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From: Thomas Monjalon <thomas.monjalon@6wind.com>
To: Shreyansh Jain <shreyansh.jain@nxp.com>
Cc: david.marchand@6wind.com, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v5 01/12] eal/bus: introduce bus abstraction
Date: Fri, 06 Jan 2017 15:55:48 +0100	[thread overview]
Message-ID: <105987546.PAaz77144n@xps13> (raw)
In-Reply-To: <d2513eef-f231-b96e-c763-55d632d8598a@nxp.com>

2017-01-06 16:01, Shreyansh Jain:
> On Wednesday 04 January 2017 03:22 AM, Thomas Monjalon wrote:
> > 2016-12-26 18:53, Shreyansh Jain:
> >> +/**
> >> + * A structure describing a generic bus.
> >> + */
> >> +struct rte_bus {
> >> +	TAILQ_ENTRY(rte_bus) next;   /**< Next bus object in linked list */
> >> +	struct rte_driver_list driver_list;
> >> +				     /**< List of all drivers on bus */
> >> +	struct rte_device_list device_list;
> >> +				     /**< List of all devices on bus */
> >> +	const char *name;            /**< Name of the bus */
> >> +};
> >
> > I am not convinced we should link a generic bus to drivers and devices.
> > What do you think of having rte_pci_bus being a rte_bus and linking
> > with rte_pci_device and rte_pci_driver lists?
> 
> This is different from what I had in mind.
> You are saying:
> 
>   Class: rte_bus
>        `-> No object instantiated for this class
>   Class: rte_pci_bus inheriting rte_bus
>        `-> object instantiated for this class.
> 
> Here, rte_bus is being treated as an abstract class which is only 
> inherited and rte_pci_bus is the base class which is instantiated.
> 
> And I was thinking:
> 
>   Class: rte_bus
>        `-> Object: pci_bus (defined in */eal/eal_pci.c)
> 
> Here, rte_bus is that base class which is instantiated.
> 
> I agree that what you are suggesting is inline with current model:
>   rte_device -> abstract class (no one instantiates it)
>    `-> rte_pci_device -> Base class which inherits rte_device and
>                          is instantiated.

Yes

> When I choose not to create rte_pci_bus, it was because I didn't want 
> another indirection in form of rte_bus->rte_pci_bus->object.
> There were no 'non-generic' bus functions which were only applicable for 
> rte_pci_bus. Eventually, rte_pci_bus ended up being a direct inheritance 
> of rte_bus.
> 
> > I'm thinking to something like that:
> >
> > struct rte_bus {
> > 	TAILQ_ENTRY(rte_bus) next;
> > 	const char *name;
> > 	rte_bus_scan_t scan;
> > 	rte_bus_match_t match;
> > };
> > struct rte_pci_bus {
> > 	struct rte_bus bus;
> > 	struct rte_pci_driver_list pci_drivers;
> > 	struct rte_pci_device_list pci_devices;
> > };
> 
> if we go by rte_bus->rte_pci_bus->(instance of rte_pci_bus), above is 
> fine. Though, I am in favor of rte_bus->(instance of rte_bus for PCI) 
> because I don't see any 'non-generic' information in rte_pci_bus which 
> can't be put in rte_bus.

The lists of drivers and devices are specific to the bus.
Your proposal was to list them as generic rte_driver/rte_device and
cast them. I'm just saying we can directly declare them with the right type,
e.g. rte_pci_driver/rte_pci_device.

In the same logic, the functions probe/remove are specifics for the bus and
should be declared in rte_pci_driver instead of the generic rte_driver.


