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From: Neil Horman <nhorman@tuxdriver.com>
To: Matan Azrad <matan@mellanox.com>
Cc: "Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	Thomas Monjalon <thomas@monjalon.net>,
	Gaetan Rivet <gaetan.rivet@6wind.com>,
	"Wu, Jingjing" <jingjing.wu@intel.com>,
	"dev@dpdk.org" <dev@dpdk.org>,
	"Richardson, Bruce" <bruce.richardson@intel.com>
Subject: Re: [dpdk-dev] [PATCH v2 2/6] ethdev: add port ownership
Date: Fri, 19 Jan 2018 08:52:49 -0500	[thread overview]
Message-ID: <20180119135249.GC5342@hmswarspite.think-freely.org> (raw)
In-Reply-To: <AM6PR0502MB379755BBA6DB19DD26AB2523D2EF0@AM6PR0502MB3797.eurprd05.prod.outlook.com>

On Fri, Jan 19, 2018 at 07:14:17AM +0000, Matan Azrad wrote:
> 
> Hi Neil
> From: Neil Horman, Friday, January 19, 2018 3:41 AM
> > On Thu, Jan 18, 2018 at 08:21:34PM +0000, Matan Azrad wrote:
> > > Hi Neil.
> > >
> > > From: Neil Horman, Thursday, January 18, 2018 8:42 PM
> 
> <snip>
> > > 1. What exactly do you want to improve?(in details) 2. Which API
> > > specifically do you want to change(\ part of code)?
> > > 3. What is the missing in current code(you can answer it in V3 I sent if you
> > want) which should be fixed?
> > >
> > >
> > > <snip> sorry for that, I think it is not relevant continue discussion if we are
> > not fully understand each other. So let's start from the beginning "with good
> > order :)" by answering the above questions.
> > 
> > 
> > Sure, this seems like a reasonable way to level set.
> > 
> > I mentioned in another thread that perhaps some of my issue here is
> > perception regarding what is meant by ownership.  When I think of an
> > ownership api I think primarily of mutual exclusion (that is to say,
> > enforcement of a single execution context having access to a resource at any
> > given time.  In my mind the simplest form of ownership is a spinlock or a
> > mutex.  A single execution context either does or does not hold the resource
> > at any one time.  Those contexts that attempt to gain excusive access to the
> > resource call an api that (depending on
> > implementation) either block continued execution of that thread until
> > exclusive access to the resource can be granted, or returns immediately with
> > a success or error indicator to let the caller know if access is granted.
> > 
> > If I were to codify this port ownership api in pseudo code it would look
> > something like this:
> > 
> > struct rte_eth_dev {
> > 
> > 	< eth dev bits >
> > 	rte_spinlock_t owner_lock;
> > 	bool locked;
> > 	pid_t owner_pid;
> > }
> > 
> > 
> > bool rte_port_claim_ownership(struct rte_eth_dev *dev) {
> > 	bool ret = false;
> > 
> > 	spin_lock(dev->owner_lock);
> > 	if (dev->locked)
> > 		goto out;
> > 	dev->locked = true;
> > 	dev->owner_pid = getpid();
> > 	ret = true;
> > out:
> > 	spin_unlock(dev->lock)
> > 	return ret;
> > }
> > 
> > 
> > bool rte_port_release_ownership(rte_eth_dev *dev) {
> > 
> > 	boot ret = false;
> > 	spin_lock(dev->owner_lock);
> > 	if (!dev->locked)
> > 		goto out;
> > 	if (dev->owner_pid != getpid())
> > 		goto out;
> > 	dev->locked = false;
> > 	dev_owner_pid = 0;
> > 	ret = true;
> > out:
> > 	spin_unlock(dev->owner_lock)
> > 	return ret;
> > }
> > 
> > bool rte_port_is_owned_by(struct rte_eth_dev *dev, pid_t pid) {
> > 	bool ret = false;
> > 
> > 	spin_lock(dev->owner_lock);
> > 	if (pid)
> > 		ret = (dev->locked && (pid == dev->owner_pid));
> > 	else
> > 		ret = dev->locked;
> > 	spin_unlock(dev->owner_lock);
> > 	return ret;
> > }
> > 
> > The idea here is that lock state is isolated from ownership information.  Any
> > context has the opportunity to lock the resource (in this case the eth port)
> > despite its ownership object.
> > 
> > In comparison, your api, which is in may ways simmilar, separates the
> > creation of ownership objects to a separate api call, and that ownership
> > information embodies state that is integral to the ability to get exclusive
> > access to the resource.  I.E. if thread A calls your owner_new call, and then
> > thread B calls owner_new, thread A will never be able to get access to any
> > port unless it calls owner_new again.
> > 
> > Does that help clarify my position?
> 
> Now I fully understand you, thanks for your patience.
> 
> So, you are missing here one of the main ideas of my port ownership intention.
> There are options for X>1 different uncoordinated owners running in the same thread.
> 
> For example:
> 1. Think about Testpmd control commands that call to failsafe port devop which call to its sub-devices devops, while tespmd is different owner(controlling failsafe-port) and failsafe is a different owner(controlling all its sub-devices ports), There are both run control commands in the same thread and there are uncoordinated!
>  2. Interrupt callbacks that anyone can register to them and all will run by the DPDK host thread. 
> 
> So, no any optional  owner becomes an owner, it depends in the specific implementation.
> 
> So if some "part of code" wants to manage a port exclusively and wants to take ownership of it to prevent other "part of code" to use this port :
> 1. Take ownership.
> 2. It should ask itself: Am I run in different threads\processes? If yes, it should synchronize its port management. 
> 3. Release ownership in the end.
> 
> Remember that may be different "part of code"s running in the same thread\threads\process\processes.
> 
Apologies for not responding in full here, but in the interests of
de-duplication, I'm providing a larger response to the above higher up in the
the thread (the branch in which Bruce commented).

Best
Neil

> Thanks, Matan.
> > 
> > Regards
> > Neil
> > 
> > }
> 

  parent reply	other threads:[~2018-01-19 13:53 UTC|newest]

Thread overview: 212+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-28 11:57 [dpdk-dev] [PATCH 0/5] ethdev: Port ownership Matan Azrad
2017-11-28 11:57 ` [dpdk-dev] [PATCH 1/5] ethdev: free a port by a dedicated API Matan Azrad
2017-11-28 11:57 ` [dpdk-dev] [PATCH 2/5] ethdev: add port ownership Matan Azrad
2017-11-30 12:36   ` Neil Horman
2017-11-30 13:24     ` Gaëtan Rivet
2017-11-30 14:30       ` Matan Azrad
2017-11-30 15:09         ` Gaëtan Rivet
2017-11-30 15:43           ` Matan Azrad
2017-12-01 12:09       ` Neil Horman
2017-12-03  8:04         ` Matan Azrad
2017-12-03 11:10           ` Ananyev, Konstantin
2017-12-03 13:46             ` Matan Azrad
2017-12-04 16:01               ` Neil Horman
2017-12-04 18:10                 ` Matan Azrad
2017-12-04 22:30                   ` Neil Horman
2017-12-05  6:08                     ` Matan Azrad
2017-12-05 10:05                       ` Bruce Richardson
2017-12-08 11:35                         ` Thomas Monjalon
2017-12-08 12:31                           ` Neil Horman
2017-12-21 17:06                             ` Thomas Monjalon
2017-12-21 17:43                               ` Neil Horman
2017-12-21 19:37                                 ` Matan Azrad
2017-12-21 20:14                                   ` Neil Horman
2017-12-21 21:57                                     ` Matan Azrad
2017-12-22 14:26                                       ` Neil Horman
2017-12-23 22:36                                         ` Matan Azrad
2017-12-29 16:56                                           ` Neil Horman
2017-12-05 19:26                       ` Neil Horman
2017-12-08 11:06                         ` Thomas Monjalon
2017-12-05 11:12               ` Ananyev, Konstantin
2017-12-05 11:44                 ` Ananyev, Konstantin
2017-12-05 11:53                   ` Thomas Monjalon
2017-12-05 14:56                     ` Bruce Richardson
2017-12-05 14:57                     ` Ananyev, Konstantin
2017-12-05 11:47                 ` Thomas Monjalon
2017-12-05 15:13                   ` Ananyev, Konstantin
