12a804698b
The next several patches introduce an API that allows transports to choose whether the RPC client provides congestion control or whether the transport itself provides it. The first method we abstract is the one that serializes access to the RPC transport to prevent the bytes from different requests from mingling together. This method provides proper request serialization and the opportunity to prevent new requests from being started because the transport is congested. The normal situation is for the transport to handle congestion control itself. Although NFS over UDP was first, it has been recognized after years of experience that having the transport provide congestion control is much better than doing it in the RPC client. Thus TCP, and probably every future transport implementation, will use the default method, xprt_lock_write, provided in xprt.c, which does not provide any kind of congestion control. UDP can continue using the xprt.c-provided Van Jacobson congestion avoidance implementation. Test-plan: Use WAN simulation to cause sporadic bursty packet loss. Look for significant regression in performance or client stability. Signed-off-by: Chuck Lever <cel@netapp.com> Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
319 lines
8.7 KiB
C
319 lines
8.7 KiB
C
/*
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* linux/include/linux/sunrpc/xprt.h
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*
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* Declarations for the RPC transport interface.
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*
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* Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
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*/
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#ifndef _LINUX_SUNRPC_XPRT_H
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#define _LINUX_SUNRPC_XPRT_H
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#include <linux/uio.h>
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#include <linux/socket.h>
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#include <linux/in.h>
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#include <linux/sunrpc/sched.h>
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#include <linux/sunrpc/xdr.h>
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/*
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* The transport code maintains an estimate on the maximum number of out-
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* standing RPC requests, using a smoothed version of the congestion
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* avoidance implemented in 44BSD. This is basically the Van Jacobson
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* congestion algorithm: If a retransmit occurs, the congestion window is
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* halved; otherwise, it is incremented by 1/cwnd when
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*
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* - a reply is received and
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* - a full number of requests are outstanding and
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* - the congestion window hasn't been updated recently.
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*
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* Upper procedures may check whether a request would block waiting for
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* a free RPC slot by using the RPC_CONGESTED() macro.
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*/
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extern unsigned int xprt_udp_slot_table_entries;
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extern unsigned int xprt_tcp_slot_table_entries;
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#define RPC_MIN_SLOT_TABLE (2U)
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#define RPC_DEF_SLOT_TABLE (16U)
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#define RPC_MAX_SLOT_TABLE (128U)
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#define RPC_CWNDSHIFT (8U)
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#define RPC_CWNDSCALE (1U << RPC_CWNDSHIFT)
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#define RPC_INITCWND RPC_CWNDSCALE
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#define RPC_MAXCWND(xprt) ((xprt)->max_reqs << RPC_CWNDSHIFT)
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#define RPCXPRT_CONGESTED(xprt) ((xprt)->cong >= (xprt)->cwnd)
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/* Default timeout values */
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#define RPC_MAX_UDP_TIMEOUT (60*HZ)
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#define RPC_MAX_TCP_TIMEOUT (600*HZ)
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/*
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* Wait duration for an RPC TCP connection to be established. Solaris
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* NFS over TCP uses 60 seconds, for example, which is in line with how
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* long a server takes to reboot.
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*/
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#define RPC_CONNECT_TIMEOUT (60*HZ)
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/*
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* Delay an arbitrary number of seconds before attempting to reconnect
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* after an error.
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*/
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#define RPC_REESTABLISH_TIMEOUT (15*HZ)
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/*
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* RPC transport idle timeout.
