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From: Matan Azrad <matan@mellanox.com>
To: Ferruh Yigit <ferruh.yigit@intel.com>,
	Adrien Mazarguil <adrien.mazarguil@6wind.com>,
	Gaetan Rivet <gaetan.rivet@6wind.com>
Cc: Thomas Monjalon <thomas@monjalon.net>, "dev@dpdk.org" <dev@dpdk.org>
Subject: Re: [dpdk-dev] [PATCH v6 1/6] ethdev: add devop to check removal status
Date: Thu, 18 Jan 2018 18:02:28 +0000	[thread overview]
Message-ID: <AM6PR0502MB3797834CD3A0945D075A4AD8D2E80@AM6PR0502MB3797.eurprd05.prod.outlook.com> (raw)
In-Reply-To: <2ffac5e9-6be5-0c82-18c4-8b72710630ae@intel.com>

Hi Ferruh

From: Ferruh Yigit, Thursday, January 18, 2018 7:18 PM
> On 1/18/2018 11:27 AM, Matan Azrad wrote:
> > There is time between the physical removal of the device until PMDs
> > get a RMV interrupt. At this time DPDK PMDs and applications still
> > don't know about the removal.
> >
> > Current removal detection is achieved only by registration to device
> > RMV event and the notification comes asynchronously. So, there is no
> > option to detect a device removal synchronously.
> > Applications and other DPDK entities may want to check a device
> > removal synchronously and to take an immediate decision accordingly.
> 
> So we will have two methods to detect device removal, one is asynchronous
> as you mentioned.
> Device removal will cause an interrupt which trigger to run user callback.

Yes.

> New method is synchronous, but still triggered from application. I mean
> application should do a rte_eth_dev_is_removed() to learn about status,
> what is the use case here, polling continuously? Won't this also cause some
> latency unless you dedicate a core just polling device status?
> 

It is for application and for other DPDK entities like PMDs, see fail-safe example in this series.
When hotplug in the game I think it can be used for application too.

> > Add new dev op called is_removed to allow DPDK entities to check an
> > Ethernet device removal status immediately.
> >
> > Signed-off-by: Matan Azrad <matan@mellanox.com>
> > Acked-by: Thomas Monjalon <thomas@monjalon.net>
> > ---
> >  lib/librte_ether/rte_ethdev.c           | 28 +++++++++++++++++++++++++---
> >  lib/librte_ether/rte_ethdev.h           | 20 ++++++++++++++++++++
> >  lib/librte_ether/rte_ethdev_version.map |  1 +
> >  3 files changed, 46 insertions(+), 3 deletions(-)
> >
> > diff --git a/lib/librte_ether/rte_ethdev.c
> > b/lib/librte_ether/rte_ethdev.c index b349599..c93cec1 100644
> > --- a/lib/librte_ether/rte_ethdev.c
> > +++ b/lib/librte_ether/rte_ethdev.c
> > @@ -114,7 +114,8 @@ enum {
> >  rte_eth_find_next(uint16_t port_id)
> >  {
> >  	while (port_id < RTE_MAX_ETHPORTS &&
> > -	       rte_eth_devices[port_id].state != RTE_ETH_DEV_ATTACHED)
> > +	       rte_eth_devices[port_id].state != RTE_ETH_DEV_ATTACHED &&
> > +	       rte_eth_devices[port_id].state != RTE_ETH_DEV_REMOVED)
> 
> If device is removed, why we are not allowed to re-use port_id assigned to
> it?
Sorry, don't understand.
We allow still to iterate over it here.

> Overall I am not clear with RTE_ETH_DEV_REMOVED state, why we are not
> directly setting RTE_ETH_DEV_UNUSED?
 
Someone should release the SW port resources before setting it to UNUSED.

