aboutsummaryrefslogtreecommitdiffstats
path: root/net/sunrpc/xprt.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/sunrpc/xprt.c')
-rw-r--r--net/sunrpc/xprt.c29
1 files changed, 19 insertions, 10 deletions
diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c
index e8d11bd6158e..0458319a1bdd 100644
--- a/net/sunrpc/xprt.c
+++ b/net/sunrpc/xprt.c
@@ -62,7 +62,23 @@ static inline void do_xprt_reserve(struct rpc_task *);
62static void xprt_connect_status(struct rpc_task *task); 62static void xprt_connect_status(struct rpc_task *task);
63static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *); 63static int __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
64 64
65static int xprt_clear_backlog(struct rpc_xprt *xprt); 65/*
66 * The transport code maintains an estimate on the maximum number of out-
67 * standing RPC requests, using a smoothed version of the congestion
68 * avoidance implemented in 44BSD. This is basically the Van Jacobson
69 * congestion algorithm: If a retransmit occurs, the congestion window is
70 * halved; otherwise, it is incremented by 1/cwnd when
71 *
72 * - a reply is received and
73 * - a full number of requests are outstanding and
74 * - the congestion window hasn't been updated recently.
75 */
76#define RPC_CWNDSHIFT (8U)
77#define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT)
78#define RPC_INITCWND RPC_CWNDSCALE
79#define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT)
80
81#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
66 82
67/** 83/**
68 * xprt_reserve_xprt - serialize write access to transports 84 * xprt_reserve_xprt - serialize write access to transports
@@ -850,7 +866,7 @@ void xprt_release(struct rpc_task *task)
850 866
851 spin_lock(&xprt->reserve_lock); 867 spin_lock(&xprt->reserve_lock);
852 list_add(&req->rq_list, &xprt->free); 868 list_add(&req->rq_list, &xprt->free);
853 xprt_clear_backlog(xprt); 869 rpc_wake_up_next(&xprt->backlog);
854 spin_unlock(&xprt->reserve_lock); 870 spin_unlock(&xprt->reserve_lock);
855} 871}
856 872
@@ -902,7 +918,6 @@ static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc
902 918
903 spin_lock_init(&xprt->transport_lock); 919 spin_lock_init(&xprt->transport_lock);
904 spin_lock_init(&xprt->reserve_lock); 920 spin_lock_init(&xprt->reserve_lock);
905 init_waitqueue_head(&xprt->cong_wait);
906 921
907 INIT_LIST_HEAD(&xprt->free); 922 INIT_LIST_HEAD(&xprt->free);
908 INIT_LIST_HEAD(&xprt->recv); 923 INIT_LIST_HEAD(&xprt->recv);
@@ -911,6 +926,7 @@ static struct rpc_xprt *xprt_setup(int proto, struct sockaddr_in *ap, struct rpc
911 xprt->timer.function = xprt_init_autodisconnect; 926 xprt->timer.function = xprt_init_autodisconnect;
912 xprt->timer.data = (unsigned long) xprt; 927 xprt->timer.data = (unsigned long) xprt;
913 xprt->last_used = jiffies; 928 xprt->last_used = jiffies;
929 xprt->cwnd = RPC_INITCWND;
914 930
915 rpc_init_wait_queue(&xprt->pending, "xprt_pending"); 931 rpc_init_wait_queue(&xprt->pending, "xprt_pending");
916 rpc_init_wait_queue(&xprt->sending, "xprt_sending"); 932 rpc_init_wait_queue(&xprt->sending, "xprt_sending");
@@ -955,16 +971,9 @@ static void xprt_shutdown(struct rpc_xprt *xprt)
955 rpc_wake_up(&xprt->resend); 971 rpc_wake_up(&xprt->resend);
956 xprt_wake_pending_tasks(xprt, -EIO); 972 xprt_wake_pending_tasks(xprt, -EIO);
957 rpc_wake_up(&xprt->backlog); 973 rpc_wake_up(&xprt->backlog);
958 wake_up(&xprt->cong_wait);
959 del_timer_sync(&xprt->timer); 974 del_timer_sync(&xprt->timer);
960} 975}
961 976
962static int xprt_clear_backlog(struct rpc_xprt *xprt) {
963 rpc_wake_up_next(&xprt->backlog);
964 wake_up(&xprt->cong_wait);
965 return 1;
966}
967
968/** 977/**
969 * xprt_destroy - destroy an RPC transport, killing off all requests. 978 * xprt_destroy - destroy an RPC transport, killing off all requests.
970 * @xprt: transport to destroy 979 * @xprt: transport to destroy