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From: "Yigit, Ferruh" <ferruh.yigit@linux.intel.com>
To: Nithin Dabilpuram <nithind1988@gmail.com>,
	Thomas Monjalon <thomas@monjalon.net>
Cc: dev@dpdk.org, Wenzhuo Lu <wenzhuo.lu@intel.com>,
	Jingjing Wu <jingjing.wu@intel.com>,
	Bernard Iremonger <bernard.iremonger@intel.com>,
	ndabilpuram@marvell.com, jerinj@marvell.com
Subject: Re: [dpdk-dev] [PATCH] app/testpmd: change port detach interface
Date: Tue, 2 Jul 2019 16:58:17 +0100	[thread overview]
Message-ID: <d0303671-eb68-2cc4-1736-ef70bb15ecb3@linux.intel.com> (raw)
In-Reply-To: <20190529081620.GA5044@gmail.com>

On 5/29/2019 9:16 AM, Nithin Dabilpuram wrote:
> Hi Thomas,
> 
> On Mon, May 20, 2019 at 06:20:53PM +0530, Nithin Dabilpuram wrote:
>> On Fri, May 17, 2019 at 10:59:38AM +0200, Thomas Monjalon wrote:
>>> 17/05/2019 10:55, Nithin Dabilpuram:
>>>> On Wed, May 15, 2019 at 09:27:22AM +0200, Thomas Monjalon wrote:
>>>>> 15/05/2019 08:52, Nithin Dabilpuram:
>>>>>> Hi Thomas,
>>>>>> On Tue, May 14, 2019 at 05:39:30PM +0200, Thomas Monjalon wrote:
>>>>>>> Hi,
>>>>>>>
>>>>>>> 13/05/2019 13:21, Nithin Dabilpuram:
>>>>>>>> With the latest published interface of
>>>>>>>> rte_eal_hotplug_[add,remove](), and rte_eth_dev_close(),
>>>>>>>> rte_eth_dev_close() would cleanup all the data structures of
>>>>>>>> port's eth dev leaving the device common resource intact
>>>>>>>> if RTE_ETH_DEV_CLOSE_REMOVE is set in dev flags.
>>>>>>>> So "port detach" (~hotplug remove) should be able to work,
>>>>>>>> with device identifier like "port attach" as eth_dev could have
>>>>>>>> been closed already and rte_eth_devices[port_id] reused.
>>>>>>>
>>>>>>> "port attach" uses devargs as identifier because there
>>>>>>> is no port id before creating it. But "detach port" uses
>>>>>>> logically the port id to close.
>>>>>>
>>>>>> But if "port close" was already called on that port,
>>>>>> eth_dev->state would be set as RTE_ETH_DEV_UNUSED and
>>>>>> that port id could be reused.
>>>>>> So after "port close" if we call "port detach", isn't it
>>>>>> incorrect to use the same port id ?
>>>>>
>>>>> Yes it is incorrect to close a port which is already closed :)
>>>>>
>>>>>>>> This change alters "port detach" cmdline interface to
>>>>>>>> work with device identifier like "port attach".
>>>>>>>
>>>>>>> The word "port" means an ethdev port, so it should be
>>>>>>> referenced with a port id.
>>>>>>> If you want to close an EAL rte_device, then you should
>>>>>>> rename the command.
>>>>>>> But testpmd purpose should be to work with ethdev ports only.
>>>>>>
>>>>>> Renaming the command to "detach <identifier>" ?
>>>>>
>>>>> Yes something like that.
>>>>> But why do you want to manage rte_device in testpmd?
>>>>> Being able to close ports in not enough?
>>>>> Please describe a scenario.
>>>>>
>>>>
>>>> We just want to support testing hotplug detach along with
>>>> hotplug attach from testpmd. Currently there is no way to detach
>>>> if we close the port first.
>>>
>>> OK
>> So can I send next revision with command renamed to "detach <identifier>" ?
> 
> Any info on this ? I can even add it as another cmd without disturbing existing
> command if needed.

This sounds better option to me. I see the need to remove device via
'identifier' but also still it is easier to use 'port_id' for removal when
applicable, so I am for keeping it.

What do you think adding a new command:
'device detach'

Also testpmd doesn't dead with 'device' much, it mainly works in port level,
because of this does it make sense to add another command something like:
"show device info all"

> 
>>>
>>>> Another reason is that in our new PMD, for detaching one specific port,
>>>> we need more than one try as the PMD might return -EAGAIN.
>>>> So with the current "port detach" implementation, after closing the port,
>>>> if PMD returns -EAGAIN for rte_dev_remove() call, there is no way to
>>>> try it again.
>>>
>>> This is a bug.
>>> Should we catch -EAGAIN somewhere?
>>
>> It is already caught in local_dev_remove() and
>> rte_dev_remove() fails. Only problem as I said below is
>> in testpmd if first call to detach_port_device() i.e handler of "port detach", 
>> rte_dev_remove() returns -EAGAIN and PMD cleaned up the resources partially like eth_dev
>> resources, the second time call cannot work port_id will not be valid anymore.
>>
>>>
>>>


  parent reply	other threads:[~2019-07-02 15:58 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-13 11:21 Nithin Dabilpuram
2019-05-13 11:21 ` Nithin Dabilpuram
2019-05-14 15:39 ` Thomas Monjalon
2019-05-14 15:39   ` Thomas Monjalon
2019-05-15  6:52   ` Nithin Dabilpuram
2019-05-15  6:52     ` Nithin Dabilpuram
2019-05-15  7:27     ` Thomas Monjalon
2019-05-15  7:27       ` Thomas Monjalon
2019-05-17  8:55       ` Nithin Dabilpuram
2019-05-17  8:59         ` Thomas Monjalon
2019-05-20 12:50           ` Nithin Dabilpuram
2019-05-29  8:16             ` Nithin Dabilpuram
2019-06-25  4:24               ` Nithin Dabilpuram
2019-07-02 15:58               ` Yigit, Ferruh [this message]
2019-07-03  5:05                 ` Nithin Dabilpuram
2019-07-10 13:07 ` [dpdk-dev] [PATCH v2] app/testpmd: add device related cmds Nithin Dabilpuram
2019-07-16 18:30   ` Ferruh Yigit
2019-07-17  8:08     ` [dpdk-dev] [EXT] " Nithin Kumar Dabilpuram
2019-07-17 12:30 ` [dpdk-dev] [PATCH v3] " Nithin Dabilpuram
2019-07-17 16:51   ` Ferruh Yigit
2019-07-18  5:27     ` [dpdk-dev] [EXT] " Nithin Kumar Dabilpuram
2019-07-19 19:00       ` Ferruh Yigit
2019-07-22  6:01         ` Hemant Agrawal
2019-07-22  6:15           ` Nithin Kumar Dabilpuram
2019-07-22 16:04             ` Ferruh Yigit
2019-07-17 16:54   ` [dpdk-dev] " Ferruh Yigit

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