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=-8.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=unavailable 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 3BEB4C433DF for ; Thu, 25 Jun 2020 21:29:13 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 2405F2076E for ; Thu, 25 Jun 2020 21:29:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391160AbgFYV3M (ORCPT ); Thu, 25 Jun 2020 17:29:12 -0400 Received: from www62.your-server.de ([213.133.104.62]:33648 "EHLO www62.your-server.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2390722AbgFYV3M (ORCPT ); Thu, 25 Jun 2020 17:29:12 -0400 Received: from sslproxy06.your-server.de ([78.46.172.3]) by www62.your-server.de with esmtpsa (TLSv1.2:DHE-RSA-AES256-GCM-SHA384:256) (Exim 4.89_1) (envelope-from ) id 1joZQa-0002nD-Ee; Thu, 25 Jun 2020 23:29:00 +0200 Received: from [178.196.57.75] (helo=pc-9.home) by sslproxy06.your-server.de with esmtpsa (TLSv1.3:TLS_AES_256_GCM_SHA384:256) (Exim 4.92) (envelope-from ) id 1joZQa-000BQB-2e; Thu, 25 Jun 2020 23:29:00 +0200 Subject: Re: [PATCH v4 bpf-next 6/9] bpf: cpumap: implement XDP_REDIRECT for eBPF programs attached to map entries To: Lorenzo Bianconi , netdev@vger.kernel.org, bpf@vger.kernel.org Cc: davem@davemloft.net, ast@kernel.org, brouer@redhat.com, toke@redhat.com, lorenzo.bianconi@redhat.com, dsahern@kernel.org, andrii.nakryiko@gmail.com References: From: Daniel Borkmann Message-ID: <01248413-7675-d35e-323e-7d2e69128b45@iogearbox.net> Date: Thu, 25 Jun 2020 23:28:59 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:60.0) Gecko/20100101 Thunderbird/60.7.2 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Authenticated-Sender: daniel@iogearbox.net X-Virus-Scanned: Clear (ClamAV 0.102.3/25854/Thu Jun 25 15:16:08 2020) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 6/24/20 5:33 PM, Lorenzo Bianconi wrote: > Introduce XDP_REDIRECT support for eBPF programs attached to cpumap > entries. > This patch has been tested on Marvell ESPRESSObin using a modified > version of xdp_redirect_cpu sample in order to attach a XDP program > to CPUMAP entries to perform a redirect on the mvneta interface. > In particular the following scenario has been tested: > > rq (cpu0) --> mvneta - XDP_REDIRECT (cpu0) --> CPUMAP - XDP_REDIRECT (cpu1) --> mvneta > > $./xdp_redirect_cpu -p xdp_cpu_map0 -d eth0 -c 1 -e xdp_redirect \ > -f xdp_redirect_kern.o -m tx_port -r eth0 > > tx: 285.2 Kpps rx: 285.2 Kpps > > Attaching a simple XDP program on eth0 to perform XDP_TX gives > comparable results: > > tx: 288.4 Kpps rx: 288.4 Kpps > > Acked-by: Jesper Dangaard Brouer > Co-developed-by: Jesper Dangaard Brouer > Signed-off-by: Jesper Dangaard Brouer > Signed-off-by: Lorenzo Bianconi > --- > include/net/xdp.h | 1 + > include/trace/events/xdp.h | 6 ++++-- > kernel/bpf/cpumap.c | 17 +++++++++++++++-- > 3 files changed, 20 insertions(+), 4 deletions(-) > > diff --git a/include/net/xdp.h b/include/net/xdp.h > index 83b9e0142b52..5be0d4d65b94 100644 > --- a/include/net/xdp.h > +++ b/include/net/xdp.h > @@ -99,6 +99,7 @@ struct xdp_frame { > }; > > struct xdp_cpumap_stats { > + unsigned int redirect; > unsigned int pass; > unsigned int drop; > }; > diff --git a/include/trace/events/xdp.h b/include/trace/events/xdp.h > index e2c99f5bee39..cd24e8a59529 100644 > --- a/include/trace/events/xdp.h > +++ b/include/trace/events/xdp.h > @@ -190,6 +190,7 @@ TRACE_EVENT(xdp_cpumap_kthread, > __field(int, sched) > __field(unsigned int, xdp_pass) > __field(unsigned int, xdp_drop) > + __field(unsigned int, xdp_redirect) > ), > > TP_fast_assign( > @@ -201,18 +202,19 @@ TRACE_EVENT(xdp_cpumap_kthread, > __entry->sched = sched; > __entry->xdp_pass = xdp_stats->pass; > __entry->xdp_drop = xdp_stats->drop; > + __entry->xdp_redirect = xdp_stats->redirect; > ), > > TP_printk("kthread" > " cpu=%d map_id=%d action=%s" > " processed=%u drops=%u" > " sched=%d" > - " xdp_pass=%u xdp_drop=%u", > + " xdp_pass=%u xdp_drop=%u xdp_redirect=%u", > __entry->cpu, __entry->map_id, > __print_symbolic(__entry->act, __XDP_ACT_SYM_TAB), > __entry->processed, __entry->drops, > __entry->sched, > - __entry->xdp_pass, __entry->xdp_drop) > + __entry->xdp_pass, __entry->xdp_drop, __entry->xdp_redirect) > ); > > TRACE_EVENT(xdp_cpumap_enqueue, > diff --git a/kernel/bpf/cpumap.c b/kernel/bpf/cpumap.c > index 4e4cd240f07b..c0b2f265ccb2 100644 > --- a/kernel/bpf/cpumap.c > +++ b/kernel/bpf/cpumap.c > @@ -240,7 +240,7 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, > xdp_set_return_frame_no_direct(); > xdp.rxq = &rxq; > > - rcu_read_lock(); > + rcu_read_lock_bh(); > > prog = READ_ONCE(rcpu->prog); > for (i = 0; i < n; i++) { > @@ -266,6 +266,16 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, > stats->pass++; > } > break; > + case XDP_REDIRECT: > + err = xdp_do_redirect(xdpf->dev_rx, &xdp, > + prog); > + if (unlikely(err)) { > + xdp_return_frame(xdpf); > + stats->drop++; > + } else { > + stats->redirect++; > + } Could we do better with all the accounting and do this from /inside/ BPF tracing prog instead (otherwise too bad we need to have it here even if the tracepoint is disabled)? > + break; > default: > bpf_warn_invalid_xdp_action(act); > /* fallthrough */ > @@ -276,7 +286,10 @@ static int cpu_map_bpf_prog_run_xdp(struct bpf_cpu_map_entry *rcpu, > } > } > > - rcu_read_unlock(); > + if (stats->redirect) > + xdp_do_flush_map(); > + > + rcu_read_unlock_bh(); /* resched point, may call do_softirq() */ > xdp_clear_return_frame_no_direct(); Hm, this looks incorrect. Why do you call the xdp_clear_return_frame_no_direct() /after/ the possibility where there is a rescheduling point for softirq? > return nframes; >