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From: Thomas Monjalon <thomas@monjalon.net>
To: Ferruh Yigit <ferruh.yigit@intel.com>
Cc: dev@dpdk.org, Matan Azrad <matan@mellanox.com>,
	Adrien Mazarguil <adrien.mazarguil@6wind.com>,
	Gaetan Rivet <gaetan.rivet@6wind.com>,
	Andrew Rybchenko <arybchenko@solarflare.com>,
	"Ananyev, Konstantin" <konstantin.ananyev@intel.com>,
	Alejandro Lucero <alejandro.lucero@netronome.com>,
	Jerin Jacob <jerin.jacob@caviumnetworks.com>,
	Hemant Agrawal <hemant.agrawal@nxp.com>,
	Shahaf Shuler <shahafs@mellanox.com>,
	Olivier MATZ <olivier.matz@6wind.com>,
	"Zhang, Helin" <helin.zhang@intel.com>
Subject: Re: [dpdk-dev] [PATCH v6 4/6] ethdev: adjust APIs removal error report
Date: Fri, 19 Jan 2018 19:16:55 +0100	[thread overview]
Message-ID: <3230393.d19WHEAjBn@xps> (raw)
In-Reply-To: <7d77f38b-1259-d4b8-9d19-a21d80de9c04@intel.com>

19/01/2018 19:13, Ferruh Yigit:
> On 1/19/2018 5:54 PM, Thomas Monjalon wrote:
> > 19/01/2018 17:19, Ferruh Yigit:
> >> On 1/18/2018 6:10 PM, Matan Azrad wrote:
> >>> From: Ferruh Yigit, Thursday, January 18, 2018 7:31 PM
> >>>> This patch updates *all* ethdev public APIs to add if device is removed
> >>>> check?
> >>>
> >>> Yes.
> >>>
> >>>> And each check goes to ethdev is_removed() dev_ops to ask if dev is
> >>>> removed.
> >>> Probably, if the REMOVED state setted in will not call device is_remove.
> >>>
> >>>> These must be better way of doing this, am I missing something.
> >>>
> >>> Suggest.
> >>
> >> With a silly analogy, this is like a blind person asking each time if he is dead
> >> before talking to other person.
> >>
> >> At first glance I can think of a kind of watchdog timer can be implemented in
> >> ethdev layer. It provides periodic checks and if device is dead it calls the
> >> registered user callback function.
> >>
> >> This method presented as synchronous method but not triggered from side where
> >> event happens, I mean not triggered from PMD but from application.
> >> So does application doing polling continuously if device is dead?
> >> Or if application is relying this patch to add a check in each API, what happens
> >> if device removed during data processing, will app rely on asynchronous method?
> > 
> > We cannot put a mutex on hardware removal :)
> > So we have to live with errors du to removal.
> > If we are trying to configure a removed device,
> > the error will be not related to the root cause.
> > This patch is just trying to improve the situation by returning
> > an appropriate error code if removal can be detected.
> > Note: the check is run only if there is an error
> > and if the removal is not already detected.
> > 
> > If I understand well, you prefer relying only on asynchronous
> > hotplug events? Even if they come really late?
> 
> I think asynchronous hotplug events are better approach, but if they are late I
> understand you need a solution.
> 
> I assume issue is when device is removed, application can make API calls until
> it detects the removal.
> 
> For that case what do you think instead of ethdev abstraction layer doing a
> translation, define a specific error type and return it from PMDs to indicate
> that error is related to the missing device and application will know device is
> no more there? And consistently use that error type in all PMDs.

Yes it is also a good solution.
I think Matan proposed to integrate it in ethdev to avoid duplicating
the same mechanism in every PMDs.

> Or what do you think above suggested flexible watchdog timer implementation in
> ethdev, so applications may be informed about missing device faster.

I think the watchdog would compete with hotplug events.
So I prefer not integrating one more asynchronous mechanism
for the same purpose.
If we want polling, it can be an option to enable in EAL hotplug.

  reply	other threads:[~2018-01-19 18:17 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
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 [this message]
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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