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([2001:ee0:4f0f:b1d0:aab1:76d6:d5d9:2ab0]) by smtp.gmail.com with ESMTPSA id d9443c01a7336-2ae3d1b2c51sm4794775ad.19.2026.02.27.21.03.37 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 27 Feb 2026 21:03:42 -0800 (PST) Message-ID: <43b3b8dc-bc99-497a-a845-a9697c126d3f@gmail.com> Date: Sat, 28 Feb 2026 12:03:31 +0700 Precedence: bulk X-Mailing-List: netdev@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH net-next] virtio-net: xsk: Support wakeup on RX side To: Jason Xing Cc: netdev@vger.kernel.org, "Michael S. Tsirkin" , Jason Wang , Xuan Zhuo , =?UTF-8?Q?Eugenio_P=C3=A9rez?= , Andrew Lunn , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , virtualization@lists.linux.dev, linux-kernel@vger.kernel.org References: <20260227150949.13089-1-minhquangbui99@gmail.com> Content-Language: en-US From: Bui Quang Minh In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Hi Jason, On 2/28/26 10:49, Jason Xing wrote: > Hi Bui, > > On Fri, Feb 27, 2026 at 11:20 PM Bui Quang Minh > wrote: >> When XDP_USE_NEED_WAKEUP is used and the fill ring is empty so no buffer >> is allocated on RX side, allow RX NAPI to be descheduled. This avoids >> wasting CPU cycles on polling. Users will be notified and they need to >> make a wakeup call after refilling the ring. >> >> Signed-off-by: Bui Quang Minh >> --- >> drivers/net/virtio_net.c | 38 ++++++++++++++++++++++++++++++-------- >> 1 file changed, 30 insertions(+), 8 deletions(-) >> >> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >> index db88dcaefb20..494acc904b2c 100644 >> --- a/drivers/net/virtio_net.c >> +++ b/drivers/net/virtio_net.c >> @@ -1454,8 +1454,19 @@ static int virtnet_add_recvbuf_xsk(struct virtnet_info *vi, struct receive_queue >> xsk_buffs = rq->xsk_buffs; >> >> num = xsk_buff_alloc_batch(pool, xsk_buffs, rq->vq->num_free); >> - if (!num) >> + if (!num) { >> + if (xsk_uses_need_wakeup(pool)) { >> + xsk_set_rx_need_wakeup(pool); >> + /* Return 0 instead of -ENOMEM so that NAPI is >> + * descheduled. >> + */ >> + return 0; >> + } >> + >> return -ENOMEM; >> + } else { >> + xsk_clear_rx_need_wakeup(pool); >> + } >> >> len = xsk_pool_get_rx_frame_size(pool) + vi->hdr_len; >> >> @@ -1588,20 +1599,21 @@ static bool virtnet_xsk_xmit(struct send_queue *sq, struct xsk_buff_pool *pool, >> return sent; >> } >> >> -static void xsk_wakeup(struct send_queue *sq) >> +static void xsk_wakeup(struct napi_struct *napi, struct virtqueue *vq) >> { >> - if (napi_if_scheduled_mark_missed(&sq->napi)) >> + if (napi_if_scheduled_mark_missed(napi)) >> return; >> >> local_bh_disable(); >> - virtqueue_napi_schedule(&sq->napi, sq->vq); >> + virtqueue_napi_schedule(napi, vq); >> local_bh_enable(); >> } >> >> static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag) >> { >> struct virtnet_info *vi = netdev_priv(dev); >> - struct send_queue *sq; >> + struct napi_struct *napi; >> + struct virtqueue *vq; >> >> if (!netif_running(dev)) >> return -ENETDOWN; >> @@ -1609,9 +1621,19 @@ static int virtnet_xsk_wakeup(struct net_device *dev, u32 qid, u32 flag) >> if (qid >= vi->curr_queue_pairs) >> return -EINVAL; >> >> - sq = &vi->sq[qid]; >> + if (flag == XDP_WAKEUP_TX) { > Better use &? Sorry, I don't get your point. Can you elaborate more? Thanks, Quang Minh.