From patchwork Tue Dec 5 06:48:05 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arseniy Krasnov X-Patchwork-Id: 13479458 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=salutedevices.com header.i=@salutedevices.com header.b="OR6QVcpO" Received: from mx1.sberdevices.ru (mx2.sberdevices.ru [45.89.224.132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 32C18136; Mon, 4 Dec 2023 22:56:33 -0800 (PST) Received: from p-infra-ksmg-sc-msk02 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id F3D85120026; Tue, 5 Dec 2023 09:56:29 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru F3D85120026 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=salutedevices.com; s=mail; t=1701759390; bh=hRb1OWAketAgWsS/ac4IBqv06gfS9pcaRvoWb7Do5Fg=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=OR6QVcpOFCLTZlem67vZ3/D3KJKezBtF2A9wpCNlWLiLi6wokvoI/X5P2y0ZEcnBi bFvOM4bjUqpx1NtSc+ebn2tY6Li8s+w2hBDOvLSp9tJQrXbDg5S6NDwRebGwmD0UwQ 6VaZDjQJ1Ym+vFEA0K/F0uKPqBa+N/gH4oOsoK7SMJ5rBAQK2TLdFlddzzmRjE4K1Y qnNTg7y4PdjQLjm+zHgByCx8OZJk5GKQa2ZQGc+OdRFJOeJQ9gURrFlh5YHZWrs3JP MaFQdXlsIvBhn29eAdLzkmo6YKD8xokEjwOU9NVxdZwuko7pZeBAe4Dw5E4rKfwyeq 1xmxtwgPGuodA== Received: from p-i-exch-sc-m01.sberdevices.ru (p-i-exch-sc-m01.sberdevices.ru [172.16.192.107]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.sberdevices.ru (Postfix) with ESMTPS; Tue, 5 Dec 2023 09:56:29 +0300 (MSK) Received: from localhost.localdomain (100.64.160.123) by p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.1118.40; Tue, 5 Dec 2023 09:56:29 +0300 From: Arseniy Krasnov To: Stefan Hajnoczi , Stefano Garzarella , "David S. Miller" , Eric Dumazet , Jakub Kicinski , Paolo Abeni , "Michael S. Tsirkin" , Jason Wang , Bobby Eshleman CC: , , , , , , Subject: [PATCH net-next v6 3/4] virtio/vsock: fix logic which reduces credit update messages Date: Tue, 5 Dec 2023 09:48:05 +0300 Message-ID: <20231205064806.2851305-4-avkrasnov@salutedevices.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20231205064806.2851305-1-avkrasnov@salutedevices.com> References: <20231205064806.2851305-1-avkrasnov@salutedevices.com> Precedence: bulk X-Mailing-List: kvm@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-ClientProxiedBy: p-i-exch-sc-m02.sberdevices.ru (172.16.192.103) To p-i-exch-sc-m01.sberdevices.ru (172.16.192.107) X-KSMG-Rule-ID: 10 X-KSMG-Message-Action: clean X-KSMG-AntiSpam-Lua-Profiles: 181836 [Dec 05 2023] X-KSMG-AntiSpam-Version: 6.0.0.2 X-KSMG-AntiSpam-Envelope-From: avkrasnov@salutedevices.com X-KSMG-AntiSpam-Rate: 0 X-KSMG-AntiSpam-Status: not_detected X-KSMG-AntiSpam-Method: none X-KSMG-AntiSpam-Auth: dkim=none X-KSMG-AntiSpam-Info: LuaCore: 5 0.3.5 98d108ddd984cca1d7e65e595eac546a62b0144b, {Tracking_from_domain_doesnt_match_to}, salutedevices.com:7.1.1;p-i-exch-sc-m01.sberdevices.ru:7.1.1,5.0.1;100.64.160.123:7.1.2;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1;127.0.0.199:7.1.2, FromAlignment: s, ApMailHostAddress: 100.64.160.123 X-MS-Exchange-Organization-SCL: -1 X-KSMG-AntiSpam-Interceptor-Info: scan successful X-KSMG-AntiPhishing: Clean X-KSMG-LinksScanning: Clean X-KSMG-AntiVirus: Kaspersky Secure Mail Gateway, version 2.0.1.6960, bases: 2023/12/05 03:59:00 #22607474 X-KSMG-AntiVirus-Status: Clean, skipped Add one more condition for sending credit update during dequeue from stream socket: when number of bytes in the rx queue is smaller than SO_RCVLOWAT value of the socket. This is actual for non-default value of SO_RCVLOWAT (e.g. not 1) - idea is to "kick" peer to continue data transmission, because we need at least SO_RCVLOWAT bytes in our rx queue to wake up user for reading data (in corner case it is also possible to stuck both tx and rx sides, this is why 'Fixes' is used). Fixes: b89d882dc9fc ("vsock/virtio: reduce credit update messages") Signed-off-by: Arseniy Krasnov --- net/vmw_vsock/virtio_transport_common.c | 9 +++++++-- 1 file changed, 7 insertions(+), 2 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index e137d740804e..461c89882142 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -558,6 +558,7 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, struct virtio_vsock_sock *vvs = vsk->trans; size_t bytes, total = 0; struct sk_buff *skb; + bool low_rx_bytes; int err = -EFAULT; u32 free_space; @@ -602,6 +603,8 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, } free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt); + low_rx_bytes = (vvs->rx_bytes < + sock_rcvlowat(sk_vsock(vsk), 0, INT_MAX)); spin_unlock_bh(&vvs->rx_lock); @@ -611,9 +614,11 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, * too high causes extra messages. Too low causes transmitter * stalls. As stalls are in theory more expensive than extra * messages, we set the limit to a high value. TODO: experiment - * with different values. + * with different values. Also send credit update message when + * number of bytes in rx queue is not enough to wake up reader. */ - if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE) + if (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE || + low_rx_bytes) virtio_transport_send_credit_update(vsk); return total;