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*/
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#define RPC_IDLE_DISCONNECT_TIMEOUT (5*60*HZ)
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/*
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* RPC call and reply header size as number of 32bit words (verifier
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* size computed separately)
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*/
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#define RPC_CALLHDRSIZE 6
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#define RPC_REPHDRSIZE 4
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/*
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* This describes a timeout strategy
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*/
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struct rpc_timeout {
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unsigned long to_initval, /* initial timeout */
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to_maxval, /* max timeout */
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to_increment; /* if !exponential */
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unsigned int to_retries; /* max # of retries */
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unsigned char to_exponential;
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};
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/*
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* This describes a complete RPC request
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*/
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struct rpc_rqst {
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/*
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* This is the user-visible part
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*/
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struct rpc_xprt * rq_xprt; /* RPC client */
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struct xdr_buf rq_snd_buf; /* send buffer */
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struct xdr_buf rq_rcv_buf; /* recv buffer */
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/*
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* This is the private part
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*/
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struct rpc_task * rq_task; /* RPC task data */
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__u32 rq_xid; /* request XID */
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int rq_cong; /* has incremented xprt->cong */
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int rq_received; /* receive completed */
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u32 rq_seqno; /* gss seq no. used on req. */
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struct list_head rq_list;
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struct xdr_buf rq_private_buf; /* The receive buffer
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* used in the softirq.
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*/
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unsigned long rq_majortimeo; /* major timeout alarm */
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unsigned long rq_timeout; /* Current timeout value */
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unsigned int rq_retries; /* # of retries */
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/*
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* For authentication (e.g. auth_des)
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*/
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u32 rq_creddata[2];
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/*
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* Partial send handling
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*/
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u32 rq_bytes_sent; /* Bytes we have sent */
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unsigned long rq_xtime; /* when transmitted */
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int rq_ntrans;
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};
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#define rq_svec rq_snd_buf.head
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#define rq_slen rq_snd_buf.len
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struct rpc_task;
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struct rpc_xprt;
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struct rpc_xprt_ops {
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void (*set_buffer_size)(struct rpc_xprt *xprt);
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int (*reserve_xprt)(struct rpc_task *task);
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void (*connect)(struct rpc_task *task);
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int (*send_request)(struct rpc_task *task);
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void (*set_retrans_timeout)(struct rpc_task *task);
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void (*close)(struct rpc_xprt *xprt);
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void (*destroy)(struct rpc_xprt *xprt);
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};
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struct rpc_xprt {
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struct rpc_xprt_ops * ops; /* transport methods */
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struct socket * sock; /* BSD socket layer */
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struct sock * inet; /* INET layer */
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struct rpc_timeout timeout; /* timeout parms */
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struct sockaddr_in addr; /* server address */
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int prot; /* IP protocol */
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unsigned long cong; /* current congestion */
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unsigned long cwnd; /* congestion window */
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unsigned int rcvsize, /* transport rcv buffer size */
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sndsize; /* transport send buffer size */
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size_t max_payload; /* largest RPC payload size,
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in bytes */
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unsigned int tsh_size; /* size of transport specific
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header */
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struct rpc_wait_queue sending; /* requests waiting to send */
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struct rpc_wait_queue resend; /* requests waiting to resend */
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struct rpc_wait_queue pending; /* requests in flight */
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struct rpc_wait_queue backlog; /* waiting for slot */
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struct list_head free; /* free slots */
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struct rpc_rqst * slot; /* slot table storage */
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unsigned int max_reqs; /* total slots */
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unsigned long state; /* transport state */
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unsigned char shutdown : 1, /* being shut down */
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nocong : 1, /* no congestion control */
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resvport : 1; /* use a reserved port */
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/*
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* XID
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*/
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__u32 xid; /* Next XID value to use */
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/*
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* State of TCP reply receive stuff
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*/
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u32 tcp_recm, /* Fragment header */
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tcp_xid, /* Current XID */
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tcp_reclen, /* fragment length */
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tcp_offset; /* fragment offset */
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unsigned long tcp_copied, /* copied to request */
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tcp_flags;
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/*
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* Connection of transports
