From nobody Thu Feb 12 01:47:16 2026 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 21AC6C77B60 for ; Sat, 29 Apr 2023 15:48:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231406AbjD2Psu (ORCPT ); Sat, 29 Apr 2023 11:48:50 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:49344 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231249AbjD2Pss (ORCPT ); Sat, 29 Apr 2023 11:48:48 -0400 Received: from mail-pf1-x42a.google.com (mail-pf1-x42a.google.com [IPv6:2607:f8b0:4864:20::42a]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0716D172E for ; Sat, 29 Apr 2023 08:48:23 -0700 (PDT) Received: by mail-pf1-x42a.google.com with SMTP id d2e1a72fcca58-63b4960b015so760462b3a.3 for ; Sat, 29 Apr 2023 08:48:23 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=bytedance.com; s=google; t=1682783302; x=1685375302; h=message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=+9P2mZM7ci2Xw5rF6VxKlkFONlC9SOUfJRYGLbDsm7w=; b=EPryO+NxFUtz9gXpD8UMe0U5isNA42gRV9JOeOHlwB4AGQBAibZPgaE4LOrecks1QL l6wz6P04lHKe6XUTwN/Pkwuil/ZsU3QoZX+gYMOtX7ZGSMuRt4TAwZDHkrCVAEPEK/oh wZDAX7L9z9uxy7K/e66iA62dFXPjPFZUy6bYI1eCHuCEYgPf4VUE5lFazVEYRpYq1lz8 y3yL9gaixAd4XjG3pEFuHOV76sSDkLIUDyxiOxZhgaxOghBTMw1wY1zphhp2Gi0m6qdz Cpca1ksWQcuzs7oDyUYGnYZzvpR7FpHj9yrvoMaCnLeX3JXWcYm2z4Aiwpp5lvaNtqbd OD+Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1682783302; x=1685375302; h=message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=+9P2mZM7ci2Xw5rF6VxKlkFONlC9SOUfJRYGLbDsm7w=; b=d6jUb/TDLo7ib97Tx4hvPLEFfWtymcJd/C/0AMLRDm22XZp7ACdrJBauetF8s+e3a2 ef+UOKjIxXPp0g3zOH60AxvqEE/qZwiN694I6tAlDYE//DIT8QQjE97fWJe+OKMklZrN op2J7AVn2XgfJKksgH8slzAMWV3O68RmCd9GOHOFGnfYyGKeHo0cbDAHIJsr087NS71n 2GuDm/34vyfSz8dHZyEWIFLzxwPn3+9U+J2M/2btFuuNDijjH8hG2iP676fdxaFHw9l+ 25P5zG5rau82AfuIAKqTNUlPctWgRDLYOtG2unm7xisJtB3OGRCjUNDPqqPG2u0VRKXB XL3A== X-Gm-Message-State: AC+VfDybp6Z0EMWHrFoL6NjiCZl8iKpuql+mpBeotfFQjySwj0Y8nnQ8 2Wf+ittgpEl/jF/Ouzm2Tc3Qjw== X-Google-Smtp-Source: ACHHUZ53Fj9h6nZ4V5lFVpFEXCq+C8z+ue/01AyizM4xlHjhyXzWh1UbrK6VxXY1/kvtAHXIsCZDMg== X-Received: by 2002:a05:6a00:1515:b0:640:e12a:3a20 with SMTP id q21-20020a056a00151500b00640e12a3a20mr13492262pfu.1.1682783302499; Sat, 29 Apr 2023 08:48:22 -0700 (PDT) Received: from localhost.localdomain ([2408:8207:2423:d60:94ce:3d97:123:5b2c]) by smtp.gmail.com with ESMTPSA id c17-20020a056a000ad100b005ae02dc5b94sm17170554pfl.219.2023.04.29.08.48.18 (version=TLS1_2 cipher=ECDHE-ECDSA-AES128-GCM-SHA256 bits=128/128); Sat, 29 Apr 2023 08:48:22 -0700 (PDT) From: Wenliang Wang To: mst@redhat.com, jasowang@redhat.com, davem@davemloft.net, edumazet@google.com, kuba@kernel.org, pabeni@redhat.com, zhengqi.arch@bytedance.com, willemdebruijn.kernel@gmail.com Cc: virtualization@lists.linux-foundation.org, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, Wenliang Wang Subject: [PATCH v3] virtio_net: suppress cpu stall when free_unused_bufs Date: Sat, 29 Apr 2023 23:47:58 +0800 Message-Id: <1682783278-12819-1-git-send-email-wangwenliang.1995@bytedance.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" For multi-queue and large ring-size use case, the following error occurred when free_unused_bufs: rcu: INFO: rcu_sched self-detected stall on CPU. Signed-off-by: Wenliang Wang --- v2: -add need_resched check. -apply same logic to sq. v3: -use cond_resched instead. --- drivers/net/virtio_net.c | 2 ++ 1 file changed, 2 insertions(+) diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c index ea1bd4bb326d..744bdc8a1abd 100644 --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -3559,12 +3559,14 @@ static void free_unused_bufs(struct virtnet_info *v= i) struct virtqueue *vq =3D vi->sq[i].vq; while ((buf =3D virtqueue_detach_unused_buf(vq)) !=3D NULL) virtnet_sq_free_unused_buf(vq, buf); + cond_resched(); } =20 for (i =3D 0; i < vi->max_queue_pairs; i++) { struct virtqueue *vq =3D vi->rq[i].vq; while ((buf =3D virtqueue_detach_unused_buf(vq)) !=3D NULL) virtnet_rq_free_unused_buf(vq, buf); + cond_resched(); } } =20 --=20 2.20.1