From patchwork Wed Dec 9 11:48:24 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: wangyunjian X-Patchwork-Id: 341749 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-16.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI, SPF_HELO_NONE, SPF_PASS, URIBL_BLOCKED, USER_AGENT_GIT autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id D1F89C2BB9A for ; Wed, 9 Dec 2020 11:49:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 9B0C52054F for ; Wed, 9 Dec 2020 11:49:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730946AbgLILt1 (ORCPT ); Wed, 9 Dec 2020 06:49:27 -0500 Received: from szxga06-in.huawei.com ([45.249.212.32]:8971 "EHLO szxga06-in.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729260AbgLILt1 (ORCPT ); Wed, 9 Dec 2020 06:49:27 -0500 Received: from DGGEMS411-HUB.china.huawei.com (unknown [172.30.72.59]) by szxga06-in.huawei.com (SkyGuard) with ESMTP id 4Crb0H31f3zhpd9; Wed, 9 Dec 2020 19:48:15 +0800 (CST) Received: from localhost (10.174.243.127) by DGGEMS411-HUB.china.huawei.com (10.3.19.211) with Microsoft SMTP Server id 14.3.487.0; Wed, 9 Dec 2020 19:48:30 +0800 From: wangyunjian To: , CC: , , , , , Yunjian Wang Subject: [PATCH net] vhost_net: fix high cpu load when sendmsg fails Date: Wed, 9 Dec 2020 19:48:24 +0800 Message-ID: <1607514504-20956-1-git-send-email-wangyunjian@huawei.com> X-Mailer: git-send-email 1.9.5.msysgit.1 MIME-Version: 1.0 X-Originating-IP: [10.174.243.127] X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Yunjian Wang Currently we break the loop and wake up the vhost_worker when sendmsg fails. When the worker wakes up again, we'll meet the same error. This will cause high CPU load. To fix this issue, we can skip this description by ignoring the error. Signed-off-by: Yunjian Wang --- drivers/vhost/net.c | 24 +++++------------------- 1 file changed, 5 insertions(+), 19 deletions(-) diff --git a/drivers/vhost/net.c b/drivers/vhost/net.c index 531a00d703cd..ac950b1120f5 100644 --- a/drivers/vhost/net.c +++ b/drivers/vhost/net.c @@ -829,14 +829,8 @@ static void handle_tx_copy(struct vhost_net *net, struct socket *sock) /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(sock, &msg, len); - if (unlikely(err < 0)) { - vhost_discard_vq_desc(vq, 1); - vhost_net_enable_vq(net, vq); - break; - } - if (err != len) - pr_debug("Truncated TX packet: len %d != %zd\n", - err, len); + if (unlikely(err < 0 || err != len)) + vq_err(vq, "Fail to sending packets err : %d, len : %zd\n", err, len); done: vq->heads[nvq->done_idx].id = cpu_to_vhost32(vq, head); vq->heads[nvq->done_idx].len = 0; @@ -925,19 +919,11 @@ static void handle_tx_zerocopy(struct vhost_net *net, struct socket *sock) /* TODO: Check specific error and bomb out unless ENOBUFS? */ err = sock->ops->sendmsg(sock, &msg, len); - if (unlikely(err < 0)) { - if (zcopy_used) { + if (unlikely(err < 0 || err != len)) { + if (zcopy_used && err < 0) vhost_net_ubuf_put(ubufs); - nvq->upend_idx = ((unsigned)nvq->upend_idx - 1) - % UIO_MAXIOV; - } - vhost_discard_vq_desc(vq, 1); - vhost_net_enable_vq(net, vq); - break; + vq_err(vq, "Fail to sending packets err : %d, len : %zd\n", err, len); } - if (err != len) - pr_debug("Truncated TX packet: " - " len %d != %zd\n", err, len); if (!zcopy_used) vhost_add_used_and_signal(&net->dev, vq, head, 0); else