From: Pascal Mazon <pascal.mazon@6wind.com>
To: dev@dpdk.org
Subject: Re: [dpdk-dev] [PATCH] net/tap: driver closing tx interface on queue setup
Date: Mon, 30 Jan 2017 15:38:10 +0100 [thread overview]
Message-ID: <dfe52108-6bb8-73ba-f65d-0aa066882e48@6wind.com> (raw)
In-Reply-To: <2c430141-94c1-5482-7fc2-94f5908b41e0@intel.com>
On 01/30/2017 12:00 PM, Ferruh Yigit wrote:> On 1/29/2017 2:12 AM, Keith
Wiles wrote:
>> The tap driver setup both rx and tx file descriptors when the
>> rte_eth_rx_queue_setup() causing the tx to be closed when tx setup
>> was called.
>
> Can you please describe the problem more.
> Without this patch rx->fd == tx->fd, with this patch rx and tx has
> different file descriptors.
>
> What was the wrong with rx and tx having same fd?
>
> As far as I can see, rte_eth_rx_queue_setup() won't close tx->fd, that
> function will do nothing if rx or tx has valid fd.
>
>>
>> Signed-off-by: Keith Wiles <keith.wiles@intel.com>
>
> <...>
>
Hi,
The tap PMD recently broke for me because of this patch [1].
During init (eth_dev_tap_create()), the tap PMD allocates a shared RX/TX
queue through tun_alloc().
The recent patch now releases existing queues in rx_queue_setup(),
before adding new ones.
When rx_queue_setup() is called, it uses close() calls on all shared
queues, effectively deleting the netdevice.
That's the main issue here.
I tested Keith's patch [2], and it fixes that issue, using separate queues.
There is however a couple of other queues-related issues in the tap PMD,
but I'm not sure how to address them properly:
1. internals->fds[] gets filled only with RX queues (appart from index 0
that is common to both RX and TX).
It means that RX queues only will be deleted when calling
rte_pmd_tap_remove() or tap_tx_queue_release().
2. tap_dev_stop() is not symmetrical with tap_dev_start(): queues won't
get re-created after a stop.
It may be best to keep the very first fd (created with tun_alloc() in
eth_dev_tap_create() during probe) apart.
And then add separate TX/RX queues in internals->txq[] and
internals->rxq[] respectively.
What do you think?
[1] d00d7cc88335 ("ethdev: release queue before setting up")
[2] http://dpdk.org/ml/archives/dev/2017-January/056470.html
--
Pascal Mazon
www.6wind.com
next prev parent reply other threads:[~2017-01-30 14:39 UTC|newest]
Thread overview: 12+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-29 2:12 Keith Wiles
2017-01-30 11:00 ` Ferruh Yigit
2017-01-30 14:34 ` Wiles, Keith
2017-01-30 17:42 ` Ferruh Yigit
2017-01-30 18:20 ` Wiles, Keith
2017-01-30 19:31 ` Ferruh Yigit
2017-01-30 14:38 ` Pascal Mazon [this message]
2017-01-30 15:04 ` Wiles, Keith
2017-01-30 17:19 ` Ferruh Yigit
2017-01-30 20:54 ` [dpdk-dev] [PATCH v2] net/tap: fix invalid queue file descriptor Ferruh Yigit
2017-01-30 20:57 ` Wiles, Keith
2017-01-30 21:23 ` Ferruh Yigit
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