From mboxrd@z Thu Jan 1 00:00:00 1970 From: John Fastabend Subject: [bpf-next PATCH 4/7] net: do_tcp_sendpages flag to avoid SKBTX_SHARED_FRAG Date: Fri, 12 Jan 2018 10:10:55 -0800 Message-ID: <20180112181055.21531.95322.stgit@john-Precision-Tower-5810> References: <20180112175029.21531.54693.stgit@john-Precision-Tower-5810> Mime-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Cc: netdev@vger.kernel.org, kafai@fb.com To: borkmann@iogearbox.net, john.fastabend@gmail.com, ast@kernel.org Return-path: Received: from mail-pg0-f67.google.com ([74.125.83.67]:36251 "EHLO mail-pg0-f67.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S964996AbeALSLG (ORCPT ); Fri, 12 Jan 2018 13:11:06 -0500 Received: by mail-pg0-f67.google.com with SMTP id j2so5064146pgv.3 for ; Fri, 12 Jan 2018 10:11:06 -0800 (PST) In-Reply-To: <20180112175029.21531.54693.stgit@john-Precision-Tower-5810> Sender: netdev-owner@vger.kernel.org List-ID: When calling do_tcp_sendpages() from in kernel and we know the data has no references from user side we can omit SKBTX_SHARED_FRAG flag. This patch adds an internal flag, NO_SKBTX_SHARED_FRAG that can be used to omit setting SKBTX_SHARED_FRAG. Signed-off-by: John Fastabend --- include/linux/socket.h | 1 + net/ipv4/tcp.c | 4 +++- 2 files changed, 4 insertions(+), 1 deletion(-) diff --git a/include/linux/socket.h b/include/linux/socket.h index 9286a5a..add9360 100644 --- a/include/linux/socket.h +++ b/include/linux/socket.h @@ -287,6 +287,7 @@ struct ucred { #define MSG_SENDPAGE_NOTLAST 0x20000 /* sendpage() internal : not the last page */ #define MSG_BATCH 0x40000 /* sendmmsg(): more messages coming */ #define MSG_EOF MSG_FIN +#define MSG_NO_SHARED_FRAGS 0x80000 /* sendpage() internal : page frags are not shared */ #define MSG_ZEROCOPY 0x4000000 /* Use user data in kernel path */ #define MSG_FASTOPEN 0x20000000 /* Send data in TCP SYN */ diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c index 7ac583a..56c6f49 100644 --- a/net/ipv4/tcp.c +++ b/net/ipv4/tcp.c @@ -995,7 +995,9 @@ ssize_t do_tcp_sendpages(struct sock *sk, struct page *page, int offset, get_page(page); skb_fill_page_desc(skb, i, page, offset, copy); } - skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; + + if (!(flags & MSG_NO_SHARED_FRAGS)) + skb_shinfo(skb)->tx_flags |= SKBTX_SHARED_FRAG; skb->len += copy; skb->data_len += copy;