From patchwork Wed Nov 25 06:48:57 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Xuan Zhuo X-Patchwork-Id: 11930435 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,UNPARSEABLE_RELAY,USER_AGENT_GIT 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 1D4EAC64E7A for ; Wed, 25 Nov 2020 06:49:25 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id F305920DD4 for ; Wed, 25 Nov 2020 06:49:24 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727109AbgKYGtF (ORCPT ); Wed, 25 Nov 2020 01:49:05 -0500 Received: from out30-130.freemail.mail.aliyun.com ([115.124.30.130]:43290 "EHLO out30-130.freemail.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727031AbgKYGtF (ORCPT ); Wed, 25 Nov 2020 01:49:05 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R261e4;CH=green;DM=||false|;DS=||;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e01e04395;MF=xuanzhuo@linux.alibaba.com;NM=1;PH=DS;RN=18;SR=0;TI=SMTPD_---0UGTnDg-_1606286939; Received: from localhost(mailfrom:xuanzhuo@linux.alibaba.com fp:SMTPD_---0UGTnDg-_1606286939) by smtp.aliyun-inc.com(127.0.0.1); Wed, 25 Nov 2020 14:49:00 +0800 From: Xuan Zhuo To: magnus.karlsson@gmail.com Cc: =?utf-8?b?QmrDtnJuIFTDtnBlbA==?= , Magnus Karlsson , Jonathan Lemon , "David S. Miller" , Jakub Kicinski , Alexei Starovoitov , Daniel Borkmann , Jesper Dangaard Brouer , John Fastabend , Martin KaFai Lau , Song Liu , Yonghong Song , Andrii Nakryiko , KP Singh , netdev@vger.kernel.org (open list:XDP SOCKETS (AF_XDP)), bpf@vger.kernel.org (open list:XDP SOCKETS (AF_XDP)), linux-kernel@vger.kernel.org (open list) Subject: [PATCH bpf v2 2/2] xsk: change the tx writeable condition Date: Wed, 25 Nov 2020 14:48:57 +0800 Message-Id: <4fd58d473f4548dc6e9e24ea9876c802d5d584b4.1606285978.git.xuanzhuo@linux.alibaba.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: References: In-Reply-To: References: Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net Modify the tx writeable condition from the queue is not full to the number of present tx queues is less than the half of the total number of queues. Because the tx queue not full is a very short time, this will cause a large number of EPOLLOUT events, and cause a large number of process wake up. Signed-off-by: Xuan Zhuo Acked-by: Magnus Karlsson --- net/xdp/xsk.c | 16 +++++++++++++--- net/xdp/xsk_queue.h | 6 ++++++ 2 files changed, 19 insertions(+), 3 deletions(-) diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c index 0df8651..22e35e9 100644 --- a/net/xdp/xsk.c +++ b/net/xdp/xsk.c @@ -211,6 +211,14 @@ static int __xsk_rcv(struct xdp_sock *xs, struct xdp_buff *xdp, u32 len, return 0; } +static bool xsk_tx_writeable(struct xdp_sock *xs) +{ + if (xskq_cons_present_entries(xs->tx) > xs->tx->nentries / 2) + return false; + + return true; +} + static bool xsk_is_bound(struct xdp_sock *xs) { if (READ_ONCE(xs->state) == XSK_BOUND) { @@ -296,7 +304,8 @@ void xsk_tx_release(struct xsk_buff_pool *pool) rcu_read_lock(); list_for_each_entry_rcu(xs, &pool->xsk_tx_list, tx_list) { __xskq_cons_release(xs->tx); - xs->sk.sk_write_space(&xs->sk); + if (xsk_tx_writeable(xs)) + xs->sk.sk_write_space(&xs->sk); } rcu_read_unlock(); } @@ -499,7 +508,8 @@ static int xsk_generic_xmit(struct sock *sk) out: if (sent_frame) - sk->sk_write_space(sk); + if (xsk_tx_writeable(xs)) + sk->sk_write_space(sk); mutex_unlock(&xs->mutex); return err; @@ -556,7 +566,7 @@ static __poll_t xsk_poll(struct file *file, struct socket *sock, if (xs->rx && !xskq_prod_is_empty(xs->rx)) mask |= EPOLLIN | EPOLLRDNORM; - if (xs->tx && !xskq_cons_is_full(xs->tx)) + if (xs->tx && xsk_tx_writeable(xs)) mask |= EPOLLOUT | EPOLLWRNORM; return mask; diff --git a/net/xdp/xsk_queue.h b/net/xdp/xsk_queue.h index b936c46..b655004 100644 --- a/net/xdp/xsk_queue.h +++ b/net/xdp/xsk_queue.h @@ -307,6 +307,12 @@ static inline bool xskq_cons_is_full(struct xsk_queue *q) q->nentries; } +static inline __u64 xskq_cons_present_entries(struct xsk_queue *q) +{ + /* No barriers needed since data is not accessed */ + return READ_ONCE(q->ring->producer) - READ_ONCE(q->ring->consumer); +} + /* Functions for producers */ static inline u32 xskq_prod_nb_free(struct xsk_queue *q, u32 max)