diff options
| author | Paolo Abeni <pabeni@redhat.com> | 2023-10-23 13:44:39 -0700 |
|---|---|---|
| committer | Jakub Kicinski <kuba@kernel.org> | 2023-10-25 12:23:34 -0700 |
| commit | 0ffe8e74904027aa48d1f8bd52675c6f0a4c88d1 (patch) | |
| tree | 857be96578abfabad1f36ac8212c056f6534829b /net/mptcp | |
| parent | 5684ab1a0effbfeb706f47d85785f653005b97b1 (diff) | |
mptcp: use copy_from_iter helpers on transmit
The perf traces show an high cost for the MPTCP transmit path memcpy.
It turn out that the helper currently in use carries quite a bit
of unneeded overhead, e.g. to map/unmap the memory pages.
Moving to the 'copy_from_iter' variant removes such overhead and
additionally gains the no-cache support.
Reviewed-by: Mat Martineau <martineau@kernel.org>
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20231023-send-net-next-20231023-2-v1-6-9dc60939d371@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Diffstat (limited to 'net/mptcp')
| -rw-r--r-- | net/mptcp/protocol.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/net/mptcp/protocol.c b/net/mptcp/protocol.c index 7036e30c449f..5489f024dd7e 100644 --- a/net/mptcp/protocol.c +++ b/net/mptcp/protocol.c @@ -1760,6 +1760,18 @@ static int mptcp_sendmsg_fastopen(struct sock *sk, struct msghdr *msg, return ret; } +static int do_copy_data_nocache(struct sock *sk, int copy, + struct iov_iter *from, char *to) +{ + if (sk->sk_route_caps & NETIF_F_NOCACHE_COPY) { + if (!copy_from_iter_full_nocache(to, copy, from)) + return -EFAULT; + } else if (!copy_from_iter_full(to, copy, from)) { + return -EFAULT; + } + return 0; +} + static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) { struct mptcp_sock *msk = mptcp_sk(sk); @@ -1833,11 +1845,10 @@ static int mptcp_sendmsg(struct sock *sk, struct msghdr *msg, size_t len) if (!sk_wmem_schedule(sk, total_ts)) goto wait_for_memory; - if (copy_page_from_iter(dfrag->page, offset, psize, - &msg->msg_iter) != psize) { - ret = -EFAULT; + ret = do_copy_data_nocache(sk, psize, &msg->msg_iter, + page_address(dfrag->page) + offset); + if (ret) goto do_error; - } /* data successfully copied into the write queue */ sk_forward_alloc_add(sk, -total_ts); |