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tcp: Probe net.core.{r,w}mem_max, don't set SO_{RCV,SND}BUF if low

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If net.core.rmem_max and net.core.wmem_max sysctls have low values,
we can get bigger buffers by not trying to set them high -- the
kernel would lock their values to what we get.

Try, instead, to get bigger buffers by queueing as much as possible,
and if maximum values in tcp_wmem and tcp_rmem are bigger than this,
that will work.

While at it, drop QUICKACK option for non-spliced sockets, I set
that earlier by mistake.

Signed-off-by: Stefano Brivio <sbrivio@redhat.com>
This commit is contained in:
Stefano Brivio 2021-10-04 22:08:24 +02:00
parent e1a2e2780c
commit 683043e200
2 changed files with 26 additions and 16 deletions
Show stats Download patch file Download diff file Expand all files Collapse all files

34
tcp.c
View file

@ -807,14 +807,17 @@ static void tcp_get_sndbuf(struct tcp_tap_conn *conn)
* tcp_sock_set_bufsize() - Set SO_RCVBUF and SO_SNDBUF to maximum values
* @s: Socket, can be -1 to avoid check in the caller
*/
static void tcp_sock_set_bufsize(int s)
static void tcp_sock_set_bufsize(struct ctx *c, int s)
{
int v = INT_MAX / 2; /* Kernel clamps and rounds, no need to check */
if (s == -1)
return;
if (!c->tcp.low_rmem)
setsockopt(s, SOL_SOCKET, SO_RCVBUF, &v, sizeof(v));
if (!c->tcp.low_wmem)
setsockopt(s, SOL_SOCKET, SO_SNDBUF, &v, sizeof(v));
}
@ -1308,7 +1311,8 @@ static int tcp_send_to_tap(struct ctx *c, struct tcp_tap_conn *conn, int flags,
else
mss -= sizeof(struct ipv6hdr);
if (!conn->local && !tcp_rtt_dst_low(conn))
if (c->tcp.low_wmem &&
!conn->local && !tcp_rtt_dst_low(conn))
mss = MIN(mss, PAGE_SIZE);
else
mss = ROUND_DOWN(mss, PAGE_SIZE);
@ -1571,7 +1575,7 @@ static void tcp_conn_from_tap(struct ctx *c, int af, void *addr,
if (s < 0)
return;
tcp_sock_set_bufsize(s);
tcp_sock_set_bufsize(c, s);
if (af == AF_INET && addr4.sin_addr.s_addr == c->gw4)
addr4.sin_addr.s_addr = htonl(INADDR_LOOPBACK);
@ -2560,13 +2564,15 @@ static int tcp_splice_connect(struct ctx *c, struct tcp_splice_conn *conn,
.sin_addr = { .s_addr = htonl(INADDR_LOOPBACK) },
};
const struct sockaddr *sa;
int ret, one = 1;
socklen_t sl;
int ret;
conn->to = sock_conn;
if (s <= 0)
tcp_sock_set_bufsize(sock_conn);
tcp_sock_set_bufsize(c, sock_conn);
setsockopt(s, SOL_TCP, TCP_QUICKACK, &one, sizeof(one));
if (v6) {
sa = (struct sockaddr *)&addr6;
@ -3157,7 +3163,7 @@ static void tcp_sock_init_one(struct ctx *c, int ns, in_port_t port)
c->mode == MODE_PASTA ? BIND_EXT : BIND_ANY,
tref.u32);
if (s > 0)
tcp_sock_set_bufsize(s);
tcp_sock_set_bufsize(c, s);
else
s = -1;
@ -3170,7 +3176,7 @@ static void tcp_sock_init_one(struct ctx *c, int ns, in_port_t port)
s = sock_l4(c, AF_INET, IPPROTO_TCP, port,
BIND_LOOPBACK, tref.u32);
if (s > 0)
tcp_sock_set_bufsize(s);
tcp_sock_set_bufsize(c, s);
else
s = -1;
@ -3192,7 +3198,7 @@ static void tcp_sock_init_one(struct ctx *c, int ns, in_port_t port)
c->mode == MODE_PASTA ? BIND_EXT : BIND_ANY,
tref.u32);
if (s > 0)
tcp_sock_set_bufsize(s);
tcp_sock_set_bufsize(c, s);
else
s = -1;
@ -3205,7 +3211,7 @@ static void tcp_sock_init_one(struct ctx *c, int ns, in_port_t port)
s = sock_l4(c, AF_INET6, IPPROTO_TCP, port,
BIND_LOOPBACK, tref.u32);
if (s > 0)
tcp_sock_set_bufsize(s);
tcp_sock_set_bufsize(c, s);
else
s = -1;
@ -3287,7 +3293,7 @@ struct tcp_sock_refill_arg {
static int tcp_sock_refill(void *arg)
{
struct tcp_sock_refill_arg *a = (struct tcp_sock_refill_arg *)arg;
int i, *p4, *p6, one = 1;
int i, *p4, *p6;
if (a->ns) {
if (ns_enter(a->c->pasta_pid))
@ -3304,8 +3310,7 @@ static int tcp_sock_refill(void *arg)
break;
}
*p4 = socket(AF_INET, SOCK_STREAM | SOCK_NONBLOCK, IPPROTO_TCP);
setsockopt(*p4, SOL_TCP, TCP_QUICKACK, &one, sizeof(one));
tcp_sock_set_bufsize(*p4);
tcp_sock_set_bufsize(a->c, *p4);
}
for (i = 0; a->c->v6 && i < TCP_SOCK_POOL_SIZE; i++, p6++) {
@ -3314,8 +3319,7 @@ static int tcp_sock_refill(void *arg)
}
*p6 = socket(AF_INET6, SOCK_STREAM | SOCK_NONBLOCK,
IPPROTO_TCP);
setsockopt(*p6, SOL_TCP, TCP_QUICKACK, &one, sizeof(one));
tcp_sock_set_bufsize(*p6);
tcp_sock_set_bufsize(a->c, *p6);
}
return 0;
@ -3334,6 +3338,8 @@ int tcp_sock_init(struct ctx *c, struct timespec *now)
getrandom(&c->tcp.hash_secret, sizeof(c->tcp.hash_secret), GRND_RANDOM);
tcp_probe_mem(c);
for (port = 0; port < USHRT_MAX; port++) {
if (!bitmap_isset(c->tcp.port_to_tap, port))
continue;

4
tcp.h
View file

@ -51,6 +51,8 @@ union tcp_epoll_ref {
* @pipe_size: Size of pipes for spliced connections
* @refill_ts: Time of last refill operation for pools of sockets/pipes
* @port_detect_ts: Time of last TCP port detection/rebind, if enabled
* @low_wmem: Low probed net.core.wmem_max
* @low_rmem: Low probed net.core.rmem_max
*/
struct tcp_ctx {
uint64_t hash_secret[2];
@ -65,6 +67,8 @@ struct tcp_ctx {
size_t pipe_size;
struct timespec refill_ts;
struct timespec port_detect_ts;
int low_wmem;
int low_rmem;
};
#endif /* TCP_H */