From patchwork Thu Mar 25 09:27:30 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Hangbin Liu X-Patchwork-Id: 12163605 X-Patchwork-Delegate: bpf@iogearbox.net 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=-15.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 D981EC433E1 for ; Thu, 25 Mar 2021 09:28:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 940C861963 for ; Thu, 25 Mar 2021 09:28:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229873AbhCYJ16 (ORCPT ); Thu, 25 Mar 2021 05:27:58 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:41932 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229812AbhCYJ1z (ORCPT ); Thu, 25 Mar 2021 05:27:55 -0400 Received: from mail-pf1-x429.google.com (mail-pf1-x429.google.com [IPv6:2607:f8b0:4864:20::429]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id DC8AFC06174A; Thu, 25 Mar 2021 02:27:54 -0700 (PDT) Received: by mail-pf1-x429.google.com with SMTP id m11so1408550pfc.11; Thu, 25 Mar 2021 02:27:54 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=0scZyiz/gtiHt/zAu/NaA/mr+b5K5YwwUAzLiT9Ya60=; b=T9XnUwZdE52I7IbrnkvlmGM+iim5NjFs4VPM6LPjHvtItyJqIvwkanV4vjKikLRq04 lP91jPYq790SR/MSCj1DhudoFl9vOHpuTG6jQu81UEEeRhxKcUDwbAJ9ZWPnaoJ5eJZ0 sDuSjsJVnKuKZ8EL9/bY+Ltjj3g7Mwj8vFrtbwCRKhcU+cBzn4nCXk4akjF2STDqO5Q6 huvUasGXCXS1YAtAZSJXCTLSjVTvsvLhtIk1vlebFbFnT0EFQUKxRqSSWoXjqpXKHOi/ SCS9x10mYmuU3n5gx5FWSSzrZvLLk/Z4BdeNHwbzurhTh836dks9XS+MP8llTzKcy7Qp eeqg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=0scZyiz/gtiHt/zAu/NaA/mr+b5K5YwwUAzLiT9Ya60=; b=NVCU+7QrFdaQeNy98eIjH8o5p2OhMCrnLsgcjTmwdmo+oBaJgznau4ZO5KjGh6c7Cq 6rhfPJly0xgB1WQZiXTRMwKZt7Q+qhM8xopluUf6x+UPj0an6ZQz94PcM/VqeejK1dID 788bwtusVgr2k0Qvaz+iIp3F1uJb5XwEeOjJiHM55tu+60eYkzPS1z+PY1bTEiEZwOGB 8+mqcW9hF6+p05h+/QxRkeMQqvDi1TN7x/nMu4DYBl30NxmFILCekSUJo0tKfP9duBO/ KKigk40Kgtn5sH/IJMOA0OVVG/6zHCwB9+ZsPWy9toANO7c644vk2mHlzdiAvWjVsXIm KRNQ== X-Gm-Message-State: AOAM531J0wFAusHpfQIEgCN/4cGVHIEmZ+MBa2SZ/C8PHMklW/rssEfT zVTsil12NJBNve+vxNqs5trE9nrCf08= X-Google-Smtp-Source: ABdhPJwyPqiV/8eAcXoITA67VhX/wKn5GSOaaZDXtdJg4Cc14Z3sDL6q/a+PSNj1W3We8RsmLOZM9A== X-Received: by 2002:a17:902:8685:b029:e6:5ff6:f7df with SMTP id g5-20020a1709028685b02900e65ff6f7dfmr8571374plo.40.1616664474215; Thu, 25 Mar 2021 02:27:54 -0700 (PDT) Received: from Leo-laptop-t470s.redhat.com ([209.132.188.80]) by smtp.gmail.com with ESMTPSA id e65sm5191037pfe.9.2021.03.25.02.27.49 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Thu, 25 Mar 2021 02:27:53 -0700 (PDT) From: Hangbin Liu To: bpf@vger.kernel.org Cc: netdev@vger.kernel.org, =?utf-8?q?Toke_H=C3=B8iland-J=C3=B8rgensen?= , Jiri Benc , Jesper Dangaard Brouer , Eelco Chaudron , ast@kernel.org, Daniel Borkmann , Lorenzo Bianconi , David Ahern , Andrii Nakryiko , Alexei Starovoitov , John Fastabend , Maciej Fijalkowski , =?utf-8?b?QmrDtnJuIFQ=?= =?utf-8?b?w7ZwZWw=?= , Hangbin Liu Subject: [PATCHv3 bpf-next 1/4] bpf: run devmap xdp_prog on flush instead of bulk enqueue Date: Thu, 25 Mar 2021 17:27:30 +0800 Message-Id: <20210325092733.3058653-2-liuhangbin@gmail.com> X-Mailer: git-send-email 2.26.2 In-Reply-To: <20210325092733.3058653-1-liuhangbin@gmail.com> References: <20210325092733.3058653-1-liuhangbin@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Jesper Dangaard Brouer This changes the devmap XDP program support to run the program when the bulk queue is flushed instead of before the frame is enqueued. This has a couple of benefits: - It "sorts" the packets by destination devmap entry, and then runs the same BPF program on all the packets in sequence. This ensures that we keep the XDP program and destination device properties hot in I-cache. - It makes the multicast