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 mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id BADC7C4332F for ; Tue, 16 Nov 2021 00:27:48 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id A7E2C619F6 for ; Tue, 16 Nov 2021 00:27:48 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1349393AbhKPAaj (ORCPT ); Mon, 15 Nov 2021 19:30:39 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:38282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1346139AbhKOT36 (ORCPT ); Mon, 15 Nov 2021 14:29:58 -0500 Received: from mail-pj1-x1033.google.com (mail-pj1-x1033.google.com [IPv6:2607:f8b0:4864:20::1033]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id BF678C04C353 for ; Mon, 15 Nov 2021 11:16:19 -0800 (PST) Received: by mail-pj1-x1033.google.com with SMTP id o6-20020a17090a0a0600b001a64b9a11aeso674014pjo.3 for ; Mon, 15 Nov 2021 11:16:19 -0800 (PST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20210112; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=tYHdmtIMWSVV5HHi5v+leUs3g5lQajgFM9xLbqiXLgU=; b=MnVF/OI4x7XT9JrjN93Zdszyf9LVVIieP/KgyGUIpgRbgGrvTqRQuS5xadKF7y8Gpo caR7YNX+TElILmcJ92+4BMocHmsNqW/VpRtPr60ljsIGpNzUmKfrzuPFkp89/gLLqoOq Q0Od8wHiAq6ZpYjxs+YHEU85Jv9p7mULWnllvAREG/3bfE+4TD6zKwLkDz170W6N7FfY mWoQnnpmE7fE7z0BqbL5NxY4f9VEtbq57RQqksHSIm0yFbRxwDpNxhhRz1N4a0n+N1GY vQ0AHekrDGnTKW8ygxMcMf0KP5lCqZ8Sjz6a0bnipIfZYwwYrvkj3Eok9Air+8/+LPVG I58Q== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=tYHdmtIMWSVV5HHi5v+leUs3g5lQajgFM9xLbqiXLgU=; b=z220HgxzgR/fighPptfe3noUntzrucUIwsPYxhPtwb+1vvqXvljpmQRvkmM2sm/508 DqoIkn46voL9vgeO+f/z8NdhEWo2MSduiqiMfcLiMUc17oJQYqgn3WuSYuhCxtN+g4km S8oSvqR+3ASP2/uXXF7MrjG78VdZkJoEOPdOldIP1VGCiMBp3sYQsNq82bI68d0185R6 Oki0OnvzxITctR5zKHXAPmiI0pWz6Iku5fkYwFTq1GZhlUn6mlpOiFXCaBW5y/YKvpmo h/Cwt08KCHzvA8+QCuHE0hHRe9zUrIwPUKFjnhGyRWPI35S045NFbe9G2ap1+xA3QcYI ppCw== X-Gm-Message-State: AOAM531c53JEQRCpgdH71ZriwLaegqbG9WLaDg6WTHzQjjS0VLss4pit TRD/XJABxGaJAFe1lkoq8rWOpg01e7ni9ykKR4lGBA== X-Google-Smtp-Source: ABdhPJw+lVd2zHcBPZ+FvbAPI1JGJ+NN1dErXXm3fs2m8Ezt/KPXt5EQqHW7pZdkIcTtAGYGoHDQVqcQoSbvkbs9Pm8= X-Received: by 2002:a17:90b:38c7:: with SMTP id nn7mr1095726pjb.105.1637003778996; Mon, 15 Nov 2021 11:16:18 -0800 (PST) MIME-Version: 1.0 References: <20211115190249.3936899-1-eric.dumazet@gmail.com> <20211115190249.3936899-17-eric.dumazet@gmail.com> In-Reply-To: <20211115190249.3936899-17-eric.dumazet@gmail.com> From: Arjun Roy Date: Mon, 15 Nov 2021 11:16:08 -0800 Message-ID: Subject: Re: [PATCH net-next 16/20] tcp: avoid indirect calls to sock_rfree To: Eric Dumazet Cc: "David S . Miller" , Jakub Kicinski , netdev , Eric Dumazet , Soheil Hassas Yeganeh , Neal Cardwell Content-Type: text/plain; charset="UTF-8" Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Mon, Nov 15, 2021 at 11:03 AM Eric Dumazet wrote: > > From: Eric Dumazet > > TCP uses sk_eat_skb() when skbs can be removed from receive queue. > However, the call so skb_orphan() from __kfree_skb() incurs > an indirect call so sock_rfee(), which is more expensive than Possible typo : s/so/to/g ? -Arjun > a direct call, especially for CONFIG_RETPOLINE=y. > > Add tcp_eat_recv_skb() function to make the call before > __kfree_skb(). > > Signed-off-by: Eric Dumazet > --- > net/ipv4/tcp.c | 20 +++++++++++++++----- > 1 file changed, 15 insertions(+), 5 deletions(-) > > diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c > index 9175e0d729f5e65b5fa39acadc5bf9de715854ad..4e7011672aa9a04370b7a03b972fe19cd48ea232 100644 > --- a/net/ipv4/tcp.c > +++ b/net/ipv4/tcp.c > @@ -1580,6 +1580,16 @@ void tcp_cleanup_rbuf(struct sock *sk, int copied) > tcp_send_ack(sk); > } > > +static void tcp_eat_recv_skb(struct sock *sk, struct sk_buff *skb) > +{ > + if (likely(skb->destructor == sock_rfree)) { > + sock_rfree(skb); > + skb->destructor = NULL; > + skb->sk = NULL; > + } > + sk_eat_skb(sk, skb); > +} > + > static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) > { > struct sk_buff *skb; > @@ -1599,7 +1609,7 @@ static struct sk_buff *tcp_recv_skb(struct sock *sk, u32 seq, u32 *off) > * splitted a fat GRO packet, while we released socket lock > * in skb_splice_bits() > */ > - sk_eat_skb(sk, skb); > + tcp_eat_recv_skb(sk, skb); > } > return NULL; > } > @@ -1665,11 +1675,11 @@ int tcp_read_sock(struct sock *sk, read_descriptor_t *desc, > continue; > } > if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) { > - sk_eat_skb(sk, skb); > + tcp_eat_recv_skb(sk, skb); > ++seq; > break; > } > - sk_eat_skb(sk, skb); > + tcp_eat_recv_skb(sk, skb); > if (!desc->count) > break; > WRITE_ONCE(tp->copied_seq, seq); > @@ -2481,14 +2491,14 @@ static int tcp_recvmsg_locked(struct sock *sk, struct msghdr *msg, size_t len, > if (TCP_SKB_CB(skb)->tcp_flags & TCPHDR_FIN) > goto found_fin_ok; > if (!(flags & MSG_PEEK)) > - sk_eat_skb(sk, skb); > + tcp_eat_recv_skb(sk, skb); > continue; > > found_fin_ok: > /* Process the FIN. */ > WRITE_ONCE(*seq, *seq + 1); > if (!(flags & MSG_PEEK)) > - sk_eat_skb(sk, skb); > + tcp_eat_recv_skb(sk, skb); > break; > } while (len > 0); > > -- > 2.34.0.rc1.387.gb447b232ab-goog >