2017-12-05 15:49                     ` Thomas Monjalon
2017-11-28 11:57 ` [dpdk-dev] [PATCH 3/5] net/failsafe: free an eth port by a dedicated API Matan Azrad
2017-11-28 11:58 ` [dpdk-dev] [PATCH 4/5] net/failsafe: use ownership mechanism to own ports Matan Azrad
2017-11-28 11:58 ` [dpdk-dev] [PATCH 5/5] app/testpmd: adjust ethdev port ownership Matan Azrad
2018-01-07  9:45 ` [dpdk-dev] [PATCH v2 0/6] ethdev: " Matan Azrad
2018-01-07  9:45   ` [dpdk-dev] [PATCH v2 1/6] ethdev: fix port data reset timing Matan Azrad
2018-01-07  9:45   ` [dpdk-dev] [PATCH v2 2/6] ethdev: add port ownership Matan Azrad
2018-01-10 13:36     ` Ananyev, Konstantin
2018-01-10 16:58       ` Matan Azrad
2018-01-11 12:40         ` Ananyev, Konstantin
2018-01-11 14:51           ` Matan Azrad
2018-01-12  0:02             ` Ananyev, Konstantin
2018-01-12  7:24               ` Matan Azrad
2018-01-15 11:45                 ` Ananyev, Konstantin
2018-01-15 13:09                   ` Matan Azrad
2018-01-15 18:43                     ` Ananyev, Konstantin
2018-01-16  8:04                       ` Matan Azrad
2018-01-16 19:11                         ` Ananyev, Konstantin
2018-01-16 20:32                           ` Matan Azrad
2018-01-17 11:24                             ` Ananyev, Konstantin
2018-01-17 12:05                               ` Matan Azrad
2018-01-17 12:54                                 ` Ananyev, Konstantin
2018-01-17 13:10                                   ` Matan Azrad
2018-01-17 16:52                                     ` Ananyev, Konstantin
2018-01-17 18:02                                       ` Matan Azrad
2018-01-17 20:34                                       ` Matan Azrad
2018-01-18 14:17                                         ` Ananyev, Konstantin
2018-01-18 14:26                                           ` Matan Azrad
2018-01-18 14:41                                             ` Ananyev, Konstantin
2018-01-18 14:45                                               ` Matan Azrad
2018-01-18 14:51                                                 ` Ananyev, Konstantin
2018-01-18 15:00                                                   ` Matan Azrad
2018-01-17 14:00                                 ` Neil Horman
2018-01-17 17:01                                   ` Ananyev, Konstantin
2018-01-18 13:10                                     ` Neil Horman
2018-01-18 14:00                                       ` Matan Azrad
2018-01-18 16:54                                         ` Neil Horman
2018-01-18 17:20                                           ` Matan Azrad
2018-01-18 18:41                                             ` Neil Horman
2018-01-18 20:21                                               ` Matan Azrad
2018-01-19  1:41                                                 ` Neil Horman
2018-01-19  7:14                                                   ` Matan Azrad
2018-01-19  9:30                                                     ` Bruce Richardson
2018-01-19 10:44                                                       ` Matan Azrad
2018-01-19 13:30                                                         ` Neil Horman
2018-01-19 13:57                                                           ` Matan Azrad
2018-01-19 14:13                                                           ` Thomas Monjalon
2018-01-19 15:27                                                             ` Neil Horman
2018-01-19 17:17                                                               ` Thomas Monjalon
2018-01-19 17:43                                                                 ` Neil Horman
2018-01-19 18:12                                                                   ` Thomas Monjalon
2018-01-19 19:47                                                                     ` Neil Horman
2018-01-19 20:19                                                                       ` Thomas Monjalon
2018-01-19 22:52                                                                         ` Neil Horman
2018-01-20  3:38                                                                         ` Tuxdriver
