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>
This commit is contained in:
Jon Maloy
David S. Miller
parent
232d07b74a
commit
eb929a91b2
@ -74,7 +74,6 @@ struct tipc_member {
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u16 bc_rcv_nxt;
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u16 bc_syncpt;
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u16 bc_acked;
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bool usr_pending;
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};
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struct tipc_group {
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@ -96,11 +95,27 @@ struct tipc_group {
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u16 bc_ackers;
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bool loopback;
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bool events;
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bool open;
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};
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static void tipc_group_proto_xmit(struct tipc_group *grp, struct tipc_member *m,
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int mtyp, struct sk_buff_head *xmitq);
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bool tipc_group_is_open(struct tipc_group *grp)
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{
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return grp->open;
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}
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static void tipc_group_open(struct tipc_member *m, bool *wakeup)
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{
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*wakeup = false;
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if (list_empty(&m->small_win))
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return;
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list_del_init(&m->small_win);
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m->group->open = true;
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*wakeup = true;
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}
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static void tipc_group_decr_active(struct tipc_group *grp,
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struct tipc_member *m)
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{
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@ -406,20 +421,20 @@ bool tipc_group_cong(struct tipc_group *grp, u32 dnode, u32 dport,
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int adv, state;
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m = tipc_group_find_dest(grp, dnode, dport);
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*mbr = m;
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if (!m)
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if (!tipc_group_is_receiver(m)) {
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*mbr = NULL;
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return false;
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if (m->usr_pending)
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return true;
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}
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*mbr = m;
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if (m->window >= len)
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return false;
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m->usr_pending = true;
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grp->open = false;
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/* If not fully advertised, do it now to prevent mutual blocking */
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adv = m->advertised;
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state = m->state;
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if (state < MBR_JOINED)
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return true;
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if (state == MBR_JOINED && adv == ADV_IDLE)
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return true;
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if (state == MBR_ACTIVE && adv == ADV_ACTIVE)
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@ -437,9 +452,10 @@ bool tipc_group_bc_cong(struct tipc_group *grp, int len)
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struct tipc_member *m = NULL;
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/* If prev bcast was replicast, reject until all receivers have acked */
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if (grp->bc_ackers)
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if (grp->bc_ackers) {
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grp->open = false;
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return true;
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}
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if (list_empty(&grp->small_win))
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return false;
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@ -754,9 +770,7 @@ void tipc_group_proto_rcv(struct tipc_group *grp, bool *usr_wakeup,
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/* Member can be taken into service */
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m->state = MBR_JOINED;
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*usr_wakeup = true;
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m->usr_pending = false;
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list_del_init(&m->small_win);
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tipc_group_open(m, usr_wakeup);
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tipc_group_update_member(m, 0);
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tipc_group_proto_xmit(grp, m, GRP_ADV_MSG, xmitq);
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tipc_group_create_event(grp, m, TIPC_PUBLISHED,
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@ -767,8 +781,7 @@ void tipc_group_proto_rcv(struct tipc_group *grp, bool *usr_wakeup,
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return;
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m->bc_syncpt = msg_grp_bc_syncpt(hdr);
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list_del_init(&m->list);
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list_del_init(&m->small_win);
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*usr_wakeup = true;
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tipc_group_open(m, usr_wakeup);
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tipc_group_decr_active(grp, m);
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m->state = MBR_LEAVING;
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tipc_group_create_event(grp, m, TIPC_WITHDRAWN,
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@ -778,26 +791,25 @@ void tipc_group_proto_rcv(struct tipc_group *grp, bool *usr_wakeup,
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if (!m)
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return;
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m->window += msg_adv_win(hdr);
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*usr_wakeup = m->usr_pending;
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m->usr_pending = false;
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list_del_init(&m->small_win);
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tipc_group_open(m, usr_wakeup);
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return;
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case GRP_ACK_MSG:
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if (!m)
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return;
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m->bc_acked = msg_grp_bc_acked(hdr);
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if (--grp->bc_ackers)
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break;
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return;
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list_del_init(&m->small_win);
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m->group->open = true;
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*usr_wakeup = true;
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m->usr_pending = false;
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tipc_group_update_member(m, 0);
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return;
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case GRP_RECLAIM_MSG:
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if (!m)
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return;
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*usr_wakeup = m->usr_pending;
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m->usr_pending = false;
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tipc_group_proto_xmit(grp, m, GRP_REMIT_MSG, xmitq);
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m->window = ADV_IDLE;
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tipc_group_open(m, usr_wakeup);
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return;
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case GRP_REMIT_MSG:
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if (!m || m->state != MBR_RECLAIMING)
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@ -883,9 +895,7 @@ void tipc_group_member_evt(struct tipc_group *grp,
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/* Member can be taken into service */
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m->instance = instance;
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m->state = MBR_JOINED;
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*usr_wakeup = true;
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m->usr_pending = false;
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list_del_init(&m->small_win);
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tipc_group_open(m, usr_wakeup);
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tipc_group_update_member(m, 0);
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tipc_group_proto_xmit(grp, m, GRP_JOIN_MSG, xmitq);
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tipc_group_create_event(grp, m, TIPC_PUBLISHED,
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@ -895,12 +905,10 @@ void tipc_group_member_evt(struct tipc_group *grp,
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if (!m)
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break;
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*usr_wakeup = true;
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m->usr_pending = false;
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tipc_group_decr_active(grp, m);
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m->state = MBR_LEAVING;
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list_del_init(&m->list);
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list_del_init(&m->small_win);
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tipc_group_open(m, usr_wakeup);
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/* Only send event if no LEAVE message can be expected */
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if (!tipc_node_is_up(net, node))
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@ -67,9 +67,9 @@ void tipc_group_update_bc_members(struct tipc_group *grp, int len, bool ack);
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bool tipc_group_cong(struct tipc_group *grp, u32 dnode, u32 dport,
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int len, struct tipc_member **m);
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bool tipc_group_bc_cong(struct tipc_group *grp, int len);
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bool tipc_group_is_open(struct tipc_group *grp);
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void tipc_group_update_rcv_win(struct tipc_group *grp, int blks, u32 node,
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u32 port, struct sk_buff_head *xmitq);
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u16 tipc_group_bc_snd_nxt(struct tipc_group *grp);
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void tipc_group_update_member(struct tipc_member *m, int len);
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int tipc_group_size(struct tipc_group *grp);
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#endif
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@ -715,7 +715,7 @@ static unsigned int tipc_poll(struct file *file, struct socket *sock,
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{
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struct sock *sk = sock->sk;
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struct tipc_sock *tsk = tipc_sk(sk);
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struct tipc_group *grp = tsk->group;
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struct tipc_group *grp;
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u32 revents = 0;
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sock_poll_wait(file, sk_sleep(sk), wait);
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@ -736,9 +736,9 @@ static unsigned int tipc_poll(struct file *file, struct socket *sock,
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revents |= POLLIN | POLLRDNORM;
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break;
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case TIPC_OPEN:
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if (!grp || tipc_group_size(grp))
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if (!tsk->cong_link_cnt)
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revents |= POLLOUT;
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grp = tsk->group;
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if ((!grp || tipc_group_is_open(grp)) && !tsk->cong_link_cnt)
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revents |= POLLOUT;
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if (!tipc_sk_type_connectionless(sk))
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break;
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if (skb_queue_empty(&sk->sk_receive_queue))
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