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*/
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struct work_struct connect_worker;
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unsigned short port;
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/*
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* Disconnection of idle transports
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*/
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struct work_struct task_cleanup;
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struct timer_list timer;
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unsigned long last_used;
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/*
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* Send stuff
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*/
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spinlock_t transport_lock; /* lock transport info */
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spinlock_t reserve_lock; /* lock slot table */
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struct rpc_task * snd_task; /* Task blocked in send */
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struct list_head recv;
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void (*old_data_ready)(struct sock *, int);
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void (*old_state_change)(struct sock *);
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void (*old_write_space)(struct sock *);
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wait_queue_head_t cong_wait;
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};
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#define XPRT_LAST_FRAG (1 << 0)
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#define XPRT_COPY_RECM (1 << 1)
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#define XPRT_COPY_XID (1 << 2)
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#define XPRT_COPY_DATA (1 << 3)
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#ifdef __KERNEL__
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/*
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* Transport operations used by ULPs
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*/
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struct rpc_xprt * xprt_create_proto(int proto, struct sockaddr_in *addr, struct rpc_timeout *to);
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void xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr);
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/*
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* Generic internal transport functions
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*/
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void xprt_connect(struct rpc_task *task);
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void xprt_reserve(struct rpc_task *task);
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int xprt_reserve_xprt(struct rpc_task *task);
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int xprt_reserve_xprt_cong(struct rpc_task *task);
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int xprt_prepare_transmit(struct rpc_task *task);
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void xprt_transmit(struct rpc_task *task);
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int xprt_adjust_timeout(struct rpc_rqst *req);
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void xprt_release(struct rpc_task *task);
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int xprt_destroy(struct rpc_xprt *xprt);
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static inline u32 *xprt_skip_transport_header(struct rpc_xprt *xprt, u32 *p)
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{
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return p + xprt->tsh_size;
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}
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/*
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* Transport switch helper functions
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*/
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void xprt_set_retrans_timeout_def(struct rpc_task *task);
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void xprt_set_retrans_timeout_rtt(struct rpc_task *task);
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void xprt_wake_pending_tasks(struct rpc_xprt *xprt, int status);
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void xprt_wait_for_buffer_space(struct rpc_task *task);
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void xprt_write_space(struct rpc_xprt *xprt);
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struct rpc_rqst * xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid);
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void xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied);
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void xprt_disconnect(struct rpc_xprt *xprt);
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/*
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* Socket transport setup operations
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*/
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int xs_setup_udp(struct rpc_xprt *xprt, struct rpc_timeout *to);
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int xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to);
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/*
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* Reserved bit positions in xprt->state
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*/
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#define XPRT_LOCKED (0)
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#define XPRT_CONNECTED (1)
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#define XPRT_CONNECTING (2)
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static inline void xprt_set_connected(struct rpc_xprt *xprt)
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{
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set_bit(XPRT_CONNECTED, &xprt->state);
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}
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static inline void xprt_clear_connected(struct rpc_xprt *xprt)
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{
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clear_bit(XPRT_CONNECTED, &xprt->state);
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}
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static inline int xprt_connected(struct rpc_xprt *xprt)
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{
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return test_bit(XPRT_CONNECTED, &xprt->state);
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}
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static inline int xprt_test_and_set_connected(struct rpc_xprt *xprt)
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{
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return test_and_set_bit(XPRT_CONNECTED, &xprt->state);
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}
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static inline int xprt_test_and_clear_connected(struct rpc_xprt *xprt)
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{
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return test_and_clear_bit(XPRT_CONNECTED, &xprt->state);
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}
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static inline void xprt_clear_connecting(struct rpc_xprt *xprt)
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{
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smp_mb__before_clear_bit();
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clear_bit(XPRT_CONNECTING, &xprt->state);
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smp_mb__after_clear_bit();
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}
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static inline int xprt_connecting(struct rpc_xprt *xprt)
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{
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return test_bit(XPRT_CONNECTING, &xprt->state);
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}
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static inline int xprt_test_and_set_connecting(struct rpc_xprt *xprt)
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{
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return test_and_set_bit(XPRT_CONNECTING, &xprt->state);
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}
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#endif /* __KERNEL__*/
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#endif /* _LINUX_SUNRPC_XPRT_H */
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