2018-01-20 12:54                                                                       ` Ananyev, Konstantin
2018-01-20 14:02                                                                         ` Thomas Monjalon
2018-01-19 12:55                                                       ` Neil Horman
2018-01-19 13:52                                                     ` Neil Horman [this message]
2018-01-18 16:27                                     ` Neil Horman
2018-01-17 17:58                                   ` Matan Azrad
2018-01-18 13:20                                     ` Neil Horman
2018-01-18 14:52                                       ` Matan Azrad
2018-01-19 13:57                                         ` Neil Horman
2018-01-19 14:07                                           ` Thomas Monjalon
2018-01-19 14:32                                             ` Neil Horman
2018-01-19 17:09                                               ` Thomas Monjalon
2018-01-19 17:37                                                 ` Neil Horman
2018-01-19 18:10                                                   ` Thomas Monjalon
2018-01-21 22:12                                                     ` Ferruh Yigit
2018-01-07  9:45   ` [dpdk-dev] [PATCH v2 3/6] ethdev: synchronize port allocation Matan Azrad
2018-01-07  9:58     ` Matan Azrad
2018-01-07  9:45   ` [dpdk-dev] [PATCH v2 4/6] net/failsafe: free an eth port by a dedicated API Matan Azrad
2018-01-07  9:45   ` [dpdk-dev] [PATCH v2 5/6] net/failsafe: use ownership mechanism to own ports Matan Azrad
2018-01-08 10:32     ` Gaëtan Rivet
2018-01-08 11:16       ` Matan Azrad
2018-01-08 11:35         ` Gaëtan Rivet
2018-01-07  9:45   ` [dpdk-dev] [PATCH v2 6/6] app/testpmd: adjust ethdev port ownership Matan Azrad
2018-01-08 11:39     ` Gaëtan Rivet
2018-01-08 12:30       ` Matan Azrad
2018-01-08 13:30         ` Gaëtan Rivet
2018-01-08 13:55           ` Matan Azrad
2018-01-08 14:21             ` Gaëtan Rivet
2018-01-08 14:42               ` Matan Azrad
2018-01-16  5:53     ` Lu, Wenzhuo
2018-01-16  8:15       ` Matan Azrad
2018-01-17  0:46         ` Lu, Wenzhuo
2018-01-17  8:51           ` Matan Azrad
2018-01-18  0:53             ` Lu, Wenzhuo
2018-01-18 16:35   ` [dpdk-dev] [PATCH v3 0/7] Port ownership and syncronization Matan Azrad
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 1/7] ethdev: fix port data reset timing Matan Azrad
2018-01-18 17:00       ` Thomas Monjalon
2018-01-19 12:38       ` Ananyev, Konstantin
2018-03-05 11:24       ` [dpdk-dev] [dpdk-stable] " Ferruh Yigit
2018-03-05 14:52         ` Matan Azrad
2018-03-05 15:06           ` Ferruh Yigit
2018-03-05 15:12             ` Matan Azrad
2018-03-27 22:37               ` Ferruh Yigit
2018-03-28 12:07                 ` Matan Azrad
2018-03-30 10:39                   ` Ferruh Yigit
2018-04-19 11:07                     ` Ferruh Yigit
2018-04-25 12:16                       ` Matan Azrad
2018-04-25 12:30                         ` Ori Kam
2018-04-25 12:54                         ` Ferruh Yigit
2018-04-25 14:01                           ` Matan Azrad
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 2/7] ethdev: fix used portid allocation Matan Azrad
2018-01-18 17:00       ` Thomas Monjalon
2018-01-19 12:40       ` Ananyev, Konstantin
2018-01-20 16:48         ` Matan Azrad
2018-01-20 17:26           ` Ananyev, Konstantin
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 3/7] ethdev: add port ownership Matan Azrad
2018-01-18 21:11       ` Thomas Monjalon
2018-01-19 12:41       ` Ananyev, Konstantin
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 4/7] ethdev: synchronize port allocation Matan Azrad
2018-01-18 20:43       ` Thomas Monjalon
2018-01-18 20:52         ` Matan Azrad
2018-01-18 21:17           ` Thomas Monjalon
2018-01-19 12:47       ` Ananyev, Konstantin
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 5/7] net/failsafe: free an eth port by a dedicated API Matan Azrad
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 6/7] net/failsafe: use ownership mechanism to own ports Matan Azrad