> And state RTE_ETH_DEV_REMOVED set in ethdev layer, and ethdev layer
> won't let reusing it, so what changes the state of dev? Will it stay as it is
> during lifetime of the application?
> 
> >  		port_id++;
> >
> >  	if (port_id >= RTE_MAX_ETHPORTS)
> > @@ -262,8 +263,7 @@ struct rte_eth_dev *
> > rte_eth_dev_is_valid_port(uint16_t port_id)  {
> >  	if (port_id >= RTE_MAX_ETHPORTS ||
> > -	    (rte_eth_devices[port_id].state != RTE_ETH_DEV_ATTACHED &&
> > -	     rte_eth_devices[port_id].state != RTE_ETH_DEV_DEFERRED))
> > +	    (rte_eth_devices[port_id].state == RTE_ETH_DEV_UNUSED))
> >  		return 0;
> >  	else
> >  		return 1;
> > @@ -1094,6 +1094,28 @@ struct rte_eth_dev *  }
> >
> >  int
> > +rte_eth_dev_is_removed(uint16_t port_id) {
> > +	struct rte_eth_dev *dev;
> > +	int ret;
> > +
> > +	RTE_ETH_VALID_PORTID_OR_ERR_RET(port_id, 0);
> > +
> > +	dev = &rte_eth_devices[port_id];
> > +
> > +	RTE_FUNC_PTR_OR_ERR_RET(*dev->dev_ops->is_removed, 0);
> > +
> > +	if (dev->state == RTE_ETH_DEV_REMOVED)
> > +		return 1;
> 
> Isn't this conflict with below API documentation:
> 

Yes, You absolutely right, we need to change this documentation.

> "
>  * @return
>  *   - 0 when the Ethernet device is removed, otherwise 1.
> "
> 
> > +
> > +	ret = dev->dev_ops->is_removed(dev);
> > +	if (ret != 0)
> > +		dev->state = RTE_ETH_DEV_REMOVED;
> 
> It isn't clear what "dev_ops->is_removed(dev)" should return, and this
> causing incompatible usages in PMDs by time.
> Please add some documentation about expected return values for dev_ops.
>

OK
 
> 
> And this not real remove, PMD signals us and we stop using that device, but
> device can be there, right?

It says that the device is physically removed but there is some software resources which still were not released.

> If there is a real removal, can be possible to use eal hotplug?

I think EAL hotplug is asynchrony  as the current RMV event , so EAl hotplug event can be used instead of RMV event.
 


> <...>

  parent reply	other threads:[~2018-01-18 18:02 UTC|newest]

