From: Ferruh Yigit <ferruh.yigit@intel.com>
To: Stephen Hemminger <stephen@networkplumber.org>,
Yuanhan Liu <yliu@fridaylinux.org>,
Maxime Coquelin <maxime.coquelin@redhat.com>
Cc: Andrew Rybchenko <arybchenko@solarflare.com>, dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH v5 00/15] common ethdev linkstatus functions
Date: Fri, 19 Jan 2018 16:35:09 +0000 [thread overview]
Message-ID: <fae9b4fd-6888-88b3-3ec3-b60411c7f60a@intel.com> (raw)
In-Reply-To: <24375588-ec05-9e54-264d-69dcb48f7f16@intel.com>
On 1/17/2018 4:18 PM, Ferruh Yigit wrote:
> On 1/17/2018 4:05 PM, Stephen Hemminger wrote:
>> On Wed, 17 Jan 2018 14:32:17 +0000
>> Ferruh Yigit <ferruh.yigit@intel.com> wrote:
>>
>>> On 1/17/2018 7:56 AM, Andrew Rybchenko wrote:
>>>> On 01/16/2018 09:37 PM, Stephen Hemminger wrote:
>>>>> While reviewing drivers, noticed a lot of unnecessary
>>>>> duplication of code in drivers for handling the eth_dev link status
>>>>> information. While consolidating this, it also became obvious that
>>>>> some drivers behave differently for no good reason.
>>>>>
>>>>> It also was a good chance to introduce atomic exchange primitives
>>>>> in EAL because there are other places using cmpset where not
>>>>> necessary (such as bonding).
>>>>>
>>>>> Mostly only compile tested only, don't have all of the hardware
>>>>> available (except ixgbe and virtio) to test.
>>>>>
>>>>> Note: the eth_dev_link_update function return value is inconsistent
>>>>> across drivers. Should be changed to be void.
>>>>
>>>> I would say "link_update" callback return value is inconsistent across
>>>> drivers. I'm not sure which direction is right here: make it consistent
>>>> or make it void. Also any changes in link information could be
>>>> important. As I understand it should not happen without up/down,
>>>> but bugs with loss of intermediate transitions are definitely possible.
>>>> So, notifying about any changes in link information is definitely safer.
>>>> May be not now.
>>>
>>> Again, why not return previous link status, it is simple enough to prevent
>>> inconsistent usage.
>>>
>>> rte_eth_link_get() already discards the return value, so won't be a problem there.
>>>
>>> For the cases PMD would like know about link changes, they will need to
>>> implement almost same link_update function with a return value, so why not use
>>> existing link_update function?
>>>
>>> Like been in virtio, link_update() used in interrupt handler, and calls a
>>> callback process if status changes. When link_update() return status changed to
>>> void, I guess they will need to implement another version of the link_update
>>> with return and use it.
>>
>> The interrupt and non-interrupt model are different.
>
> Yes. But for virtio specific usage:
>
> virtio_interrupt_handler()
> virtio_dev_link_update() == 0
> _rte_eth_dev_callback_process()
>
> meantime same exact virtio_dev_link_update() used as:
> .link_update = virtio_dev_link_update,
>
> so updating virtio_dev_link_update() to not return status change, will update
> logic in virtio_interrupt_handler(), no?
I would like to see this patch in, because it is useful and almost done. The
concern I mentioned above effects virtio.
Can virtio maintainers check if it is OK to get this as it is please?
>
>> Also the driver internally may want to do something different, this is about
>> the return value for dev_ops->link_update.
>
> Agreed, driver may do something different. And the function needs to be
> implemented will be very close to dev_ops->link_update. I thought making
> dev_ops->link_update more generic can prevent duplication there. And aligns with
> virtio usage..
>
>> The code in rte_eth_dev never
>> used the return value. The bonding driver was expecting it to work but it
>> doesn't.
>
> Agreed.
>
>> Anyway drivers shouldn't in general be directly calling other
>> devices eth_dev_ops
>
> I guess now there are a few overlay PMDs does this.
>
next prev parent reply other threads:[~2018-01-19 16:35 UTC|newest]
Thread overview: 45+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-01-16 18:37 Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 01/15] eal: introduce atomic exchange operation Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 02/15] ethdev: add linkstatus get/set helper functions Stephen Hemminger
2018-01-17 7:49 ` Andrew Rybchenko
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 03/15] net/virtio: use eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 04/15] net/vmxnet3: use rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 05/15] net/dpaa2: " Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 06/15] net/nfp: use rte_eth_linkstatus functions Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 07/15] net/e1000: use rte_eth_linkstatus helpers Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 08/15] net/ixgbe: use rte_eth_linkstatus functions Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 09/15] net/sfc: use new " Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 10/15] net/i40e: use " Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 11/15] net/liquidio: use rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 12/15] net/thunderx: " Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 13/15] net/szedata: use _rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 14/15] net/octeontx: use rte_eth_linkstatus_set Stephen Hemminger
2018-01-16 18:37 ` [dpdk-dev] [PATCH v5 15/15] net/enic: " Stephen Hemminger
2018-01-17 5:19 ` [dpdk-dev] [PATCH v5 00/15] common ethdev linkstatus functions Shreyansh Jain
2018-01-17 7:56 ` Andrew Rybchenko
2018-01-17 14:32 ` Ferruh Yigit
2018-01-17 16:05 ` Stephen Hemminger
2018-01-17 16:18 ` Ferruh Yigit
2018-01-19 16:35 ` Ferruh Yigit [this message]
2018-01-21 18:35 ` Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 01/14] eal: introduce atomic exchange operation Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 02/14] ethdev: add linkstatus get/set helper functions Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 03/14] net/virtio: use ethdev linkstatus " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 04/14] net/vmxnet3: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 05/14] net/dpaa2: " Ferruh Yigit
2018-01-22 12:28 ` Shreyansh Jain
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 06/14] net/nfp: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 07/14] net/e1000: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 08/14] net/ixgbe: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 09/14] net/i40e: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 10/14] net/liquidio: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 11/14] net/thunderx: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 12/14] net/szedata2: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 13/14] net/octeontx: " Ferruh Yigit
2018-01-21 18:59 ` [dpdk-dev] [PATCH v6 14/14] net/enic: " Ferruh Yigit
2018-01-21 19:25 ` [dpdk-dev] [PATCH v6 01/14] eal: introduce atomic exchange operation Ferruh Yigit
2018-01-21 23:50 ` Thomas Monjalon
2018-01-22 16:56 ` Stephen Hemminger
2018-01-22 21:03 ` Thomas Monjalon
2018-01-22 21:48 ` Stephen Hemminger
2018-01-22 22:09 ` Thomas Monjalon
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