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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 55B9BC4332F for ; Wed, 28 Dec 2022 06:31:50 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229549AbiL1Gbt (ORCPT ); Wed, 28 Dec 2022 01:31:49 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:39738 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229526AbiL1Gbs (ORCPT ); Wed, 28 Dec 2022 01:31:48 -0500 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0A96EBC07 for ; Tue, 27 Dec 2022 22:31:02 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1672209062; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=n2KeMAKOxs2dGkktehdaFB5TmuZYls6R2nspxmVS2pc=; b=Pe2sB5FKRGUmtzndp8mNsH34vXUxGHok17AQZgFLQdIheWM9MFT3Ui348Gc4cwFlV7X6wY /PS5mHc52HzUxsH1uauu+hmOGgmVUmxXUBgb57Q+Q0bP8vpgVxqqiLgM6b2EUxDst32D1b 8fXN5ebwi1cC95VzHd+73kf8W4IdhTQ= Received: from mail-pg1-f199.google.com (mail-pg1-f199.google.com [209.85.215.199]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_128_GCM_SHA256) id us-mta-468-OSCKuMy8P2K9ELMv1SOyQw-1; Wed, 28 Dec 2022 01:31:00 -0500 X-MC-Unique: OSCKuMy8P2K9ELMv1SOyQw-1 Received: by mail-pg1-f199.google.com with SMTP id f132-20020a636a8a000000b00473d0b600ebso7655453pgc.14 for ; Tue, 27 Dec 2022 22:30:59 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:in-reply-to:from:references:cc:to :content-language:subject:user-agent:mime-version:date:message-id :x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=n2KeMAKOxs2dGkktehdaFB5TmuZYls6R2nspxmVS2pc=; b=H0Mqxzy1mm/eDlWjxfEnybaEJEBuFZ88h4tKn/SLMi/gx0G59GelhM46z0nH6EVb4e ikF2qkklRIwcQ0RZghyv7v8bTeVYyKEbM3lmQs+1/jLLPFZQuQyRKjE3X4ultaskvYf4 uK/rBIZnvjUUwPP4tKtZkMEXzWge6GycvgbErFMSF0FtrXofPH0x/6nh/lJBHVY1S0M1 6ENXjiEOFtUpjgr199BSjI0g+BQwThcalkyI3kGshxYYpuAQfAdmICI5bdU0NfBsD2K5 ZMkMDnP2ipmsWM7XbIokoIyAWHN5h2vbAH/nhSsU7A87Kw9kHXokxu/UDOzfipDuVzqM DH9A== X-Gm-Message-State: AFqh2ko1uHMuadHWKzxZgsxtJUQSSWRpr639FuHFYaDytnazQp/zq5qs icGNuGuqpc0Wf/ruYkclXy+bqRGFLrpSYflNlDaqHWyFb1XJiPFRKs51HHh3NwHpfDHZjXc4SEQ +1jfNc79GS4jj X-Received: by 2002:aa7:83d1:0:b0:580:d71e:a2e5 with SMTP id j17-20020aa783d1000000b00580d71ea2e5mr13675267pfn.22.1672209059048; Tue, 27 Dec 2022 22:30:59 -0800 (PST) X-Google-Smtp-Source: AMrXdXtz3LablvI6pdqRyz217g39tTPszwJTsdsge+IYn9p6MPtMFBIkxfvLDffbVwiH91mSnroOTQ== X-Received: by 2002:aa7:83d1:0:b0:580:d71e:a2e5 with SMTP id j17-20020aa783d1000000b00580d71ea2e5mr13675258pfn.22.1672209058777; Tue, 27 Dec 2022 22:30:58 -0800 (PST) Received: from [10.72.13.7] ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id b67-20020a621b46000000b0053e38ac0ff4sm9485379pfb.115.2022.12.27.22.30.54 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Tue, 27 Dec 2022 22:30:58 -0800 (PST) Message-ID: Date: Wed, 28 Dec 2022 14:30:52 +0800 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:102.0) Gecko/20100101 Thunderbird/102.6.1 Subject: Re: [PATCH v2 6/9] virtio_net: transmit the multi-buffer xdp Content-Language: en-US To: Heng Qi , netdev@vger.kernel.org, bpf@vger.kernel.org Cc: "Michael S . Tsirkin" , Paolo Abeni , Jakub Kicinski , John Fastabend , "David S . Miller" , Daniel Borkmann , Alexei Starovoitov , Eric Dumazet , Xuan Zhuo References: <20221220141449.115918-1-hengqi@linux.alibaba.com> <20221220141449.115918-7-hengqi@linux.alibaba.com> From: Jason Wang In-Reply-To: Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org 在 2022/12/27 16:26, Heng Qi 写道: > > > 在 2022/12/27 下午3:12, Jason Wang 写道: >> >> 在 2022/12/20 22:14, Heng Qi 写道: >>> This serves as the basis for XDP_TX and XDP_REDIRECT >>> to send a multi-buffer xdp_frame. >>> >>> Signed-off-by: Heng Qi >>> Reviewed-by: Xuan Zhuo >>> --- >>>   drivers/net/virtio_net.c | 27 ++++++++++++++++++++++----- >>>   1 file changed, 22 insertions(+), 5 deletions(-) >>> >>> diff --git a/drivers/net/virtio_net.c b/drivers/net/virtio_net.c >>> index 40bc58fa57f5..9f31bfa7f9a6 100644 >>> --- a/drivers/net/virtio_net.c >>> +++ b/drivers/net/virtio_net.c >>> @@ -563,22 +563,39 @@ static int __virtnet_xdp_xmit_one(struct >>> virtnet_info *vi, >>>                      struct xdp_frame *xdpf) >>>   { >>>       struct virtio_net_hdr_mrg_rxbuf *hdr; >>> -    int err; >>> +    struct skb_shared_info *shinfo; >>> +    u8 nr_frags = 0; >>> +    int err, i; >>>         if (unlikely(xdpf->headroom < vi->hdr_len)) >>>           return -EOVERFLOW; >>>   -    /* Make room for virtqueue hdr (also change xdpf->headroom?) */ >>> +    if (unlikely(xdp_frame_has_frags(xdpf))) { >>> +        shinfo = xdp_get_shared_info_from_frame(xdpf); >>> +        nr_frags = shinfo->nr_frags; >>> +    } >>> + >>> +    /* Need to adjust this to calculate the correct postion >>> +     * for shinfo of the xdpf. >>> +     */ >>> +    xdpf->headroom -= vi->hdr_len; >> >> >> Any reason we need to do this here? (Or if it is, is it only needed >> for multibuffer XDP?) > > Going back to its wrapping function virtnet_xdp_xmit(), we need to > free up the pending old buffers. > If the "is_xdp_frame(ptr)" condition is met, then we need to calculate > the position of skb_shared_info > in xdp_get_frame_len() and xdp_return_frame(), which will involve to > xdpf->data and xdpf->headroom. > Therefore, we need to update the value of headroom synchronously here. Let's tweak the comment above to something like this. With that fixed, Acked-by: Jason Wang Thanks > > Also, it's not necessary for single-buffer xdp, but we need to keep it > because it's harmless and as it should be. > > Thanks. > >> >> Other looks good. >> >> Thanks >> >> >>>       xdpf->data -= vi->hdr_len; >>>       /* Zero header and leave csum up to XDP layers */ >>>       hdr = xdpf->data; >>>       memset(hdr, 0, vi->hdr_len); >>>       xdpf->len   += vi->hdr_len; >>>   -    sg_init_one(sq->sg, xdpf->data, xdpf->len); >>> +    sg_init_table(sq->sg, nr_frags + 1); >>> +    sg_set_buf(sq->sg, xdpf->data, xdpf->len); >>> +    for (i = 0; i < nr_frags; i++) { >>> +        skb_frag_t *frag = &shinfo->frags[i]; >>> + >>> +        sg_set_page(&sq->sg[i + 1], skb_frag_page(frag), >>> +                skb_frag_size(frag), skb_frag_off(frag)); >>> +    } >>>   -    err = virtqueue_add_outbuf(sq->vq, sq->sg, 1, xdp_to_ptr(xdpf), >>> -                   GFP_ATOMIC); >>> +    err = virtqueue_add_outbuf(sq->vq, sq->sg, nr_frags + 1, >>> +                   xdp_to_ptr(xdpf), GFP_ATOMIC); >>>       if (unlikely(err)) >>>           return -ENOSPC; /* Caller handle free/refcnt */ >