From: David Howells <dhowells@redhat.com>
To: Matthew Wilcox <willy@infradead.org>,
"David S. Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>
Cc: David Howells <dhowells@redhat.com>,
Al Viro <viro@zeniv.linux.org.uk>,
Christoph Hellwig <hch@infradead.org>,
Jens Axboe <axboe@kernel.dk>, Jeff Layton <jlayton@kernel.org>,
Christian Brauner <brauner@kernel.org>,
Chuck Lever III <chuck.lever@oracle.com>,
Linus Torvalds <torvalds@linux-foundation.org>,
netdev@vger.kernel.org, linux-fsdevel@vger.kernel.org,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Subject: [RFC PATCH v2 08/48] tcp: Support MSG_SPLICE_PAGES
Date: Wed, 29 Mar 2023 15:13:14 +0100 [thread overview]
Message-ID: <20230329141354.516864-9-dhowells@redhat.com> (raw)
In-Reply-To: <20230329141354.516864-1-dhowells@redhat.com>
Make TCP's sendmsg() support MSG_SPLICE_PAGES. This causes pages to be
spliced from the source iterator if possible (the iterator must be
ITER_BVEC and the pages must be spliceable).
This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.
Signed-off-by: David Howells <dhowells@redhat.com>
cc: Eric Dumazet <edumazet@google.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: netdev@vger.kernel.org
---
net/ipv4/tcp.c | 67 ++++++++++++++++++++++++++++++++++++++++++++------
1 file changed, 60 insertions(+), 7 deletions(-)
diff --git a/net/ipv4/tcp.c b/net/ipv4/tcp.c
index 288693981b00..910b327c236e 100644
--- a/net/ipv4/tcp.c
+++ b/net/ipv4/tcp.c
@@ -1220,7 +1220,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
int flags, err, copied = 0;
int mss_now = 0, size_goal, copied_syn = 0;
int process_backlog = 0;
- bool zc = false;
+ int zc = 0;
long timeo;
flags = msg->msg_flags;
@@ -1231,17 +1231,22 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
if (msg->msg_ubuf) {
uarg = msg->msg_ubuf;
net_zcopy_get(uarg);
- zc = sk->sk_route_caps & NETIF_F_SG;
+ if (sk->sk_route_caps & NETIF_F_SG)
+ zc = 1;
} else if (sock_flag(sk, SOCK_ZEROCOPY)) {
uarg = msg_zerocopy_realloc(sk, size, skb_zcopy(skb));
if (!uarg) {
err = -ENOBUFS;
goto out_err;
}
- zc = sk->sk_route_caps & NETIF_F_SG;
- if (!zc)
+ if (sk->sk_route_caps & NETIF_F_SG)
+ zc = 1;
+ else
uarg_to_msgzc(uarg)->zerocopy = 0;
}
+ } else if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES) && size) {
+ if (sk->sk_route_caps & NETIF_F_SG)
+ zc = 2;
}
if (unlikely(flags & MSG_FASTOPEN || inet_sk(sk)->defer_connect) &&
@@ -1304,7 +1309,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
goto do_error;
while (msg_data_left(msg)) {
- int copy = 0;
+ ssize_t copy = 0;
skb = tcp_write_queue_tail(sk);
if (skb)
@@ -1345,7 +1350,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
if (copy > msg_data_left(msg))
copy = msg_data_left(msg);
- if (!zc) {
+ if (zc == 0) {
bool merge = true;
int i = skb_shinfo(skb)->nr_frags;
struct page_frag *pfrag = sk_page_frag(sk);
@@ -1390,7 +1395,7 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
page_ref_inc(pfrag->page);
}
pfrag->offset += copy;
- } else {
+ } else if (zc == 1) {
/* First append to a fragless skb builds initial
* pure zerocopy skb
*/
@@ -1411,6 +1416,54 @@ int tcp_sendmsg_locked(struct sock *sk, struct msghdr *msg, size_t size)
if (err < 0)
goto do_error;
copy = err;
+ } else if (zc == 2) {
+ /* Splice in data. */
+ struct page *page = NULL, **pages = &page;
+ size_t off = 0, part;
+ bool can_coalesce;
+ int i = skb_shinfo(skb)->nr_frags;
+
+ copy = iov_iter_extract_pages(&msg->msg_iter, &pages,
+ copy, 1, 0, &off);
+ if (copy <= 0) {
+ err = copy ?: -EIO;
+ goto do_error;
+ }
+
