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From: Thomas Monjalon <thomas@monjalon.net>
To: Bill Zhou <dongz@mellanox.com>, Ferruh Yigit <ferruh.yigit@intel.com>
Cc: Ori Kam <orika@mellanox.com>, Matan Azrad <matan@mellanox.com>,
	"wenzhuo.lu@intel.com" <wenzhuo.lu@intel.com>,
	"jingjing.wu@intel.com" <jingjing.wu@intel.com>,
	"bernard.iremonger@intel.com" <bernard.iremonger@intel.com>,
	"john.mcnamara@intel.com" <john.mcnamara@intel.com>,
	"marko.kovacevic@intel.com" <marko.kovacevic@intel.com>,
	"arybchenko@solarflare.com" <arybchenko@solarflare.com>,
	dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v2] ethdev: support flow aging
Date: Tue, 21 Apr 2020 12:09:49 +0200	[thread overview]
Message-ID: <21747191.6Emhk5qWAg@thomas> (raw)
In-Reply-To: <d51006c6-20d6-c172-36fb-6254cb6a6044@intel.com>

21/04/2020 12:04, Ferruh Yigit:
> On 4/20/2020 5:10 PM, Thomas Monjalon wrote:
> > 20/04/2020 16:06, Ferruh Yigit:
> >> On 4/18/2020 10:44 AM, Thomas Monjalon wrote:
> >>> 18/04/2020 07:04, Bill Zhou:
> >>>> From: Ferruh Yigit <ferruh.yigit@intel.com>
> >>>>> On 4/14/2020 9:32 AM, Dong Zhou wrote:
> >>>>>> --- a/lib/librte_ethdev/rte_ethdev.h
> >>>>>> +++ b/lib/librte_ethdev/rte_ethdev.h
> >>>>>> @@ -3015,6 +3015,7 @@ enum rte_eth_event_type {
> >>>>>>  	RTE_ETH_EVENT_NEW,      /**< port is probed */
> >>>>>>  	RTE_ETH_EVENT_DESTROY,  /**< port is released */
> >>>>>>  	RTE_ETH_EVENT_IPSEC,    /**< IPsec offload related event */
> >>>>>> +	RTE_ETH_EVENT_FLOW_AGED,/**< New aged-out flows is detected
> >>>>> */
> >>>>>>  	RTE_ETH_EVENT_MAX       /**< max value of this enum */
> >>>>>>  };
> >>>>>
> >>>>>
> >>>>> Just recognized that this is failing in ABI check [1], as far as last time for a
> >>>>> similar enum warning a QAT patch has been dropped, should this need to
> >>>>> wait for
> >>>>> 20.11 too?
> >>>>
> >>>> This patch is commonly used for flow aging, there are 2 other patches have 
> >>>> implement flow aging in mlx5 driver reply to this patch.
> > [...]
> >>> These MAX values in enums are a pain.
> >>> We can try to think what can be done, waiting 20.11.
> >>> Not sure there is a solution, except hijacking an existing value
> >>> not used in the PMD, waiting the definitive value in 20.11...
> >>
> >> Dropping from the tree as of now, to not cause more merge conflicts, we can add
> >> it later when issue is resolved.
> > 
> > Thanks for dropping, that's the right thing to do
> > when a patch is breaking ABI check.
> > 
> > After some thoughts, I think it is acceptable to make a v3
> > which ignore this specific enum change. I explain my thought below:
> > 
> > An enum can accept a new value at 2 conditions:
> > 	- added as last value (not changing old values)
> > 	- new value not used by existing API
> > 
> > The value RTE_ETH_EVENT_FLOW_AGED meet the above 2 conditions:
> > 	- only RTE_ETH_EVENT_MAX is changed, which is consistent
> > 	- new value sent to the app only if the app registered for it
> > 
> 
> Same here, as far as I can see it is safe to get this change.
> 
> If any DPDK API returns this enum, either as return of the API or as output
> parameter, this still can be problem, because application may use that returned
> value, this was the concern in the QAT sample.
> 
> But here application registers an event and DPDK library process callback for
> it, so application callbacks won't be called for anything that application
> doesn't already know about, in that respect this should be safe for old
> applications.
> 
> Not sure if we can generalize above two conditions for all enum changes, but we
> can investigate them case by case as we get the warnings.
> 
> > So, except if I miss something, I suggest we add this exception:
> > Allow new value in rte_eth_event_type if added just before RTE_ETH_EVENT_MAX.
> > In other words, allow changing the value of RTE_ETH_EVENT_MAX.
> > The file to add such exception is devtools/libabigail.abignore.
> > 
> 
> OK to exception.

