From patchwork Thu Dec 14 12:52:28 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Arseniy Krasnov X-Patchwork-Id: 13493019 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (2048-bit key) header.d=salutedevices.com header.i=@salutedevices.com header.b="suq9d+3T" Received: from mx1.sberdevices.ru (mx2.sberdevices.ru [45.89.224.132]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id D1828113; Thu, 14 Dec 2023 05:01:05 -0800 (PST) Received: from p-infra-ksmg-sc-msk02 (localhost [127.0.0.1]) by mx1.sberdevices.ru (Postfix) with ESMTP id 60927120063; Thu, 14 Dec 2023 16:01:04 +0300 (MSK) DKIM-Filter: OpenDKIM Filter v2.11.0 mx1.sberdevices.ru 60927120063 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=salutedevices.com; s=mail; t=1702558864; bh=zcEvNIjBsCBhtUr7ZdFOfNL0OnIE9Ua1XraGXth61Iw=; h=From:To:Subject:Date:Message-ID:MIME-Version:Content-Type:From; b=suq9d+3T+vu2qupzd3S9pUXHViosFY8RiD/ZwHImE7yngpoAdgPAxzpUqoSqD1DQ4 w+VadMts8A6KXd3ZKPD4Lri79WYR4pgAsugLPIUXcy9n6v9yNGsTXp0lZuDeBHxKc3 z8UhlToN1kBASpt34pfjlk25iiGiPJ0r5GeY2pWGAMQGF3tFt3YQS09bhToKHCfQ+n aL2n1bQau94ZFBdYMopMz2L3b8Tsn1r4JDV16zwpljpYuciW/6pfOeYyYNqPtnwnBc +/YI2t1S5zOQZmJen34NrJPVEMTAyZLor9ejoY3qYNe4rZCEglSlNzuB6iWblu8gLI w9aAeVzBnqxJQ== Received: from smtp.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; Thu, 14 Dec 2023 16:01:04 +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; Thu, 14 Dec 2023 16:01:03 +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 v10 1/3] virtio/vsock: fix logic which reduces credit update messages Date: Thu, 14 Dec 2023 15:52:28 +0300 Message-ID: <20231214125230.737764-2-avkrasnov@salutedevices.com> X-Mailer: git-send-email 2.35.0 In-Reply-To: <20231214125230.737764-1-avkrasnov@salutedevices.com> References: <20231214125230.737764-1-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: 182113 [Dec 14 2023] X-KSMG-AntiSpam-Version: 6.1.0.3 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: 7 0.3.7 6d6bf5bd8eea7373134f756a2fd73e9456bb7d1a, {Tracking_from_domain_doesnt_match_to}, smtp.sberdevices.ru:5.0.1,7.1.1;100.64.160.123:7.1.2;salutedevices.com:7.1.1;127.0.0.199:7.1.2;d41d8cd98f00b204e9800998ecf8427e.com:7.1.1, 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: 2023/12/14 10:50:00 #22693095 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 Reviewed-by: Stefano Garzarella Acked-by: Michael S. Tsirkin --- Changelog: v6 -> v7: * Handle wrap of 'fwd_cnt'. * Do to send credit update when 'fwd_cnt' == 'last_fwd_cnt'. v7 -> v8: * Remove unneeded/wrong handling of wrap for 'fwd_cnt'. net/vmw_vsock/virtio_transport_common.c | 13 ++++++++++--- 1 file changed, 10 insertions(+), 3 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index c8e162c9d1df..7eabe5219ef7 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -557,6 +557,8 @@ 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; + u32 fwd_cnt_delta; + bool low_rx_bytes; int err = -EFAULT; u32 free_space; @@ -600,7 +602,10 @@ virtio_transport_stream_do_dequeue(struct vsock_sock *vsk, } } - free_space = vvs->buf_alloc - (vvs->fwd_cnt - vvs->last_fwd_cnt); + fwd_cnt_delta = vvs->fwd_cnt - vvs->last_fwd_cnt; + free_space = vvs->buf_alloc - fwd_cnt_delta; + low_rx_bytes = (vvs->rx_bytes < + sock_rcvlowat(sk_vsock(vsk), 0, INT_MAX)); spin_unlock_bh(&vvs->rx_lock); @@ -610,9 +615,11 @@ 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 (fwd_cnt_delta && + (free_space < VIRTIO_VSOCK_MAX_PKT_BUF_SIZE || low_rx_bytes)) virtio_transport_send_credit_update(vsk); return total;