Thread overview: 98+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-11-02 15:42 [dpdk-dev] [PATCH 0/3] Fail-safe fix removal handling lack Matan Azrad
2017-11-02 15:42 ` [dpdk-dev] [PATCH 1/3] net/failsafe: " Matan Azrad
2017-11-06  8:19   ` Gaëtan Rivet
2017-11-02 15:42 ` [dpdk-dev] [PATCH 2/3] net/mlx4: adjust removal error Matan Azrad
2017-11-03 13:05   ` Adrien Mazarguil
2017-11-05  6:52     ` Matan Azrad
2017-11-06 16:51       ` Adrien Mazarguil
2017-11-02 15:42 ` [dpdk-dev] [PATCH 3/3] net/mlx5: " Matan Azrad
2017-11-03 13:06   ` Adrien Mazarguil
2017-11-05  6:57     ` Matan Azrad
2017-12-13 14:29 ` [dpdk-dev] [PATCH v2 0/4] Fail-safe fix removal handling lack Matan Azrad
2017-12-13 14:29   ` [dpdk-dev] [PATCH v2 1/4] ethdev: add devop to check removal status Matan Azrad
2017-12-13 14:29   ` [dpdk-dev] [PATCH v2 2/4] net/mlx4: support a device removal check operation Matan Azrad
2017-12-13 14:29   ` [dpdk-dev] [PATCH v2 3/4] net/mlx5: " Matan Azrad
2017-12-13 14:29   ` [dpdk-dev] [PATCH v2 4/4] net/failsafe: fix removed device handling Matan Azrad
2017-12-13 15:16     ` Gaëtan Rivet
2017-12-13 15:48       ` Matan Azrad
2017-12-13 16:09         ` Gaëtan Rivet
2017-12-13 17:09           ` Thomas Monjalon
2017-12-14 10:40             ` Matan Azrad
2017-12-13 21:55           ` Gaëtan Rivet
2017-12-14 10:40             ` Matan Azrad
2017-12-14 10:48               ` Gaëtan Rivet
2017-12-14 13:07                 ` Matan Azrad
2017-12-14 13:27                   ` Gaëtan Rivet
2017-12-14 14:43                     ` Matan Azrad
2017-12-19 17:10   ` [dpdk-dev] [PATCH v3 0/6] Fail-safe\ethdev: fix removal handling lack Matan Azrad
2017-12-19 17:10     ` [dpdk-dev] [PATCH v3 1/6] ethdev: add devop to check removal status Matan Azrad
2017-12-19 17:20       ` Stephen Hemminger
2017-12-19 17:24         ` Matan Azrad
2017-12-19 20:51           ` Thomas Monjalon
2017-12-19 22:13             ` Gaëtan Rivet
2017-12-20  8:39               ` Matan Azrad
2018-01-07  9:53       ` Thomas Monjalon
2017-12-19 17:10     ` [dpdk-dev] [PATCH v3 2/6] net/mlx4: support a device removal check operation Matan Azrad
2017-12-19 17:10     ` [dpdk-dev] [PATCH v3 3/6] net/mlx5: " Matan Azrad
2017-12-19 17:10     ` [dpdk-dev] [PATCH v3 4/6] ethdev: adjust APIs removal error report Matan Azrad
2018-01-07  9:56       ` Thomas Monjalon
2017-12-19 17:10     ` [dpdk-dev] [PATCH v3 5/6] ethdev: adjust flow " Matan Azrad
2018-01-07  9:58       ` Thomas Monjalon
2017-12-19 17:10     ` [dpdk-dev] [PATCH v3 6/6] net/failsafe: fix removed device handling Matan Azrad
2017-12-19 22:21       ` Gaëtan Rivet
2017-12-20 10:58         ` Matan Azrad
2018-01-08 10:57           ` Gaëtan Rivet
2018-01-08 12:55             ` Matan Azrad
2018-01-08 13:46               ` Gaëtan Rivet
2018-01-08 14:00                 ` Matan Azrad
2018-01-08 14:31                   ` Gaëtan Rivet
2018-01-10 12:30     ` [dpdk-dev] [PATCH v4 0/6] Fail-safe\ethdev: fix removal handling lack Matan Azrad
2018-01-10 12:31       ` [dpdk-dev] [PATCH v4 1/6] ethdev: add devop to check removal status Matan Azrad
2018-01-10 12:31       ` [dpdk-dev] [PATCH v4 2/6] net/mlx4: support a device removal check operation Matan Azrad
2018-01-10 12:31       ` [dpdk-dev] [PATCH v4 3/6] net/mlx5: " Matan Azrad
2018-01-10 12:31       ` [dpdk-dev] [PATCH v4 4/6] ethdev: adjust APIs removal error report Matan Azrad
2018-01-10 12:31       ` [dpdk-dev] [PATCH v4 5/6] ethdev: adjust flow " Matan Azrad
