From mboxrd@z Thu Jan 1 00:00:00 1970 From: Soheil Hassas Yeganeh Subject: [PATCH net-next 2/2] tcp: adjust rcv zerocopy hints based on frag sizes Date: Wed, 26 Sep 2018 16:57:04 -0400 Message-ID: <20180926205704.42754-2-soheil.kdev@gmail.com> References: <20180926205704.42754-1-soheil.kdev@gmail.com> Mime-Version: 1.0 Content-Transfer-Encoding: 8bit Cc: edumazet@google.com, Soheil Hassas Yeganeh To: davem@davemloft.net, netdev@vger.kernel.org Return-path: Received: from mail-qt1-f196.google.com ([209.85.160.196]:37442 "EHLO mail-qt1-f196.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726877AbeI0DL4 (ORCPT ); Wed, 26 Sep 2018 23:11:56 -0400 Received: by mail-qt1-f196.google.com with SMTP id n6-v6so470938qtl.4 for ; Wed, 26 Sep 2018 13:57:08 -0700 (PDT) In-Reply-To: <20180926205704.42754-1-soheil.kdev@gmail.com> Sender: netdev-owner@vger.kernel.org List-ID: From: Soheil Hassas Yeganeh When SKBs are coalesced, we can have SKBs with different frag sizes. Some with PAGE_SIZE and some not with PAGE_SIZE. Since recv_skip_hint is always set to the full SKB size, it can overestimate the amount that should be read using normal read for coalesced packets. Change the recv_skip_hint so that it only includes the first frags that are not of PAGE_SIZE. Signed-off-by: Soheil Hassas Yeganeh Signed-off-by: Eric Dumazet --- net/ipv4/tcp.c | 11 ++++++++++- 1 file changed, 10 insertions(+), 1 deletion(-) diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 3e17501fc1a1..cdbd423bdeb4 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -1805,8 +1805,17 @@ static int tcp_zerocopy_receive(struct sock *sk, frags++; } } - if (frags->size != PAGE_SIZE || frags->page_offset) + if (frags->size != PAGE_SIZE || frags->page_offset) { + int remaining = zc->recv_skip_hint; + + while (remaining && (frags->size != PAGE_SIZE || + frags->page_offset)) { + remaining -= frags->size; + frags++; + } + zc->recv_skip_hint -= remaining; break; + } ret = vm_insert_page(vma, address + length, skb_frag_page(frags)); if (ret) -- 2.19.0.605.g01d371f741-goog