implementation simpler because it can just enqueue packets using bq_enqueue() without having to deal with the devmap program at all. The drawback is that if the devmap program drops the packet, the enqueue step is redundant. However, arguably this is mostly visible in a micro-benchmark, and with more mixed traffic the I-cache benefit should win out. The performance impact of just this patch is as follows: When bq_xmit_all() is called from bq_enqueue(), another packet will always be enqueued immediately after, so clearing dev_rx, xdp_prog and flush_node in bq_xmit_all() is redundant. Move the clear to __dev_flush(), and only check them once in bq_enqueue() since they are all modified together. By using xdp_redirect_map in sample/bpf and send pkts via pktgen cmd: ./pktgen_sample03_burst_single_flow.sh -i eno1 -d $dst_ip -m $dst_mac -t 10 -s 64 And do XDP_DROP on veth peer. There are about +/- 0.1M deviation for native testing, the performance improved for the base-case, but some drop back with xdp devmap prog attached. Version | Test | Generic | Native | Native + 2nd xdp_prog 5.12 rc2 | xdp_redirect_map i40e->i40e | 2.0M | 9.8M | 8.4M 5.12 rc2 | xdp_redirect_map i40e->veth | 1.8M | 12.0M | 10.0M 5.12 rc2 + patch | xdp_redirect_map i40e->i40e | 2.0M | 10.0M | 8.0M 5.12 rc2 + patch | xdp_redirect_map i40e->veth | 1.8M | 12.4M | 9.5M Signed-off-by: Jesper Dangaard Brouer Signed-off-by: Hangbin Liu --- v3: rebase the code based on Lorenzo's "Move drop error path to devmap for XDP_REDIRECT" v2: no update --- kernel/bpf/devmap.c | 127 ++++++++++++++++++++++++++------------------ 1 file changed, 76 insertions(+), 51 deletions(-) diff --git a/kernel/bpf/devmap.c b/kernel/bpf/devmap.c index aa516472ce46..2add12a289c3 100644 --- a/kernel/bpf/devmap.c +++ b/kernel/bpf/devmap.c @@ -57,6 +57,7 @@ struct xdp_dev_bulk_queue { struct list_head flush_node; struct net_device *dev; struct net_device *dev_rx; + struct bpf_prog *xdp_prog; unsigned int count; }; @@ -326,22 +327,71 @@ bool dev_map_can_have_prog(struct bpf_map *map) return false; } +static int dev_map_bpf_prog_run(struct bpf_prog *xdp_prog, + struct xdp_frame **frames, int n, + struct net_device *dev) +{ + struct xdp_txq_info txq = { .dev = dev }; + struct xdp_buff xdp; + int i, nframes = 0; + + for (i = 0; i < n; i++) { + struct xdp_frame *xdpf = frames[i]; + u32 act; + int err; + + xdp_convert_frame_to_buff(xdpf, &xdp); + xdp.txq = &txq; + + act = bpf_prog_run_xdp(xdp_prog, &xdp); + switch (act) { + case XDP_PASS: + err = xdp_update_frame_from_buff(&xdp, xdpf); + if (unlikely(err < 0)) + xdp_return_frame_rx_napi(xdpf); + else + frames[nframes++] = xdpf; + break; + default: + bpf_warn_invalid_xdp_action(act); + fallthrough; + case XDP_ABORTED: + trace_xdp_exception(dev, xdp_prog, act); + fallthrough; + case XDP_DROP: + xdp_return_frame_rx_napi(xdpf); + break; + } + } + return nframes; /* sent frames count */ +} + static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) { struct net_device *dev = bq->dev; - int sent = 0, err = 0; + int sent = 0, drops = 0, err = 0; + unsigned int cnt = bq->count; + int to_send = cnt; int i; - if (unlikely(!bq->count)) + if (unlikely(!cnt)) return; - for (i = 0; i < bq->count; i++) { + for (i = 0; i < cnt; i++) { struct xdp_frame *xdpf = bq->q[i]; prefetch(xdpf); } - sent = dev->netdev_ops->ndo_xdp_xmit(dev, bq->count, bq->q, flags); + if (bq->xdp_prog) { + to_send = dev_map_bpf_prog_run(bq->xdp_prog, bq->q, cnt, dev); + if (!to_send) + goto out; + + drops = cnt - to_send; + } + + sent = dev->netdev_ops->ndo_xdp_xmit(dev, to_send, bq->q, flags); if (sent < 0) { /* If ndo_xdp_xmit fails with an errno, no frames have * been xmit'ed. @@ -353,13 +403,13 @@ static void bq_xmit_all(struct xdp_dev_bulk_queue *bq, u32 flags) /* If not all frames have been transmitted, it is our * responsibility to free them */ - for (i = sent; unlikely(i < bq->count); i++) + for (i = sent; unlikely(i < to_send); i++) xdp_return_frame_rx_napi(bq->q[i]); - trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, bq->count - sent, err); - bq->dev_rx = NULL; +out: + drops = cnt - sent; bq->count = 0; - __list_del_clearprev(&bq->flush_node); + trace_xdp_devmap_xmit(bq->dev_rx, dev, sent, drops, err); } /* __dev_flush is called from xdp_do_flush() which _must_ be signaled @@ -377,8 +427,12 @@ void __dev_flush(void) struct list_head *flush_list = this_cpu_ptr(&dev_flush_list); struct xdp_dev_bulk_queue *bq, *tmp; - list_for_each_entry_safe(bq, tmp, flush_list, flush_node) + list_for_each_entry_safe(bq, tmp, flush_list, flush_node) { bq_xmit_all(bq, XDP_XMIT_FLUSH); + bq->dev_rx = NULL; + bq->xdp_prog = NULL; + __list_del_clearprev(&bq->flush_node); + } } /* rcu_read_lock (from syscall and BPF contexts) ensures that if a delete and/or @@ -401,7 +455,7 @@ static void *__dev_map_lookup_elem(struct bpf_map *map, u32 key) * Thus, safe percpu variable access. */ static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf, - struct net_device *dev_rx) + struct net_device *dev_rx, struct bpf_prog *xdp_prog) { struct list_head *flush_list = this_cpu_ptr(&dev_flush_list); struct xdp_dev_bulk_queue *bq = this_cpu_ptr(dev->xdp_bulkq); @@ -412,18 +466,22 @@ static void bq_enqueue(struct net_device *dev, struct xdp_frame *xdpf, /* Ingress dev_rx will be the same for all xdp_frame's in * bulk_queue, because bq stored per-CPU and must be flushed * from net_device drivers NAPI func end. + * + * Do the same with xdp_prog and flush_list since these fields + * are only ever modified together. */ - if (!bq->dev_rx) + if (!bq->dev_rx) { bq->dev_rx = dev_rx; + bq->xdp_prog = xdp_prog; + list_add(&bq->flush_node, flush_list); + } bq->q[bq->count++] = xdpf; - - if (!bq->flush_node.prev) - list_add(&bq->flush_node, flush_list); } static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, - struct net_device *dev_rx) + struct net_device *dev_rx, + struct bpf_prog *xdp_prog) { struct xdp_frame *xdpf; int err; @@ -439,42 +497,14 @@ static inline int __xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, if (unlikely(!xdpf)) return -EOVERFLOW; - bq_enqueue(dev, xdpf, dev_rx); + bq_enqueue(dev, xdpf, dev_rx, xdp_prog); return 0; } -static struct xdp_buff *dev_map_run_prog(struct net_device *dev, - struct xdp_buff *xdp, - struct bpf_prog *xdp_prog) -{ - struct xdp_txq_info txq = { .dev = dev }; - u32 act; - - xdp_set_data_meta_invalid(xdp); - xdp->txq = &txq; - - act = bpf_prog_run_xdp(xdp_prog, xdp); - switch (act) { - case XDP_PASS: - return xdp; - case XDP_DROP: - break; - default: - bpf_warn_invalid_xdp_action(act); - fallthrough; - case XDP_ABORTED: - trace_xdp_exception(dev, xdp_prog, act); - break; - } - - xdp_return_buff(xdp); - return NULL; -} - int dev_xdp_enqueue(struct net_device *dev, struct xdp_buff *xdp, struct net_device *dev_rx) { - return __xdp_enqueue(dev, xdp, dev_rx); + return __xdp_enqueue(dev, xdp, dev_rx, NULL); } int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, @@ -482,12 +512,7 @@ int dev_map_enqueue(struct bpf_dtab_netdev *dst, struct xdp_buff *xdp, { struct net_device *dev = dst->dev; - if (dst->xdp_prog) { - xdp = dev_map_run_prog(dev, xdp, dst->xdp_prog); - if (!xdp) - return 0; - } - return __xdp_enqueue(dev, xdp, dev_rx); + return __xdp_enqueue(dev, xdp, dev_rx, dst->xdp_prog); } int dev_map_generic_redirect(struct bpf_dtab_netdev *dst, struct sk_buff *skb,