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=-10.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 EFCBFC43461 for ; Thu, 22 Apr 2021 16:54:01 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id D4C0A60232 for ; Thu, 22 Apr 2021 16:54:01 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S238083AbhDVQyf (ORCPT ); Thu, 22 Apr 2021 12:54:35 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:33186 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S236459AbhDVQyd (ORCPT ); Thu, 22 Apr 2021 12:54:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1619110438; 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=L67e35Y8xefipQs4qC6+RLpK6ouDIFBfNvy+uHX4DBo=; b=AHxGH+OZ18vjsdeG3HFyBJBA6IAl+ce3DpCS7TVbH7oUf4Mv66JQAoXm6XzUxZ14GCYFcw uvClTySAlha49xlgndV9uVtl9ze8QzjQME4kDVyX3dHUjfYYgP5+PC9jzzjjDgWD+lGgUC c4y8XPuUkecjnVY1mKMbbAXMPvqA8Gc= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-488-sCyT0bQ0MnKfk83RlvTJmw-1; Thu, 22 Apr 2021 12:53:54 -0400 X-MC-Unique: sCyT0bQ0MnKfk83RlvTJmw-1 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 6D1E5A40C7; Thu, 22 Apr 2021 16:53:52 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id F175B5C261; Thu, 22 Apr 2021 16:53:34 +0000 (UTC) Date: Thu, 22 Apr 2021 18:53:32 +0200 From: Jesper Dangaard Brouer To: Hangbin Liu Cc: bpf@vger.kernel.org, netdev@vger.kernel.org, Toke =?UTF-8?B?SMO4aWxh?= =?UTF-8?B?bmQtSsO4cmdlbnNlbg==?= , Jiri Benc , 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=?= , Martin KaFai Lau , brouer@redhat.com Subject: Re: [PATCHv9 bpf-next 2/4] xdp: extend xdp_redirect_map with broadcast support Message-ID: <20210422185332.3199ca2e@carbon> In-Reply-To: <20210422071454.2023282-3-liuhangbin@gmail.com> References: <20210422071454.2023282-1-liuhangbin@gmail.com> <20210422071454.2023282-3-liuhangbin@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Thu, 22 Apr 2021 15:14:52 +0800 Hangbin Liu wrote: > diff --git a/net/core/filter.c b/net/core/filter.c > index cae56d08a670..afec192c3b21 100644 > --- a/net/core/filter.c > +++ b/net/core/filter.c [...] > int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, > struct bpf_prog *xdp_prog) > { > @@ -3933,6 +3950,7 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, > enum bpf_map_type map_type = ri->map_type; > void *fwd = ri->tgt_value; > u32 map_id = ri->map_id; > + struct bpf_map *map; > int err; > > ri->map_id = 0; /* Valid map id idr range: [1,INT_MAX[ */ > @@ -3942,7 +3960,12 @@ int xdp_do_redirect(struct net_device *dev, struct xdp_buff *xdp, > case BPF_MAP_TYPE_DEVMAP: > fallthrough; > case BPF_MAP_TYPE_DEVMAP_HASH: > - err = dev_map_enqueue(fwd, xdp, dev); > + map = xchg(&ri->map, NULL); Hmm, this looks dangerous for performance to have on this fast-path. The xchg call can be expensive, AFAIK this is an atomic operation. > + if (map) > + err = dev_map_enqueue_multi(xdp, dev, map, > + ri->flags & BPF_F_EXCLUDE_INGRESS); > + else > + err = dev_map_enqueue(fwd, xdp, dev); > break; > case BPF_MAP_TYPE_CPUMAP: > err = cpu_map_enqueue(fwd, xdp, dev); > @@ -3984,13 +4007,19 @@ static int xdp_do_generic_redirect_map(struct net_device *dev, > enum bpf_map_type map_type, u32 map_id) > { > struct bpf_redirect_info *ri = this_cpu_ptr(&bpf_redirect_info); > + struct bpf_map *map; > int err; > > switch (map_type) { > case BPF_MAP_TYPE_DEVMAP: > fallthrough; > case BPF_MAP_TYPE_DEVMAP_HASH: > - err = dev_map_generic_redirect(fwd, skb, xdp_prog); > + map = xchg(&ri->map, NULL); Same here! > + if (map) > + err = dev_map_redirect_multi(dev, skb, xdp_prog, map, > + ri->flags & BPF_F_EXCLUDE_INGRESS); > + else > + err = dev_map_generic_redirect(fwd, skb, xdp_prog); > if (unlikely(err)) > goto err; > break; -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer