From: "Tan, Jianfeng" <jianfeng.tan@intel.com>
To: "Burakov, Anatoly" <anatoly.burakov@intel.com>,
"dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v3 4/5] eal: prevent secondary process init while sending messages
Date: Wed, 28 Feb 2018 23:49:31 +0800 [thread overview]
Message-ID: <e8501f32-7d36-c52e-973e-9aa14017134c@intel.com> (raw)
In-Reply-To: <78e91c1c-2f7f-e93b-4e4b-ef1d77aa1140@intel.com>
On 2/28/2018 6:19 PM, Burakov, Anatoly wrote:
> On 28-Feb-18 1:58 AM, Tan, Jianfeng wrote:
>> Hi Anatoly,
>>
>>> -----Original Message-----
>>> From: Burakov, Anatoly
>>> Sent: Tuesday, February 27, 2018 10:36 PM
>>> To: dev@dpdk.org
>>> Cc: Tan, Jianfeng
>>> Subject: [PATCH v3 4/5] eal: prevent secondary process init while
>>> sending
>>> messages
>>>
>>> Currently, it is possible to spin up a secondary process while
>>> either sendmsg or request is in progress. Fix this by adding
>>> directory locks during init, sendmsg and requests.
>>
>> Could you give a more detailed example for this issue?
>>
>> And why locking the directory can help?
>>
>> Thanks,
>> Jianfeng
>>
>
> Consider this. You start a request. Since sending this out takes
> non-zero amount of time, and you're waiting for process to reply each
> time you send a message, there's a non-zero chance where contents of
> /var/run may change and another socket file may appear that wasn't
> there when we started sending out those messages.
OK, I see the issue now. When primary broadcasts a request and another
secondary joins, then if that request will be delivered to the new
secondary, it's an undefined behavior.
>
> This is simply making sending requests atomic, if you will. Honestly,
> i can't think of a situation where this might be a problem, but it
> just doesn't feel right, so i fixed it :)
>
The way seems a little overkill to me. But I did not find a better way :-)
Thanks,
Jianfeng
next prev parent reply other threads:[~2018-02-28 15:49 UTC|newest]
Thread overview: 57+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-02-22 18:21 [dpdk-dev] [PATCH 1/3] eal: add internal flag indicating init has completed Anatoly Burakov
2018-02-22 18:21 ` [dpdk-dev] [PATCH 2/3] eal: don't process IPC messages before init finished Anatoly Burakov
2018-02-22 18:21 ` [dpdk-dev] [PATCH 3/3] eal: use locks to determine if secondary process is active Anatoly Burakov
2018-03-02 15:14 ` [dpdk-dev] [PATCH v4 1/5] eal: add internal flag indicating init has completed Anatoly Burakov
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 0/6] Improvements for DPDK IPC Anatoly Burakov
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 " Anatoly Burakov
2018-03-21 17:43 ` Thomas Monjalon
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 1/6] eal: add internal flag indicating init has completed Anatoly Burakov
2018-03-13 20:59 ` Bruce Richardson
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 2/6] eal: abstract away IPC socket path generation Anatoly Burakov
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 3/6] eal: don't hardcode socket filter value in IPC Anatoly Burakov
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 4/6] eal: lock IPC directory on init and send Anatoly Burakov
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 5/6] eal: simplify IPC sync request timeout code Anatoly Burakov
2018-03-13 17:42 ` [dpdk-dev] [PATCH v6 6/6] eal: ignore messages until init is complete Anatoly Burakov
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 1/6] eal: add internal flag indicating init has completed Anatoly Burakov
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 2/6] eal: abstract away IPC socket path generation Anatoly Burakov
2018-03-11 9:02 ` Tan, Jianfeng
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 3/6] eal: don't hardcode socket filter value in IPC Anatoly Burakov
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 4/6] eal: lock IPC directory on init and send Anatoly Burakov
2018-03-11 9:14 ` Tan, Jianfeng
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 5/6] eal: simplify IPC sync request timeout code Anatoly Burakov
2018-03-11 9:25 ` Tan, Jianfeng
2018-03-07 16:56 ` [dpdk-dev] [PATCH v5 6/6] eal: ignore messages until init is complete Anatoly Burakov
2018-03-12 1:42 ` Tan, Jianfeng
2018-03-12 8:58 ` Burakov, Anatoly
2018-03-02 15:14 ` [dpdk-dev] [PATCH v4 2/5] eal: use file to check if secondary process is ready Anatoly Burakov
2018-03-06 11:03 ` Burakov, Anatoly
2018-03-02 15:14 ` [dpdk-dev] [PATCH v4 3/5] eal: prevent secondary process init while sending messages Anatoly Burakov
2018-03-02 15:14 ` [dpdk-dev] [PATCH v4 4/5] eal: don't hardcode socket filter value in IPC Anatoly Burakov
2018-03-02 15:14 ` [dpdk-dev] [PATCH v4 5/5] eal: simplify IPC sync request timeout code Anatoly Burakov
2018-02-22 18:32 ` [dpdk-dev] [PATCH 1/3] eal: add internal flag indicating init has completed Burakov, Anatoly
2018-02-27 13:23 ` [dpdk-dev] [PATCH v2 1/5] " Anatoly Burakov
2018-02-27 14:35 ` [dpdk-dev] [PATCH v3 " Anatoly Burakov
2018-02-28 2:12 ` Tan, Jianfeng
2018-02-28 9:43 ` Burakov, Anatoly
2018-02-27 14:35 ` [dpdk-dev] [PATCH v3 2/5] eal: don't process IPC messages before init finished Anatoly Burakov
2018-02-28 1:09 ` Tan, Jianfeng
2018-02-28 9:45 ` Burakov, Anatoly
2018-02-28 4:00 ` Wiles, Keith
2018-02-28 9:47 ` Burakov, Anatoly
2018-02-27 14:35 ` [dpdk-dev] [PATCH v3 3/5] eal: use locks to determine if secondary process is active Anatoly Burakov
2018-02-28 1:26 ` Tan, Jianfeng
2018-02-28 10:15 ` Burakov, Anatoly
2018-02-28 4:17 ` Wiles, Keith
2018-02-28 10:17 ` Burakov, Anatoly
2018-02-27 14:35 ` [dpdk-dev] [PATCH v3 4/5] eal: prevent secondary process init while sending messages Anatoly Burakov
2018-02-28 1:58 ` Tan, Jianfeng
2018-02-28 10:19 ` Burakov, Anatoly
2018-02-28 15:49 ` Tan, Jianfeng [this message]
2018-02-27 14:35 ` [dpdk-dev] [PATCH v3 5/5] eal: don't hardcode socket filter value in IPC Anatoly Burakov
2018-02-28 1:52 ` Tan, Jianfeng
2018-02-28 10:21 ` Burakov, Anatoly
2018-02-28 15:01 ` Tan, Jianfeng
2018-02-27 13:23 ` [dpdk-dev] [PATCH v2 2/5] eal: don't process IPC messages before init finished Anatoly Burakov
2018-02-27 13:23 ` [dpdk-dev] [PATCH v2 3/5] eal: use locks to determine if secondary process is active Anatoly Burakov
2018-02-27 13:23 ` [dpdk-dev] [PATCH v2 4/5] eal: prevent secondary process init while sending messages Anatoly Burakov
2018-02-27 13:23 ` [dpdk-dev] [PATCH v2 5/5] eal: don't hardcode socket filter value in IPC Anatoly Burakov
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