ` Mattias Rönnblom
2022-04-11 9:16 ` Bruce Richardson
2022-04-11 14:27 ` Mattias Rönnblom
2022-04-11 15:15 ` [PATCH " Mattias Rönnblom
2022-04-11 15:15 ` [PATCH 2/3] eal: emit warning for unused trylock return value Mattias Rönnblom
2022-04-11 15:29 ` Morten Brørup
2022-04-11 15:15 ` [PATCH 3/3] examples/bond: fix invalid use of trylock Mattias Rönnblom
2022-04-14 12:06 ` David Marchand
2022-04-11 15:25 ` [PATCH 1/3] eal: add macro to warn for unused function return values Morten Brørup
2022-04-11 18:24 ` [RFC " Tyler Retzlaff
2022-04-03 6:10 ` [PATCH v3] eal: add seqlock Mattias Rönnblom
2022-04-03 17:27 ` Honnappa Nagarahalli
2022-04-03 18:37 ` Ola Liljedahl
2022-04-04 21:56 ` Honnappa Nagarahalli
2022-04-03 6:33 ` Mattias Rönnblom
2022-04-03 17:37 ` Honnappa Nagarahalli
2022-04-08 13:45 ` Mattias Rönnblom
2022-04-02 18:15 ` Ola Liljedahl
2022-04-02 19:31 ` Honnappa Nagarahalli
2022-04-02 20:36 ` Morten Brørup
2022-04-02 22:01 ` Honnappa Nagarahalli
2022-04-03 18:11 ` Ola Liljedahl
2022-04-03 6:51 ` Mattias Rönnblom
2022-03-31 13:51 ` [PATCH v2] " Mattias Rönnblom
2022-04-02 0:54 ` Stephen Hemminger
2022-04-02 10:25 ` Morten Brørup
2022-04-02 17:43 ` Ola Liljedahl
2022-03-31 13:38 ` Mattias Rönnblom
2022-03-31 14:53 ` Ola Liljedahl
2022-04-02 0:52 ` Stephen Hemminger
2022-04-03 6:23 ` Mattias Rönnblom
2022-04-02 0:50 ` Stephen Hemminger
2022-04-02 17:54 ` Ola Liljedahl
2022-04-02 19:37 ` Honnappa Nagarahalli [this message]
2022-04-05 20:16 ` Stephen Hemminger
2022-04-08 13:50 ` Mattias Rönnblom
2022-04-08 14:24 ` [PATCH v4] " Mattias Rönnblom
2022-04-08 15:17 ` Stephen Hemminger
2022-04-08 16:24 ` Mattias Rönnblom
2022-04-08 15:19 ` Stephen Hemminger
2022-04-08 16:37 ` Mattias Rönnblom
2022-04-08 16:48 ` Mattias Rönnblom
2022-04-12 17:27 ` Ananyev, Konstantin
2022-04-28 10:28 ` David Marchand
2022-05-01 13:46 ` Mattias Rönnblom
2022-05-01 14:03 ` [PATCH v5] " Mattias Rönnblom
2022-05-01 14:22 ` Mattias Rönnblom
2022-05-02 6:47 ` David Marchand
2022-05-01 20:17 ` Stephen Hemminger
2022-05-02 4:51 ` Mattias Rönnblom
2022-05-06 1:26 ` fengchengwen
2022-05-06 1:33 ` Honnappa Nagarahalli
2022-05-06 4:17 ` fengchengwen
2022-05-06 5:19 ` Honnappa Nagarahalli
2022-05-06 7:03 ` fengchengwen
2022-05-08 11:56 ` Mattias Rönnblom
2022-05-08 12:12 ` [PATCH v6] " Mattias Rönnblom
2022-05-08 16:10 ` Stephen Hemminger
2022-05-08 19:40 ` Mattias Rönnblom
2022-05-09 3:48 ` Stephen Hemminger
2022-05-09 6:26 ` Morten Brørup
2022-05-13 6:27 ` Mattias Rönnblom
2022-03-23 12:04 ` DPDK seqlock Morten Brørup
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