From 484652c6322800b32510d6c74d8fc4c8027a106e Mon Sep 17 00:00:00 2001 From: David Gibson Date: Tue, 13 Sep 2022 16:37:43 +1000 Subject: udp: Don't pre-initialize msghdr array In udp_tap_handler() the array of msghdr structures, mm[], is initialized to zero. Since UIO_MAXIOV is 1024, this can be quite a large zero, which is expensive if we only end up using a few of its entries. It also makes it less obvious how we're setting all the control fields at the point we actually invoke sendmmsg(). Rather than pre-initializing it, just initialize each element as we use it. Signed-off-by: David Gibson --- udp.c | 6 +++++- 1 file changed, 5 insertions(+), 1 deletion(-) diff --git a/udp.c b/udp.c index c4ebecc..864e7b2 100644 --- a/udp.c +++ b/udp.c @@ -968,7 +968,7 @@ void udp_sock_handler(const struct ctx *c, union epoll_ref ref, uint32_t events, int udp_tap_handler(struct ctx *c, int af, const void *addr, const struct pool *p, const struct timespec *now) { - struct mmsghdr mm[UIO_MAXIOV] = { 0 }; + struct mmsghdr mm[UIO_MAXIOV]; struct iovec m[UIO_MAXIOV]; struct sockaddr_in6 s_in6; struct sockaddr_in s_in; @@ -1087,6 +1087,10 @@ int udp_tap_handler(struct ctx *c, int af, const void *addr, mm[i].msg_hdr.msg_iov = m + i; mm[i].msg_hdr.msg_iovlen = 1; + mm[i].msg_hdr.msg_control = NULL; + mm[i].msg_hdr.msg_controllen = 0; + mm[i].msg_hdr.msg_flags = 0; + count++; } -- cgit v1.2.3