Commit fe8e4649 authored Mar 06, 2014 by Ying Xue Committed by David S. Miller Mar 06, 2014

tipc: avoid to unnecessary process switch under non-block mode



When messages are received via tipc socket under non-block mode,
schedule_timeout() is called in tipc_wait_for_rcvmsg(), that is,
the process of receiving messages will be scheduled once although
timeout value passed to schedule_timeout() is 0. The same issue
exists in accept()/wait_for_accept(). To avoid this unnecessary
process switch, we only call schedule_timeout() if the timeout
value is non-zero.

Signed-off-by: Ying Xue <ying.xue@windriver.com>
Reviewed-by: Erik Hugne <erik.hugne@ericsson.com>
Reviewed-by: Jon Maloy <jon.maloy@ericsson.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

parent 4652edb7

net/tipc/socket.c

+2 −2

Original line number	Diff line number	Diff line
		@@ -997,7 +997,7 @@ static int tipc_wait_for_rcvmsg(struct socket *sock, long timeo)

		for (;;) {
		prepare_to_wait(sk_sleep(sk), &wait, TASK_INTERRUPTIBLE);
		if (skb_queue_empty(&sk->sk_receive_queue)) {
		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
		if (sock->state == SS_DISCONNECTING) {
		err = -ENOTCONN;
		break;
		@@ -1623,7 +1623,7 @@ static int tipc_wait_for_accept(struct socket *sock, long timeo)
		for (;;) {
		prepare_to_wait_exclusive(sk_sleep(sk), &wait,
		TASK_INTERRUPTIBLE);
		if (skb_queue_empty(&sk->sk_receive_queue)) {
		if (timeo && skb_queue_empty(&sk->sk_receive_queue)) {
		release_sock(sk);
		timeo = schedule_timeout(timeo);
		lock_sock(sk);