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authorJon Maloy <jon.maloy@ericsson.com>2018-01-08 23:03:31 +0300
committerDavid S. Miller <davem@davemloft.net>2018-01-09 20:35:58 +0300
commiteb929a91b213d2a72c5a8b4af9a1acf63bfb8287 (patch)
tree9562eb2a8fc216296ce455d4b124ada6b13ca965 /net/tipc/socket.c
parent232d07b74a33b9f5d48516dc1d8ce41723ada593 (diff)
downloadlinux-eb929a91b213d2a72c5a8b4af9a1acf63bfb8287.tar.xz
tipc: improve poll() for group member socket
The current criteria for returning POLLOUT from a group member socket is too simplistic. It basically returns POLLOUT as soon as the group has external destinations, something obviously leading to a lot of spinning during destination congestion situations. At the same time, the internal congestion handling is unnecessarily complex. We now change this as follows. - We introduce an 'open' flag in struct tipc_group. This flag is used only to help poll() get the setting of POLLOUT right, and *not* for congeston handling as such. This means that a user can choose to ignore an EAGAIN for a destination and go on sending messages to other destinations in the group if he wants to. - The flag is set to false every time we return EAGAIN on a send call. - The flag is set to true every time any member, i.e., not necessarily the member that caused EAGAIN, is removed from the small_win list. - We remove the group member 'usr_pending' flag. The size of the send window and presence in the 'small_win' list is sufficient criteria for recognizing congestion. This solution seems to be a reasonable compromise between 'anycast', which is normally not waiting for POLLOUT for a specific destination, and the other three send modes, which are. Acked-by: Ying Xue <ying.xue@windriver.com> Signed-off-by: Jon Maloy <jon.maloy@ericsson.com> Signed-off-by: David S. Miller <davem@davemloft.net>
Diffstat (limited to 'net/tipc/socket.c')
-rw-r--r--net/tipc/socket.c8
1 files changed, 4 insertions, 4 deletions
diff --git a/net/tipc/socket.c b/net/tipc/socket.c
index b24dab3996c9..1f236271766c 100644
--- a/net/tipc/socket.c
+++ b/net/tipc/socket.c
@@ -715,7 +715,7 @@ static unsigned int tipc_poll(struct file *file, struct socket *sock,
{
struct sock *sk = sock->sk;
struct tipc_sock *tsk = tipc_sk(sk);
- struct tipc_group *grp = tsk->group;
+ struct tipc_group *grp;
u32 revents = 0;
sock_poll_wait(file, sk_sleep(sk), wait);
@@ -736,9 +736,9 @@ static unsigned int tipc_poll(struct file *file, struct socket *sock,
revents |= POLLIN | POLLRDNORM;
break;
case TIPC_OPEN:
- if (!grp || tipc_group_size(grp))
- if (!tsk->cong_link_cnt)
- revents |= POLLOUT;
+ grp = tsk->group;
+ if ((!grp || tipc_group_is_open(grp)) && !tsk->cong_link_cnt)
+ revents |= POLLOUT;
if (!tipc_sk_type_connectionless(sk))
break;
if (skb_queue_empty(&sk->sk_receive_queue))