+ can_coalesce = skb_can_coalesce(skb, i, page, off);
+ if (!can_coalesce && i >= READ_ONCE(sysctl_max_skb_frags)) {
+ tcp_mark_push(tp, skb);
+ iov_iter_revert(&msg->msg_iter, copy);
+ goto new_segment;
+ }
+ if (tcp_downgrade_zcopy_pure(sk, skb)) {
+ iov_iter_revert(&msg->msg_iter, copy);
+ goto wait_for_space;
+ }
+
+ part = tcp_wmem_schedule(sk, copy);
+ iov_iter_revert(&msg->msg_iter, copy - part);
+ if (!part)
+ goto wait_for_space;
+ copy = part;
+
+ if (can_coalesce) {
+ skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
+ } else {
+ get_page(page);
+ skb_fill_page_desc_noacc(skb, i, page, off, copy);
+ }
+ page = NULL;
+
+ if (!(flags & MSG_NO_SHARED_FRAGS))
+ skb_shinfo(skb)->flags |= SKBFL_SHARED_FRAG;
+
+ skb->len += copy;
+ skb->data_len += copy;
+ skb->truesize += copy;
+ sk_wmem_queued_add(sk, copy);
+ sk_mem_charge(sk, copy);
+
}
if (!copied)
next prev parent reply other threads:[~2023-03-29 14:16 UTC|newest]
Thread overview: 79+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-03-29 14:13 [RFC PATCH v2 00/48] splice, net: Replace sendpage with sendmsg(MSG_SPLICE_PAGES) David Howells
2023-03-29 14:13 ` [RFC PATCH v2 01/48] netfs: Fix netfs_extract_iter_to_sg() for ITER_UBUF/IOVEC David Howells
2023-03-29 14:13 ` [RFC PATCH v2 02/48] iov_iter: Remove last_offset member David Howells
2023-03-29 14:13 ` [RFC PATCH v2 03/48] iov_iter: Add an iterator-of-iterators David Howells
2023-03-29 14:13 ` [RFC PATCH v2 04/48] net: Declare MSG_SPLICE_PAGES internal sendmsg() flag David Howells
2023-03-30 14:28 ` Willem de Bruijn
2023-03-30 15:07 ` David Howells
2023-03-30 17:51 ` Willem de Bruijn
2023-03-29 14:13 ` [RFC PATCH v2 05/48] mm: Move the page fragment allocator from page_alloc.c into its own file David Howells
2023-03-29 14:13 ` [RFC PATCH v2 06/48] mm: Make the page_frag_cache allocator use multipage folios David Howells
2023-03-29 14:13 ` [RFC PATCH v2 07/48] mm: Make the page_frag_cache allocator use per-cpu David Howells
2023-03-29 14:13 ` David Howells [this message]
2023-03-29 14:13 ` [RFC PATCH v2 09/48] tcp: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data David Howells
2023-03-29 14:13 ` [RFC PATCH v2 10/48] tcp: Convert do_tcp_sendpages() to use MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 11/48] tcp_bpf: Inline do_tcp_sendpages as it's now a wrapper around tcp_sendmsg David Howells
2023-03-29 14:13 ` [RFC PATCH v2 12/48] espintcp: Inline do_tcp_sendpages() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 13/48] tls: " David Howells
2023-03-29 14:13 ` [RFC PATCH v2 14/48] siw: " David Howells
2023-03-29 14:13 ` [RFC PATCH v2 15/48] tcp: Fold do_tcp_sendpages() into tcp_sendpage_locked() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 16/48] ip, udp: Support MSG_SPLICE_PAGES David Howells
2023-03-30 14:20 ` Willem de Bruijn
2023-03-30 14:39 ` David Howells
2023-03-30 17:46 ` Willem de Bruijn
2023-03-30 15:11 ` David Howells
2023-03-30 17:55 ` Willem de Bruijn
2023-03-30 19:49 ` David Howells
2023-03-29 14:13 ` [RFC PATCH v2 17/48] ip, udp: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data David Howells
2023-03-29 14:13 ` [RFC PATCH v2 18/48] udp: Convert udp_sendpage() to use MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 19/48] af_unix: Support MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 20/48] af_unix: Make sendmsg(MSG_SPLICE_PAGES) copy unspliceable data David Howells
2023-03-29 14:13 ` [RFC PATCH v2 21/48] crypto: af_alg: Pin pages rather than ref'ing if appropriate David Howells
2023-03-29 14:13 ` [RFC PATCH v2 22/48] crypto: af_alg: Use netfs_extract_iter_to_sg() to create scatterlists David Howells