v3 was sent.
I hope we'll get a v4 with justification for the exception.




  reply	other threads:[~2020-04-21 10:09 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-05-26 10:18 [dpdk-dev] [PATCH] [RFC] " Matan Azrad
2019-06-06 10:24 ` Jerin Jacob Kollanukkaran
2019-06-06 10:51   ` Matan Azrad
2019-06-06 12:15     ` Jerin Jacob Kollanukkaran
2019-06-18  5:56       ` Matan Azrad
2019-06-24  6:26         ` Jerin Jacob Kollanukkaran
2019-06-27  8:26           ` Matan Azrad
2020-03-16 16:13       ` Stephen Hemminger
2020-03-16 10:22 ` [dpdk-dev] [PATCH v2] " BillZhou
2020-03-16 12:52 ` BillZhou
2020-03-20  6:59   ` Jerin Jacob
2020-03-24 10:18   ` Andrew Rybchenko
2020-04-10  9:46   ` [dpdk-dev] [PATCH] " BillZhou
2020-04-10 10:14     ` Thomas Monjalon
2020-04-13  4:02       ` Bill Zhou
2020-04-10 12:07     ` Andrew Rybchenko
2020-04-10 12:41       ` Jerin Jacob
2020-04-12  9:13     ` Ori Kam
2020-04-12  9:48       ` Matan Azrad
2020-04-14  8:32     ` [dpdk-dev] [PATCH v2] " Dong Zhou
2020-04-14  8:49       ` Ori Kam
2020-04-14  9:23         ` Bill Zhou
2020-04-16 13:32         ` Ferruh Yigit
2020-04-17 22:00       ` Ferruh Yigit
2020-04-17 22:07         ` Stephen Hemminger
2020-04-18  5:04         ` Bill Zhou
2020-04-18  9:44           ` Thomas Monjalon
2020-04-20 14:06             ` Ferruh Yigit
2020-04-20 16:10               ` Thomas Monjalon
2020-04-21 10:04                 ` Ferruh Yigit
2020-04-21 10:09                   ` Thomas Monjalon [this message]
2020-04-21 15:59                   ` Andrew Rybchenko
2020-04-21  6:22       ` [dpdk-dev] [PATCH v3] " Bill Zhou
2020-04-21 10:11         ` [dpdk-dev] [PATCH v4] " Bill Zhou
2020-04-21 17:13           ` Ferruh Yigit
2020-04-29 14:50           ` Tom Barbette
2020-04-30  7:36             ` Matan Azrad
2020-04-30  7:49               ` Tom Barbette
2020-04-13 14:53   ` [dpdk-dev] [PATCH 0/2] " Dong Zhou
2020-04-13 14:53     ` [dpdk-dev] [PATCH 1/2] net/mlx5: modify ext-counter memory allocation Dong Zhou
2020-04-13 14:53     ` [dpdk-dev] [PATCH 2/2] net/mlx5: support flow aging Dong Zhou
2020-04-24 10:45     ` [dpdk-dev] [PATCH v2 0/2] " Bill Zhou
2020-04-24 10:45       ` [dpdk-dev] [PATCH v2 1/2] net/mlx5: modify ext-counter memory allocation Bill Zhou
2020-04-24 10:45       ` [dpdk-dev] [PATCH v2 2/2] net/mlx5: support flow aging Bill Zhou
2020-04-26  7:07         ` Suanming Mou
2020-04-29  2:25       ` [dpdk-dev] [PATCH v3 0/2] " Bill Zhou
2020-04-29  2:25         ` [dpdk-dev] [PATCH v3 1/2] net/mlx5: modify ext-counter memory allocation Bill Zhou
2020-04-29  2:25         ` [dpdk-dev] [PATCH v3 2/2] net/mlx5: support flow aging Bill Zhou
2020-05-03  7:41         ` [dpdk-dev] [PATCH v3 0/2] " Matan Azrad
2020-05-03 11:47           ` Raslan Darawsheh

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