DPDK patches and discussions
 help / color / mirror / Atom feed
From: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
To: keith.wiles@intel.com
Cc: dev@dpdk.org, i.maximets@ovn.org, dmarchan@redhat.com,
	Nobuhiro MIKI <nmiki@yahoo-corp.jp>
Subject: [PATCH v2 1/1] net/tap: add a check that Rx/Tx have the same num of queues
Date: Wed, 12 Jan 2022 16:23:24 +0900
Message-ID: <20220112072324.30601-1-nmiki@yahoo-corp.jp> (raw)

Users can create the desired number of RxQ and TxQ in DPDK. For
example, if the number of RxQ = 2 and the number of TxQ = 5,
a total of 8 file descriptors will be created for a tap device,
including RxQ, TxQ, and one for keepalive. The RxQ and TxQ
with the same ID are paired by dup(2).

In this scenario, Kernel will have 3 RxQ where packets are
incoming but not read. The reason for this is that there are only
2 RxQ that are polled by DPDK, while there are 5 queues in Kernel.
This patch add a checking if DPDK has appropriate numbers of
queues to avoid unexpected packet drop.

Signed-off-by: Nobuhiro MIKI <nmiki@yahoo-corp.jp>
---
v2: fix commit message

I had first discussed this issue in OVS [1], but changed my mind
that a fix in DPDK would be more appropriate.
[1]: https://mail.openvswitch.org/pipermail/ovs-dev/2021-November/389690.html
---
 drivers/net/tap/rte_eth_tap.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/tap/rte_eth_tap.c b/drivers/net/tap/rte_eth_tap.c
index 5bb472f1a6..02eb311e09 100644
--- a/drivers/net/tap/rte_eth_tap.c
+++ b/drivers/net/tap/rte_eth_tap.c
@@ -940,6 +940,14 @@ tap_dev_configure(struct rte_eth_dev *dev)
 			RTE_PMD_TAP_MAX_QUEUES);
 		return -1;
 	}
+	if (dev->data->nb_rx_queues != dev->data->nb_tx_queues) {
+		TAP_LOG(ERR,
+			"%s: number of rx queues %d must be equal to number of tx queues %d",
+			dev->device->name,
+			dev->data->nb_rx_queues,
+			dev->data->nb_tx_queues);
+		return -1;
+	}
 
 	TAP_LOG(INFO, "%s: %s: TX configured queues number: %u",
 		dev->device->name, pmd->name, dev->data->nb_tx_queues);
-- 
2.24.4


             reply	other threads:[~2022-01-12  7:23 UTC|newest]

Thread overview: 3+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-01-12  7:23 Nobuhiro MIKI [this message]
2022-01-18 12:31 ` Ferruh Yigit
2022-01-19  7:49   ` Nobuhiro MIKI

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=20220112072324.30601-1-nmiki@yahoo-corp.jp \
    --to=nmiki@yahoo-corp.jp \
    --cc=dev@dpdk.org \
    --cc=dmarchan@redhat.com \
    --cc=i.maximets@ovn.org \
    --cc=keith.wiles@intel.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link

DPDK patches and discussions

This inbox may be cloned and mirrored by anyone:

	git clone --mirror https://inbox.dpdk.org/dev/0 dev/git/0.git

	# If you have public-inbox 1.1+ installed, you may
	# initialize and index your mirror using the following commands:
	public-inbox-init -V2 dev dev/ https://inbox.dpdk.org/dev \
		dev@dpdk.org
	public-inbox-index dev

Example config snippet for mirrors.
Newsgroup available over NNTP:
	nntp://inbox.dpdk.org/inbox.dpdk.dev


AGPL code for this site: git clone https://public-inbox.org/public-inbox.git