From mboxrd@z Thu Jan 1 00:00:00 1970 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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 D7538C4338F for ; Fri, 30 Jul 2021 10:50:32 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 802B560F9B for ; Fri, 30 Jul 2021 10:50:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 802B560F9B Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linuxfoundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=lists.linux-foundation.org Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 5627560732; Fri, 30 Jul 2021 10:50:32 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id axXx0iKSgqn5; Fri, 30 Jul 2021 10:50:31 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp3.osuosl.org (Postfix) with ESMTPS id A8EB56060A; Fri, 30 Jul 2021 10:50:30 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 760C5C0010; Fri, 30 Jul 2021 10:50:30 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id AD673C000E for ; Fri, 30 Jul 2021 10:50:28 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 99ECC60732 for ; Fri, 30 Jul 2021 10:50:28 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id JXjeeBMe10lk for ; Fri, 30 Jul 2021 10:50:27 +0000 (UTC) X-Greylist: from auto-whitelisted by SQLgrey-1.8.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp3.osuosl.org (Postfix) with ESMTPS id C1DD66060A for ; Fri, 30 Jul 2021 10:50:27 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id C2E0E60FE7; Fri, 30 Jul 2021 10:50:26 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linuxfoundation.org; s=korg; t=1627642227; bh=uwvhp1h+jNLtcu2/e0VGZBLHK4ouCJF0eW8DngsMKtY=; h=Subject:To:Cc:From:Date:From; b=r6dxtrGTyJf1CK0nXfOWmhoOwCG3KVBdBtpqkgO+9uuG8/wH8TsiVi0Wim3KlYQoM r6g+tJEpanCNmZYch4UhSUIPH0uiI5fEIR67RasY0sofBrhtqnMIX9rkdiFBVFj8nl fMMNgSIxwe7lcSzKiTw2E9c2iX32BjNOoEHuvws8= Subject: Patch "virtio_net: Do not pull payload in skb->head" has been added to the 4.14-stable tree To: davem@davemloft.net, edumazet@google.com, gregkh@linuxfoundation.org, jasowang@redhat.com, matthieu.baerts@tessares.net, mst@redhat.com, virtualization@lists.linux-foundation.org, xuanzhuo@linux.alibaba.com From: Date: Fri, 30 Jul 2021 12:50:17 +0200 Message-ID: <1627642217211167@kroah.com> MIME-Version: 1.0 X-stable: commit X-Patchwork-Hint: ignore Cc: stable-commits@vger.kernel.org X-BeenThere: virtualization@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Linux virtualization List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: virtualization-bounces@lists.linux-foundation.org Sender: "Virtualization" This is a note to let you know that I've just added the patch titled virtio_net: Do not pull payload in skb->head to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary The filename of the patch is: virtio_net-do-not-pull-payload-in-skb-head.patch and it can be found in the queue-4.14 subdirectory. If you, or anyone else, feels it should not be added to the stable tree, please let know about it. >From 0f6925b3e8da0dbbb52447ca8a8b42b371aac7db Mon Sep 17 00:00:00 2001 From: Eric Dumazet Date: Fri, 2 Apr 2021 06:26:02 -0700 Subject: virtio_net: Do not pull payload in skb->head From: Eric Dumazet commit 0f6925b3e8da0dbbb52447ca8a8b42b371aac7db upstream. Xuan Zhuo reported that commit 3226b158e67c ("net: avoid 32 x truesize under-estimation for tiny skbs") brought a ~10% performance drop. The reason for the performance drop was that GRO was forced to chain sk_buff (using skb_shinfo(skb)->frag_list), which uses more memory but also cause packet