2018-01-18 16:35     ` [dpdk-dev] [PATCH v3 7/7] app/testpmd: adjust ethdev port ownership Matan Azrad
2018-01-19 12:37       ` Ananyev, Konstantin
2018-01-19 12:51         ` Matan Azrad
2018-01-19 13:08           ` Ananyev, Konstantin
2018-01-19 13:35             ` Matan Azrad
2018-01-19 15:00               ` Gaëtan Rivet
2018-01-20 18:14                 ` Matan Azrad
2018-01-22 10:17                   ` Gaëtan Rivet
2018-01-22 11:22                     ` Matan Azrad
2018-01-22 12:28                 ` Ananyev, Konstantin
2018-01-22 13:22                   ` Matan Azrad
2018-01-22 20:48                     ` Ananyev, Konstantin
2018-01-23  8:54                       ` Matan Azrad
2018-01-23 12:56                         ` Gaëtan Rivet
2018-01-23 14:30                           ` Matan Azrad
2018-01-25  9:36                             ` Matan Azrad
2018-01-25 10:05                               ` Thomas Monjalon
2018-01-25 11:15                                 ` Ananyev, Konstantin
2018-01-25 11:33                                   ` Thomas Monjalon
2018-01-25 11:55                                     ` Ananyev, Konstantin
2018-01-23 13:34                         ` Ananyev, Konstantin
2018-01-23 14:18                           ` Thomas Monjalon
2018-01-23 15:12                             ` Ananyev, Konstantin
2018-01-23 15:18                               ` Ananyev, Konstantin
2018-01-23 17:33                                 ` Thomas Monjalon
2018-01-23 21:18                                   ` Ananyev, Konstantin
2018-01-24  8:10                                     ` Thomas Monjalon
2018-01-24 18:30                                       ` Ananyev, Konstantin
2018-01-25 10:55                                         ` Thomas Monjalon
2018-01-25 11:09                                           ` Ananyev, Konstantin
2018-01-25 11:27                                             ` Thomas Monjalon
2018-01-23 14:43                           ` Matan Azrad
2018-01-20 21:24     ` [dpdk-dev] [PATCH v4 0/7] Port ownership and syncronization Matan Azrad
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 1/7] ethdev: fix port data reset timing Matan Azrad
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 2/7] ethdev: fix used portid allocation Matan Azrad
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 3/7] ethdev: add port ownership Matan Azrad
2018-01-21 20:43         ` Ferruh Yigit
2018-01-21 20:46         ` Ferruh Yigit
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 4/7] ethdev: synchronize port allocation Matan Azrad
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 5/7] net/failsafe: free an eth port by a dedicated API Matan Azrad
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 6/7] net/failsafe: use ownership mechanism to own ports Matan Azrad
2018-01-20 21:24       ` [dpdk-dev] [PATCH v4 7/7] app/testpmd: adjust ethdev port ownership Matan Azrad
2018-01-22 16:38       ` [dpdk-dev] [PATCH v5 0/7] Port ownership and synchronization Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 1/7] ethdev: fix port data reset timing Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 2/7] ethdev: fix used portid allocation Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 3/7] ethdev: add port ownership Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 4/7] ethdev: synchronize port allocation Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 5/7] net/failsafe: free an eth port by a dedicated API Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 6/7] net/failsafe: use ownership mechanism to own ports Matan Azrad
2018-01-22 16:38         ` [dpdk-dev] [PATCH v5 7/7] app/testpmd: adjust ethdev port ownership Matan Azrad
2018-01-25  1:47           ` Lu, Wenzhuo
2018-01-25  8:30             ` Matan Azrad
2018-01-26  0:50               ` Lu, Wenzhuo
2018-01-29 11:21         ` [dpdk-dev] [PATCH v5 0/7] Port ownership and synchronization Matan Azrad
2018-01-31 19:53           ` Thomas Monjalon
2018-01-25 14:35     ` [dpdk-dev] [PATCH v3 0/7] Port ownership and syncronization Ferruh Yigit

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