2018-01-10 12:31       ` [dpdk-dev] [PATCH v4 6/6] net/failsafe: fix removed device handling Matan Azrad
2018-01-10 12:43         ` Matan Azrad
2018-01-10 13:51           ` Gaëtan Rivet
2018-01-10 13:47         ` Gaëtan Rivet
2018-01-17 20:19       ` [dpdk-dev] [PATCH v5 0/6] Fail-safe\ethdev: fix removal handling lack Matan Azrad
2018-01-17 20:19         ` [dpdk-dev] [PATCH v5 1/6] ethdev: add devop to check removal status Matan Azrad
2018-01-17 20:40           ` Ferruh Yigit
2018-01-17 20:19         ` [dpdk-dev] [PATCH v5 2/6] net/mlx4: support a device removal check operation Matan Azrad
2018-01-17 20:19         ` [dpdk-dev] [PATCH v5 3/6] net/mlx5: " Matan Azrad
2018-01-17 20:19         ` [dpdk-dev] [PATCH v5 4/6] ethdev: adjust APIs removal error report Matan Azrad
2018-01-17 20:19         ` [dpdk-dev] [PATCH v5 5/6] ethdev: adjust flow " Matan Azrad
2018-01-17 20:19         ` [dpdk-dev] [PATCH v5 6/6] net/failsafe: fix removed device handling Matan Azrad
2018-01-18  8:44           ` Gaëtan Rivet
2018-01-18 11:27         ` [dpdk-dev] [PATCH v6 0/6] Fail-safe\ethdev: fix removal handling lack Matan Azrad
2018-01-18 11:27           ` [dpdk-dev] [PATCH v6 1/6] ethdev: add devop to check removal status Matan Azrad
2018-01-18 17:18             ` Ferruh Yigit
2018-01-18 17:57               ` Adrien Mazarguil
2018-01-18 18:02               ` Matan Azrad [this message]
2018-01-18 11:27           ` [dpdk-dev] [PATCH v6 2/6] net/mlx4: support a device removal check operation Matan Azrad
2018-01-18 16:59             ` Adrien Mazarguil
2018-01-18 11:27           ` [dpdk-dev] [PATCH v6 3/6] net/mlx5: " Matan Azrad
2018-01-18 16:59             ` Adrien Mazarguil
2018-01-18 11:27           ` [dpdk-dev] [PATCH v6 4/6] ethdev: adjust APIs removal error report Matan Azrad
2018-01-18 17:31             ` Ferruh Yigit
2018-01-18 18:10               ` Matan Azrad
2018-01-19 16:19                 ` Ferruh Yigit
2018-01-19 17:35                   ` Ananyev, Konstantin
2018-01-19 17:54                   ` Thomas Monjalon
2018-01-19 18:13                     ` Ferruh Yigit
2018-01-19 18:16                       ` Thomas Monjalon
2018-01-20 19:04                         ` Matan Azrad
2018-01-20 20:28                           ` Thomas Monjalon
2018-01-20 20:45                             ` Matan Azrad
2018-01-21 20:07                   ` Ferruh Yigit
2018-01-18 11:27           ` [dpdk-dev] [PATCH v6 5/6] ethdev: adjust flow " Matan Azrad
2018-01-18 11:27           ` [dpdk-dev] [PATCH v6 6/6] net/failsafe: fix removed device handling Matan Azrad
2018-01-20 21:12           ` [dpdk-dev] [PATCH v7 0/6] Fail-safe\ethdev: fix removal handling lack Matan Azrad
2018-01-20 21:12             ` [dpdk-dev] [PATCH v7 1/6] ethdev: add devop to check removal status Matan Azrad
2018-01-20 21:12             ` [dpdk-dev] [PATCH v7 2/6] net/mlx4: support a device removal check operation Matan Azrad
2018-01-20 21:12             ` [dpdk-dev] [PATCH v7 3/6] net/mlx5: " Matan Azrad
2018-01-20 21:12             ` [dpdk-dev] [PATCH v7 4/6] ethdev: adjust APIs removal error report Matan Azrad
2018-01-20 21:12             ` [dpdk-dev] [PATCH v7 5/6] ethdev: adjust flow " Matan Azrad
2018-01-20 21:12             ` [dpdk-dev] [PATCH v7 6/6] net/failsafe: fix removed device handling Matan Azrad
2018-01-21 20:28             ` [dpdk-dev] [PATCH v7 0/6] Fail-safe\ethdev: fix removal handling lack Ferruh Yigit

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