> >> +/** Helper for Bus registration. The constructor has higher priority than
> >> + * PMD constructors
> >> + */
> >> +#define RTE_REGISTER_BUS(nm, bus) \
> >> +static void __attribute__((constructor(101), used)) businitfn_ ##nm(void) \
> >> +{\
> >> +	(bus).name = RTE_STR(nm);\
> >> +	rte_eal_bus_register(&bus); \
> >> +}
> >
> > By removing the lists from rte_bus as suggested above, do you still need
> > a priority for this constructor?
> 
> I think yes.
> Even if we have rte_pci_bus as a class, object of rte_bus should be part 
> of Bus list *before* registration of a driver (because, driver 
> registration searches for bus by name).
> 
> (This is assuming that no global PCI/VDEV/XXX bus object is created 
> which is directly used within all PCI specific bus operations).
> 
> There was another suggestion on list which was to check for existence of 
> bus _within_ each driver registration and create/instantiate an object 
> in case no bus is registered. I didn't like the approach so I didn't use 
> it. From David [1], and me [2]
> 
> [1] http://dpdk.org/ml/archives/dev/2016-December/051689.html
> [2] http://dpdk.org/ml/archives/dev/2016-December/051698.html

OK, we can keep your approach of prioritize bus registrations.
If we see an issue later, we could switch to a bus registration done
when a first driver is registered on the bus.


> >>  struct rte_device {
> >>  	TAILQ_ENTRY(rte_device) next; /**< Next device */
> >> +	struct rte_bus *bus;          /**< Device connected to this bus */
> >>  	const struct rte_driver *driver;/**< Associated driver */
> >>  	int numa_node;                /**< NUMA node connection */
> >>  	struct rte_devargs *devargs;  /**< Device user arguments */
> >> @@ -148,6 +149,7 @@ void rte_eal_device_remove(struct rte_device *dev);
> >>   */
> >>  struct rte_driver {
> >>  	TAILQ_ENTRY(rte_driver) next;  /**< Next in list. */
> >> +	struct rte_bus *bus;           /**< Bus serviced by this driver */
> >>  	const char *name;                   /**< Driver name. */
> >>  	const char *alias;              /**< Driver alias. */
> >>  };
> >
> > Do we need to know the bus associated to a driver in rte_driver?
> > Bus and driver are already associated in rte_device.
> 
> Two reasons:
> 1/ A driver should be associated with a bus so that if required, all bus 
> can be directly extracted - even when probing has not been done.

I do not understand this need.

> 2/ device->driver would only be updated after probe. device->driver->bus 
> would not be valid in such cases, if required.

We can update device->driver on match.

Please let's do not over-engineer if not needed.
In this case, I think we can skip rte_driver->bus.


> Overall, I don't have objections for rte_bus->rte_pci_bus=>object as 
> compared to rte_bus=>PCI-object. But, I would still like to get a final 
> confirmation of a more preferred way.
> 
> Meanwhile, I will make changes to accommodate this change to save time 
> in case rte_pci_bus class is final/preferred method.

It looks more natural to me to avoid class casting and use specialized classes
when possible. So yes I prefer instantiating rte_pci_bus.
However, I could be wrong, and will consider any argument.

Thanks

  reply	other threads:[~2017-01-06 14:55 UTC|newest]

