From d9ba131d8f58c0d2ff5029e7002ab43f913b36f9 Mon Sep 17 00:00:00 2001 From: Trond Myklebust Date: Sun, 17 Jul 2011 18:11:30 -0400 Subject: [PATCH] SUNRPC: Support dynamic slot allocation for TCP connections Allow the number of available slots to grow with the TCP window size. Signed-off-by: Trond Myklebust --- include/linux/sunrpc/xprt.h | 9 ++++- net/sunrpc/xprt.c | 70 +++++++++++++++++++++++++++------ net/sunrpc/xprtrdma/transport.c | 1 + net/sunrpc/xprtsock.c | 49 +++++++++++++++++++---- 4 files changed, 109 insertions(+), 20 deletions(-) diff --git a/include/linux/sunrpc/xprt.h b/include/linux/sunrpc/xprt.h index 05047250f218..d02762d1de27 100644 --- a/include/linux/sunrpc/xprt.h +++ b/include/linux/sunrpc/xprt.h @@ -22,6 +22,7 @@ #define RPC_MIN_SLOT_TABLE (2U) #define RPC_DEF_SLOT_TABLE (16U) #define RPC_MAX_SLOT_TABLE (128U) +#define RPC_MAX_SLOT_TABLE_LIMIT (65536U) /* * This describes a timeout strategy @@ -168,7 +169,9 @@ struct rpc_xprt { struct rpc_wait_queue pending; /* requests in flight */ struct rpc_wait_queue backlog; /* waiting for slot */ struct list_head free; /* free slots */ - unsigned int max_reqs; /* total slots */ + unsigned int max_reqs; /* max number of slots */ + unsigned int min_reqs; /* min number of slots */ + atomic_t num_reqs; /* total slots */ unsigned long state; /* transport state */ unsigned char shutdown : 1, /* being shut down */ resvport : 1; /* use a reserved port */ @@ -281,7 +284,9 @@ void xprt_release_xprt_cong(struct rpc_xprt *xprt, struct rpc_task *task); void xprt_release(struct rpc_task *task); struct rpc_xprt * xprt_get(struct rpc_xprt *xprt); void xprt_put(struct rpc_xprt *xprt); -struct rpc_xprt * xprt_alloc(struct net *net, int size, int max_req); +struct rpc_xprt * xprt_alloc(struct net *net, size_t size, + unsigned int num_prealloc, + unsigned int max_req); void xprt_free(struct rpc_xprt *); static inline __be32 *xprt_skip_transport_header(struct rpc_xprt *xprt, __be32 *p) diff --git a/net/sunrpc/xprt.c b/net/sunrpc/xprt.c index ea7b3c16cddd..be85cf04a479 100644 --- a/net/sunrpc/xprt.c +++ b/net/sunrpc/xprt.c @@ -935,25 +935,66 @@ void xprt_transmit(struct rpc_task *task) spin_unlock_bh(&xprt->transport_lock); } +static struct rpc_rqst *xprt_dynamic_alloc_slot(struct rpc_xprt *xprt, gfp_t gfp_flags) +{ + struct rpc_rqst *req = ERR_PTR(-EAGAIN); + + if (!atomic_add_unless(&xprt->num_reqs, 1, xprt->max_reqs)) + goto out; + req = kzalloc(sizeof(struct rpc_rqst), gfp_flags); + if (req != NULL) + goto out; + atomic_dec(&xprt->num_reqs); + req = ERR_PTR(-ENOMEM); +out: + return req; +} + +static bool xprt_dynamic_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req) +{ + if (atomic_add_unless(&xprt->num_reqs, -1, xprt->min_reqs)) { + kfree(req); + return true; + } + return false; +} + static void xprt_alloc_slot(struct rpc_task *task) { struct rpc_xprt *xprt = task->tk_xprt; + struct rpc_rqst *req; - task->tk_status = 0; if (!list_empty(&xprt->free)) { - struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); - list_del_init(&req->rq_list); - task->tk_rqstp = req; - xprt_request_init(task, xprt); - return; + req = list_entry(xprt->free.next, struct rpc_rqst, rq_list); + list_del(&req->rq_list); + goto out_init_req; + } + req = xprt_dynamic_alloc_slot(xprt, GFP_NOWAIT); + if (!IS_ERR(req)) + goto out_init_req; + switch (PTR_ERR(req)) { + case -ENOMEM: + rpc_delay(task, HZ >> 2); + dprintk("RPC: dynamic allocation of request slot " + "failed! Retrying\n"); + break; + case -EAGAIN: + rpc_sleep_on(&xprt->backlog, task, NULL); + dprintk("RPC: waiting for request slot\n"); } - dprintk("RPC: waiting for request slot\n"); task->tk_status = -EAGAIN; - rpc_sleep_on(&xprt->backlog, task, NULL); + return; +out_init_req: + task->tk_status = 0; + task->tk_rqstp = req; + xprt_request_init(task, xprt); } static void xprt_free_slot(struct rpc_xprt *xprt, struct rpc_rqst *req) { + if (xprt_dynamic_free_slot(xprt, req)) + return; + memset(req, 0, sizeof(*req)); /* mark unused */ spin_lock(&xprt->reserve_lock); @@ -972,7 +1013,9 @@ static void xprt_free_all_slots(struct rpc_xprt *xprt) } } -struct rpc_xprt *xprt_alloc(struct net *net, int size, int num_prealloc) +struct rpc_xprt *xprt_alloc(struct net *net, size_t size, + unsigned int num_prealloc, + unsigned int max_alloc) { struct rpc_xprt *xprt; struct rpc_rqst *req; @@ -992,7 +1035,12 @@ struct rpc_xprt *xprt_alloc(struct net *net, int size, int num_prealloc) } if (i < num_prealloc) goto out_free; - xprt->max_reqs = num_prealloc; + if (max_alloc > num_prealloc) + xprt->max_reqs = max_alloc; + else + xprt->max_reqs = num_prealloc; + xprt->min_reqs = num_prealloc; + atomic_set(&xprt->num_reqs, num_prealloc); return xprt; @@ -1036,7 +1084,6 @@ void xprt_reserve(struct rpc_task *task) if (!xprt_lock_write(xprt, task)) return; - task->tk_status = -EIO; spin_lock(&xprt->reserve_lock); xprt_alloc_slot(task); spin_unlock(&xprt->reserve_lock); @@ -1057,6 +1104,7 @@ static void xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt) { struct rpc_rqst *req = task->tk_rqstp; + INIT_LIST_HEAD(&req->rq_list); req->rq_timeout = task->tk_client->cl_timeout->to_initval; req->rq_task = task; req->rq_xprt = xprt; diff --git a/net/sunrpc/xprtrdma/transport.c b/net/sunrpc/xprtrdma/transport.c index 674a49224450..b446e100286f 100644 --- a/net/sunrpc/xprtrdma/transport.c +++ b/net/sunrpc/xprtrdma/transport.c @@ -283,6 +283,7 @@ xprt_setup_rdma(struct xprt_create *args) } xprt = xprt_alloc(args->net, sizeof(struct rpcrdma_xprt), + xprt_rdma_slot_table_entries, xprt_rdma_slot_table_entries); if (xprt == NULL) { dprintk("RPC: %s: couldn't allocate rpcrdma_xprt\n", diff --git a/net/sunrpc/xprtsock.c b/net/sunrpc/xprtsock.c index adaa54c6a09a..d7f97ef26590 100644 --- a/net/sunrpc/xprtsock.c +++ b/net/sunrpc/xprtsock.c @@ -54,7 +54,8 @@ static void xs_close(struct rpc_xprt *xprt); * xprtsock tunables */ unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE; -unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE; +unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE; +unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE; unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT; unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT; @@ -75,6 +76,7 @@ static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO; static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE; static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE; +static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT; static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT; static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT; @@ -103,6 +105,15 @@ static ctl_table xs_tunables_table[] = { .extra1 = &min_slot_table_size, .extra2 = &max_slot_table_size }, + { + .procname = "tcp_max_slot_table_entries", + .data = &xprt_max_tcp_slot_table_entries, + .maxlen = sizeof(unsigned int), + .mode = 0644, + .proc_handler = proc_dointvec_minmax, + .extra1 = &min_slot_table_size, + .extra2 = &max_tcp_slot_table_limit + }, { .procname = "min_resvport", .data = &xprt_min_resvport, @@ -2491,7 +2502,8 @@ static int xs_init_anyaddr(const int family, struct sockaddr *sap) } static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args, - unsigned int slot_table_size) + unsigned int slot_table_size, + unsigned int max_slot_table_size) { struct rpc_xprt *xprt; struct sock_xprt *new; @@ -2501,7 +2513,8 @@ static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args, return ERR_PTR(-EBADF); } - xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size); + xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size, + max_slot_table_size); if (xprt == NULL) { dprintk("RPC: xs_setup_xprt: couldn't allocate " "rpc_xprt\n"); @@ -2543,7 +2556,8 @@ static struct rpc_xprt *xs_setup_local(struct xprt_create *args) struct rpc_xprt *xprt; struct rpc_xprt *ret; - xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries); + xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries, + xprt_max_tcp_slot_table_entries); if (IS_ERR(xprt)) return xprt; transport = container_of(xprt, struct sock_xprt, xprt); @@ -2607,7 +2621,8 @@ static struct rpc_xprt *xs_setup_udp(struct xprt_create *args) struct sock_xprt *transport; struct rpc_xprt *ret; - xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries); + xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries, + xprt_udp_slot_table_entries); if (IS_ERR(xprt)) return xprt; transport = container_of(xprt, struct sock_xprt, xprt); @@ -2683,7 +2698,8 @@ static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args) struct sock_xprt *transport; struct rpc_xprt *ret; - xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries); + xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries, + xprt_max_tcp_slot_table_entries); if (IS_ERR(xprt)) return xprt; transport = container_of(xprt, struct sock_xprt, xprt); @@ -2762,7 +2778,8 @@ static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args) */ return args->bc_xprt->xpt_bc_xprt; } - xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries); + xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries, + xprt_tcp_slot_table_entries); if (IS_ERR(xprt)) return xprt; transport = container_of(xprt, struct sock_xprt, xprt); @@ -2949,8 +2966,26 @@ static struct kernel_param_ops param_ops_slot_table_size = { #define param_check_slot_table_size(name, p) \ __param_check(name, p, unsigned int); +static int param_set_max_slot_table_size(const char *val, + const struct kernel_param *kp) +{ + return param_set_uint_minmax(val, kp, + RPC_MIN_SLOT_TABLE, + RPC_MAX_SLOT_TABLE_LIMIT); +} + +static struct kernel_param_ops param_ops_max_slot_table_size = { + .set = param_set_max_slot_table_size, + .get = param_get_uint, +}; + +#define param_check_max_slot_table_size(name, p) \ + __param_check(name, p, unsigned int); + module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries, slot_table_size, 0644); +module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries, + max_slot_table_size, 0644); module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries, slot_table_size, 0644); -- 2.34.1