2023-03-29 14:13 ` [RFC PATCH v2 23/48] crypto: af_alg: Indent the loop in af_alg_sendmsg() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 24/48] crypto: af_alg: Support MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 25/48] crypto: af_alg: Convert af_alg_sendpage() to use MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 26/48] crypto: af_alg/hash: Support MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 27/48] splice, net: Use sendmsg(MSG_SPLICE_PAGES) rather than ->sendpage() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 28/48] splice: Reimplement splice_to_socket() to pass multiple bufs to sendmsg() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 29/48] Remove file->f_op->sendpage David Howells
2023-03-29 14:13 ` [RFC PATCH v2 30/48] siw: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage to transmit David Howells
2023-03-29 15:18 ` Bernard Metzler
2023-03-29 15:32 ` David Howells
2023-03-29 14:13 ` [RFC PATCH v2 31/48] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-03-29 14:13 ` [RFC PATCH v2 32/48] iscsi: " David Howells
2023-03-29 14:13 ` [RFC PATCH v2 33/48] iscsi: Assume "sendpage" is okay in iscsi_tcp_segment_map() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 34/48] tcp_bpf: Make tcp_bpf_sendpage() go through tcp_bpf_sendmsg(MSG_SPLICE_PAGES) David Howells
2023-03-29 14:13 ` [RFC PATCH v2 35/48] net: Use sendmsg(MSG_SPLICE_PAGES) not sendpage in skb_send_sock() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 36/48] algif: Remove hash_sendpage*() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 37/48] ceph: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() David Howells
2023-03-30 1:45 ` Xiubo Li
2023-03-30 6:48 ` David Howells
2023-03-31 13:05 ` Xiubo Li
2023-04-03 3:27 ` Xiubo Li
2023-04-03 8:32 ` David Howells
2023-04-10 0:38 ` Xiubo Li
2023-03-29 14:13 ` [RFC PATCH v2 38/48] rds: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage David Howells
2023-03-29 14:13 ` [RFC PATCH v2 39/48] dlm: " David Howells
2023-03-29 14:13 ` [RFC PATCH v2 40/48] sunrpc: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage David Howells
2023-03-29 15:28 ` Chuck Lever III
2023-03-29 19:58 ` David Howells
2023-03-30 9:29 ` David Howells
2023-03-30 9:41 ` David Howells
2023-03-30 13:16 ` Chuck Lever III
2023-03-30 13:01 ` David Howells
2023-03-30 13:16 ` David Howells
2023-03-30 13:27 ` Chuck Lever III
2023-03-30 14:26 ` David Howells
2023-03-30 16:36 ` Chuck Lever III
2023-04-14 14:41 ` Daire Byrne
2023-03-29 14:13 ` [RFC PATCH v2 41/48] sunrpc: Rely on TCP sendmsg + MSG_SPLICE_PAGES to copy unspliceable data David Howells
2023-03-29 14:13 ` [RFC PATCH v2 42/48] nvme: Use sendmsg(MSG_SPLICE_PAGES) rather then sendpage David Howells
2023-03-29 14:13 ` [RFC PATCH v2 43/48] kcm: " David Howells
2023-03-29 14:13 ` [RFC PATCH v2 44/48] smc: Drop smc_sendpage() in favour of smc_sendmsg() + MSG_SPLICE_PAGES David Howells
2023-03-29 14:13 ` [RFC PATCH v2 45/48] ocfs2: Use sendmsg(MSG_SPLICE_PAGES) rather than sendpage() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 46/48] drbd: Use sendmsg(MSG_SPLICE_PAGES) rather than sendmsg() David Howells
2023-03-29 14:13 ` [RFC PATCH v2 47/48] drdb: Send an entire bio in a single sendmsg David Howells
2023-03-29 14:13 ` [RFC PATCH v2 48/48] sock: Remove ->sendpage*() in favour of sendmsg(MSG_SPLICE_PAGES) David Howells
2023-03-29 14:23 ` Hannes Reinecke
2023-03-29 14:39 ` David Howells
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