From: Ferruh Yigit <ferruh.yigit@amd.com>
To: Alan Elder <alan.elder@microsoft.com>,
Long Li <longli@microsoft.com>,
Andrew Rybchenko <andrew.rybchenko@oktetlabs.ru>
Cc: "dev@dpdk.org" <dev@dpdk.org>, stephen <stephen@networkplumber.org>
Subject: Re: [PATCH v4] net/netvsc: fix number Tx queues > Rx queues
Date: Mon, 15 Apr 2024 19:11:24 +0100 [thread overview]
Message-ID: <2db62108-c655-4e00-8cf6-045a98f7d37e@amd.com> (raw)
In-Reply-To: <PA4PR83MB05261AB024A2F6A286CBF22E97092@PA4PR83MB0526.EURPRD83.prod.outlook.com>
On 4/15/2024 3:40 PM, Alan Elder wrote:
> The previous code allowed the number of Tx queues to be set higher than the number of Rx queues. If a packet was sent on a Tx queue with index
>> = number Rx queues there was a segfault due to accessing beyond the end of the dev->data->rx_queues[] array.
>
> #0 rte_spinlock_trylock (sl = invalid address) at /include/rte_spinlock.h L63
> #1 hn_process_events at /drivers/net/netvsc/hn_rxtx.c L 1129
> #2 hn_xmit_pkts at /drivers/net/netvsc/hn_rxtx.c L1553
>
> This commit fixes the issue by creating an Rx queue for every Tx queue meaning that an event buffer is allocated to handle receiving Tx completion messages.
>
> mbuf pool and Rx ring are not allocated for these additional Rx queues and RSS configuration ensures that no packets are received on them.
>
> Fixes: 4e9c73e96e83 ("net/netvsc: add Hyper-V network device")
> Cc: sthemmin@microsoft.com
> Cc: stable@dpdk.org
>
> Signed-off-by: Alan Elder <alan.elder@microsoft.com>
<...>
> @@ -552,10 +595,12 @@ static void hn_rxpkt(struct hn_rx_queue *rxq, struct hn_rx_bufinfo *rxb,
> const struct hn_rxinfo *info)
> {
> struct hn_data *hv = rxq->hv;
> - struct rte_mbuf *m;
> + struct rte_mbuf *m = NULL;
> bool use_extbuf = false;
>
> - m = rte_pktmbuf_alloc(rxq->mb_pool);
> + if (likely(rxq->mb_pool != NULL))
> + m = rte_pktmbuf_alloc(rxq->mb_pool);
> +
>
This introduced additional check in Rx path, not sure what is the
performance impact.
I can see Long already acked the v3, I just want to double check.
If Tx queue number > Rx queue number is not a common usecase, perhaps it
can be an option to forbid it instead of getting performance hit.
Or it can be possible to have a dedicated Rx queue, like queue_id 0, for
Tx completion events for Tx queue_id > Rx queue number, etc..
But Long if you prefer to continue with this patch, please ack it and I
can continue with it.
next prev parent reply other threads:[~2024-04-15 18:11 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2024-02-29 19:29 [PATCH] " Alan Elder
2024-02-29 21:53 ` Stephen Hemminger
2024-03-01 2:03 ` Long Li
2024-03-08 18:21 ` Alan Elder
2024-03-08 18:09 ` [PATCH v2] " Alan Elder
2024-03-11 22:31 ` Ferruh Yigit
2024-03-12 19:08 ` Long Li
2024-03-19 14:16 ` [PATCH v3] " Alan Elder
2024-03-19 18:40 ` Long Li
2024-04-11 11:38 ` Ferruh Yigit
2024-04-11 20:45 ` [EXTERNAL] " Alan Elder
2024-04-12 10:23 ` Ferruh Yigit
2024-04-12 16:50 ` Alan Elder
2024-04-15 17:54 ` Ferruh Yigit
2024-04-15 14:40 ` [PATCH v4] " Alan Elder
2024-04-15 18:11 ` Ferruh Yigit [this message]
2024-04-17 23:45 ` Long Li
2024-05-01 7:43 ` Morten Brørup
2024-03-19 14:19 ` [PATCH v2] " Alan Elder
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