Thread overview: 132+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-12-04 10:11 [dpdk-dev] [PATCH 00/13] Introducing EAL Bus-Device-Driver Model Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 01/13] eal: define container_of macro Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 02/13] eal/bus: introduce bus abstraction Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 03/13] test: add basic bus infrastructure tests Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 04/13] eal/bus: add scan and match support Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 05/13] eal/bus: add support for inserting a device on a bus Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 06/13] eal: integrate bus scan and probe with EAL Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 07/13] pci: replace probe and remove handlers with rte_driver Shreyansh Jain
2016-12-08 17:50   ` Ferruh Yigit
2016-12-09  4:59     ` Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 08/13] eal: enable probe and remove from bus infrastructure Shreyansh Jain
2016-12-06 10:45   ` Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 09/13] pci: split match and probe function Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 10/13] eal/pci: generalize args of PCI scan/match towards RTE device/driver Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 11/13] pci: Pass rte_pci_addr to functions instead of separate args Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 12/13] eal: enable PCI bus Shreyansh Jain
2016-12-04 10:11 ` [dpdk-dev] [PATCH 13/13] eal/pci: remove PCI probe and init calls Shreyansh Jain
2016-12-06 20:52 ` [dpdk-dev] [PATCH 00/13] Introducing EAL Bus-Device-Driver Model David Marchand
2016-12-07  9:55   ` Shreyansh Jain
2016-12-07 12:17     ` David Marchand
2016-12-07 13:10       ` Shreyansh Jain
2016-12-07 13:24         ` Thomas Monjalon
2016-12-08  5:04           ` Shreyansh Jain
2016-12-08  7:21             ` Thomas Monjalon
2016-12-08  7:53               ` Shreyansh Jain
2016-12-12 14:35         ` Jianbo Liu
2016-12-13  6:56           ` Shreyansh Jain
2016-12-13 13:37 ` [dpdk-dev] [PATCH v2 00/12] " Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 01/12] eal: define container_of macro Shreyansh Jain
2016-12-13 22:24     ` Jan Blunck
2016-12-14  5:12       ` Shreyansh Jain
2016-12-16  8:14         ` Jan Blunck
2016-12-16  9:23           ` Adrien Mazarguil
2016-12-16 10:47             ` Jan Blunck
2016-12-16 11:21               ` Adrien Mazarguil
2016-12-16 11:54                 ` Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 02/12] eal/bus: introduce bus abstraction Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 03/12] test: add basic bus infrastructure tests Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 04/12] eal/bus: add scan, match and insert support Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 05/12] eal: integrate bus scan and probe with EAL Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 06/12] eal: add probe and remove support for rte_driver Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 07/12] eal: enable probe from bus infrastructure Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 08/12] pci: split match and probe function Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 09/12] eal/pci: generalize args of PCI scan/match towards RTE device/driver Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 10/12] pci: Pass rte_pci_addr to functions instead of separate args Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 11/12] eal: enable PCI bus Shreyansh Jain
2016-12-13 13:37   ` [dpdk-dev] [PATCH v2 12/12] drivers: update PMDs to use rte_driver probe and remove Shreyansh Jain
2016-12-13 13:52     ` Andrew Rybchenko
2016-12-13 15:07       ` Ferruh Yigit
2016-12-14  5:14         ` Shreyansh Jain
2016-12-14  5:11       ` Shreyansh Jain
2016-12-14  9:49     ` Shreyansh Jain
2016-12-15 21:36       ` Jan Blunck
2016-12-26  9:14         ` Shreyansh Jain
2016-12-16 13:10   ` [dpdk-dev] [PATCH v3 00/12] Introducing EAL Bus-Device-Driver Model Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 01/12] eal: define container_of macro Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 02/12] eal/bus: introduce bus abstraction Shreyansh Jain
2016-12-20 12:37       ` Hemant Agrawal
2016-12-20 13:17       ` Jan Blunck
2016-12-20 13:51         ` Shreyansh Jain
2016-12-20 17:11         ` Stephen Hemminger
2016-12-21  7:11           ` Shreyansh Jain
2016-12-21 15:38           ` Jan Blunck
2016-12-21 23:33             ` Stephen Hemminger
2016-12-22  5:12               ` Shreyansh Jain
2016-12-22  5:52                 ` Shreyansh Jain
2016-12-25 17:39         ` Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 03/12] test: add basic bus infrastructure tests Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 04/12] eal/bus: add scan, match and insert support Shreyansh Jain