consumers to go over a lot of overhead handling all the tiny skbs. It turns out that virtio_net page_to_skb() has a wrong strategy : It allocates skbs with GOOD_COPY_LEN (128) bytes in skb->head, then copies 128 bytes from the page, before feeding the packet to GRO stack. This was suboptimal before commit 3226b158e67c ("net: avoid 32 x truesize under-estimation for tiny skbs") because GRO was using 2 frags per MSS, meaning we were not packing MSS with 100% efficiency. Fix is to pull only the ethernet header in page_to_skb() Then, we change virtio_net_hdr_to_skb() to pull the missing headers, instead of assuming they were already pulled by callers. This fixes the performance regression, but could also allow virtio_net to accept packets with more than 128bytes of headers. Many thanks to Xuan Zhuo for his report, and his tests/help. Fixes: 3226b158e67c ("net: avoid 32 x truesize under-estimation for tiny skbs") Reported-by: Xuan Zhuo Link: https://www.spinics.net/lists/netdev/msg731397.html Co-Developed-by: Xuan Zhuo Signed-off-by: Xuan Zhuo Signed-off-by: Eric Dumazet Cc: "Michael S. Tsirkin" Cc: Jason Wang Cc: virtualization@lists.linux-foundation.org Acked-by: Jason Wang Signed-off-by: David S. Miller Signed-off-by: Matthieu Baerts Signed-off-by: Greg Kroah-Hartman --- drivers/net/virtio_net.c | 10 +++++++--- include/linux/virtio_net.h | 14 +++++++++----- 2 files changed, 16 insertions(+), 8 deletions(-) --- a/drivers/net/virtio_net.c +++ b/drivers/net/virtio_net.c @@ -339,9 +339,13 @@ static struct sk_buff *page_to_skb(struc offset += hdr_padded_len; p += hdr_padded_len; - copy = len; - if (copy > skb_tailroom(skb)) - copy = skb_tailroom(skb); + /* Copy all frame if it fits skb->head, otherwise + * we let virtio_net_hdr_to_skb() and GRO pull headers as needed. + */ + if (len <= skb_tailroom(skb)) + copy = len; + else + copy = ETH_HLEN; skb_put_data(skb, p, copy); len -= copy; --- a/include/linux/virtio_net.h +++ b/include/linux/virtio_net.h @@ -65,14 +65,18 @@ static inline int virtio_net_hdr_to_skb( skb_reset_mac_header(skb); if (hdr->flags & VIRTIO_NET_HDR_F_NEEDS_CSUM) { - u16 start = __virtio16_to_cpu(little_endian, hdr->csum_start); - u16 off = __virtio16_to_cpu(little_endian, hdr->csum_offset); + u32 start = __virtio16_to_cpu(little_endian, hdr->csum_start); + u32 off = __virtio16_to_cpu(little_endian, hdr->csum_offset); + u32 needed = start + max_t(u32, thlen, off + sizeof(__sum16)); + + if (!pskb_may_pull(skb, needed)) + return -EINVAL; if (!skb_partial_csum_set(skb, start, off)) return -EINVAL; p_off = skb_transport_offset(skb) + thlen; - if (p_off > skb_headlen(skb)) + if (!pskb_may_pull(skb, p_off)) return -EINVAL; } else { /* gso packets without NEEDS_CSUM do not set transport_offset. @@ -100,14 +104,14 @@ retry: } p_off = keys.control.thoff + thlen; - if (p_off > skb_headlen(skb) || + if (!pskb_may_pull(skb, p_off) || keys.basic.ip_proto != ip_proto) return -EINVAL; skb_set_transport_header(skb, keys.control.thoff); } else if (gso_type) { p_off = thlen; - if (p_off > skb_headlen(skb)) + if (!pskb_may_pull(skb, p_off)) return -EINVAL; } } Patches currently in stable-queue which might be from edumazet@google.com are queue-4.14/net-annotate-data-race-around-sk_ll_usec.patch queue-4.14/virtio_net-do-not-pull-payload-in-skb-head.patch queue-4.14/gro-ensure-frag0-meets-ip-header-alignment.patch _______________________________________________ Virtualization mailing list Virtualization@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/virtualization