From: Honnappa Nagarahalli <Honnappa.Nagarahalli@arm.com>
To: "Wang, Yipeng1" <yipeng1.wang@intel.com>,
"Richardson, Bruce" <bruce.richardson@intel.com>,
"De Lara Guarch, Pablo" <pablo.de.lara.guarch@intel.com>
Cc: "dev@dpdk.org" <dev@dpdk.org>,
"Gavin Hu (Arm Technology China)" <Gavin.Hu@arm.com>,
Steve Capper <Steve.Capper@arm.com>,
Ola Liljedahl <Ola.Liljedahl@arm.com>, nd <nd@arm.com>,
"Gobriel, Sameh" <sameh.gobriel@intel.com>
Subject: Re: [dpdk-dev] [PATCH 3/4] hash: fix rw concurrency while moving keys
Date: Wed, 3 Oct 2018 17:39:13 +0000 [thread overview]
Message-ID: <AM6PR08MB3672B8F0700ADF4E950CB18998E90@AM6PR08MB3672.eurprd08.prod.outlook.com> (raw)
In-Reply-To: <D2C4A16CA39F7F4E8E384D204491D7A6614EB0E3@FMSMSX151.amr.corp.intel.com>
> >-----Original Message-----
> >[Wang, Yipeng] I was thinking about another corner case and wondering
> >if the version counter needs to be done on key deletion as well.
> >For example, a reader reads out the index and falsely matches a
> >signature, before it reads out the data and the key, the key-data pair
> >got deleted, removed, and recycled by another writer thread. This
> >writer partially overwrote the key (because key store is too large to be
> atomic).
> >Now, the reader begins to compare the key, and accidentally matches the
> >key (because the key is partially written and accidentally matches),
> >will The reader read the wrong data out (which should have been a lookup
> miss)?
> >
> [Wang, Yipeng] As a second thought after reading your slides, I think the
> scenario I described above should be handled by the upper level application
> using RCU-like mechanisms to recycle key-data only after the grace period.
> So I think it is OK. Please ignore my last comment.
>
> But if convenient, please add more comment in the API doc and in user
> guide as well just in case users might not understand the restriction.
>
Agree, it needs careful documentation. I plan to change the documentation after the patch is completed.
> Thanks
> Yipeng
next prev parent reply other threads:[~2018-10-03 17:39 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-09-06 17:12 [dpdk-dev] [PATCH 0/4] Address reader-writer concurrency in rte_hash Honnappa Nagarahalli
2018-09-06 17:12 ` [dpdk-dev] [PATCH 1/4] hash: correct key store element alignment Honnappa Nagarahalli
2018-09-27 23:58 ` Wang, Yipeng1
2018-09-06 17:12 ` [dpdk-dev] [PATCH 2/4] hash: add memory ordering to avoid race conditions Honnappa Nagarahalli
2018-09-28 0:43 ` Wang, Yipeng1
2018-09-30 22:20 ` Honnappa Nagarahalli
2018-10-01 22:41 ` Wang, Yipeng1
2018-10-01 10:42 ` Ola Liljedahl
2018-10-02 1:52 ` Wang, Yipeng1
2018-09-06 17:12 ` [dpdk-dev] [PATCH 3/4] hash: fix rw concurrency while moving keys Honnappa Nagarahalli
2018-09-28 1:00 ` Wang, Yipeng1
2018-09-28 8:26 ` Bruce Richardson
2018-09-28 8:55 ` Van Haaren, Harry
2018-09-30 22:33 ` Honnappa Nagarahalli
2018-10-02 13:17 ` Van Haaren, Harry
2018-10-02 23:58 ` Wang, Yipeng1
2018-10-03 17:32 ` Honnappa Nagarahalli
2018-10-03 17:56 ` Wang, Yipeng1
2018-10-03 23:05 ` Ola Liljedahl
2018-10-04 3:32 ` Honnappa Nagarahalli
2018-10-04 3:54 ` Honnappa Nagarahalli
2018-10-04 19:16 ` Wang, Yipeng1
2018-09-30 23:05 ` Honnappa Nagarahalli
2018-10-01 22:56 ` Wang, Yipeng1
2018-10-03 0:16 ` Wang, Yipeng1
2018-10-03 17:39 ` Honnappa Nagarahalli [this message]
2018-09-06 17:12 ` [dpdk-dev] [PATCH 4/4] hash: enable lock-free reader-writer concurrency Honnappa Nagarahalli
2018-09-28 1:33 ` Wang, Yipeng1
2018-10-01 4:11 ` Honnappa Nagarahalli
2018-10-01 23:54 ` Wang, Yipeng1
2018-10-11 5:24 ` Honnappa Nagarahalli
2018-09-14 21:18 ` [dpdk-dev] [PATCH 0/4] Address reader-writer concurrency in rte_hash Honnappa Nagarahalli
2018-09-26 14:36 ` Honnappa Nagarahalli
2018-09-27 23:45 ` Wang, Yipeng1
2018-09-28 21:11 ` Honnappa Nagarahalli
2018-10-02 0:30 ` Wang, Yipeng1
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