2016-12-16 13:25       ` Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 05/12] eal: integrate bus scan and probe with EAL Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 06/12] eal: add probe and remove support for rte_driver Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 07/12] eal: enable probe from bus infrastructure Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 08/12] pci: split match and probe function Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 09/12] eal/pci: generalize args of PCI scan/match towards RTE device/driver Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 10/12] pci: Pass rte_pci_addr to functions instead of separate args Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 11/12] eal: enable PCI bus and PCI test framework Shreyansh Jain
2016-12-16 13:20       ` Shreyansh Jain
2016-12-16 13:10     ` [dpdk-dev] [PATCH v3 12/12] drivers: update PMDs to use rte_driver probe and remove Shreyansh Jain
2016-12-26 12:50     ` [dpdk-dev] [PATCH v4 00/12] Introducing EAL Bus-Device-Driver Model Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 01/12] eal/bus: introduce bus abstraction Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 02/12] test: add basic bus infrastructure tests Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 03/12] eal/bus: add scan, match and insert support Shreyansh Jain
2016-12-26 13:27         ` Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 04/12] eal: integrate bus scan and probe with EAL Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 05/12] eal: add probe and remove support for rte_driver Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 06/12] eal: enable probe from bus infrastructure Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 07/12] pci: split match and probe function Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 08/12] eal/pci: generalize args of PCI scan/match towards RTE device/driver Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 09/12] pci: Pass rte_pci_addr to functions instead of separate args Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 10/12] eal: enable PCI bus and PCI test framework Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 11/12] drivers: update PMDs to use rte_driver probe and remove Shreyansh Jain
2016-12-26 12:50       ` [dpdk-dev] [PATCH v4 12/12] eal/bus: add bus iteration macros Shreyansh Jain
2016-12-26 13:23       ` [dpdk-dev] [PATCH v5 00/12] Introducing EAL Bus-Device-Driver Model Shreyansh Jain
2016-12-26 13:23         ` [dpdk-dev] [PATCH v5 01/12] eal/bus: introduce bus abstraction Shreyansh Jain
2017-01-03 21:52           ` Thomas Monjalon
2017-01-06 10:31             ` Shreyansh Jain
2017-01-06 14:55               ` Thomas Monjalon [this message]
2017-01-09  6:24                 ` Shreyansh Jain
2017-01-09 15:22           ` Ferruh Yigit
2017-01-10  4:07             ` Shreyansh Jain
2016-12-26 13:23         ` [dpdk-dev] [PATCH v5 02/12] test: add basic bus infrastructure tests Shreyansh Jain
2016-12-26 13:23         ` [dpdk-dev] [PATCH v5 03/12] eal/bus: add scan, match and insert support Shreyansh Jain
2016-12-26 13:23         ` [dpdk-dev] [PATCH v5 04/12] eal: integrate bus scan and probe with EAL Shreyansh Jain
2017-01-03 21:46           ` Thomas Monjalon
2017-01-06 10:38             ` Shreyansh Jain
2017-01-06 12:00               ` Shreyansh Jain
2017-01-06 13:46                 ` Thomas Monjalon
2017-01-09  6:35                   ` Shreyansh Jain
2017-01-08 12:21           ` Rosen, Rami
2017-01-09  6:34             ` Shreyansh Jain
2016-12-26 13:23         ` [dpdk-dev] [PATCH v5 05/12] eal: add probe and remove support for rte_driver Shreyansh Jain
2017-01-03 22:05           ` Thomas Monjalon
2017-01-06 11:44             ` Shreyansh Jain
2017-01-06 15:26               ` Thomas Monjalon
2017-01-09  6:28                 ` Shreyansh Jain
2016-12-26 13:23         ` [dpdk-dev] [PATCH v5 06/12] eal: enable probe from bus infrastructure Shreyansh Jain
2016-12-26 13:24         ` [dpdk-dev] [PATCH v5 07/12] pci: split match and probe function Shreyansh Jain
2017-01-03 22:08           ` Thomas Monjalon
2016-12-26 13:24         ` [dpdk-dev] [PATCH v5 08/12] eal/pci: generalize args of PCI scan/match towards RTE device/driver Shreyansh Jain
2017-01-03 22:13           ` Thomas Monjalon
2017-01-06 12:03             ` Shreyansh Jain
2016-12-26 13:24         ` [dpdk-dev] [PATCH v5 09/12] pci: Pass rte_pci_addr to functions instead of separate args Shreyansh Jain
2016-12-26 13:24         ` [dpdk-dev] [PATCH v5 10/12] eal: enable PCI bus and PCI test framework Shreyansh Jain
2016-12-26 13:24         ` [dpdk-dev] [PATCH v5 11/12] drivers: update PMDs to use rte_driver probe and remove Shreyansh Jain
2017-01-09 15:19           ` Ferruh Yigit
2017-01-09 16:18             ` Ferruh Yigit
2017-01-10  4:09               ` Shreyansh Jain
2016-12-26 13:24         ` [dpdk-dev] [PATCH v5 12/12] eal/bus: add bus iteration macros Shreyansh Jain
2017-01-03 22:15           ` Thomas Monjalon
2017-01-03 22:22         ` [dpdk-dev] [PATCH v5 00/12] Introducing EAL Bus-Device-Driver Model Thomas Monjalon
2017-01-06  6:27           ` Shreyansh Jain

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