xprtrdma: Pre-allocate backward rpc_rqst and send/receive buffers

xprtrdma's backward direction send and receive buffers are the same
size as the forechannel's inline threshold, and must be pre-
registered.

The consumer has no control over which receive buffer the adapter
chooses to catch an incoming backwards-direction call. Any receive
buffer can be used for either a forward reply or a backward call.
Thus both types of RPC message must all be the same size.

Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
Reviewed-by: Sagi Grimberg <sagig@mellanox.com>
Tested-By: Devesh Sharma <devesh.sharma@avagotech.com>
Signed-off-by: Anna Schumaker <Anna.Schumaker@Netapp.com>
This commit is contained in:
Chuck Lever 2015-10-24 17:27:43 -04:00 committed by Anna Schumaker
parent 42e5c3e272
commit f531a5dbc4
5 changed files with 309 additions and 12 deletions

View File

@ -5,3 +5,4 @@ rpcrdma-y := transport.o rpc_rdma.o verbs.o \
svc_rdma.o svc_rdma_transport.o \
svc_rdma_marshal.o svc_rdma_sendto.o svc_rdma_recvfrom.o \
module.o
rpcrdma-$(CONFIG_SUNRPC_BACKCHANNEL) += backchannel.o

View File

@ -0,0 +1,206 @@
/*
* Copyright (c) 2015 Oracle. All rights reserved.
*
* Support for backward direction RPCs on RPC/RDMA.
*/
#include <linux/module.h>
#include "xprt_rdma.h"
#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
# define RPCDBG_FACILITY RPCDBG_TRANS
#endif
static void rpcrdma_bc_free_rqst(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
struct rpcrdma_buffer *buf = &r_xprt->rx_buf;
struct rpcrdma_req *req = rpcr_to_rdmar(rqst);
spin_lock(&buf->rb_reqslock);
list_del(&req->rl_all);
spin_unlock(&buf->rb_reqslock);
rpcrdma_destroy_req(&r_xprt->rx_ia, req);
kfree(rqst);
}
static int rpcrdma_bc_setup_rqst(struct rpcrdma_xprt *r_xprt,
struct rpc_rqst *rqst)
{
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
struct rpcrdma_regbuf *rb;
struct rpcrdma_req *req;
struct xdr_buf *buf;
size_t size;
req = rpcrdma_create_req(r_xprt);
if (!req)
return -ENOMEM;
req->rl_backchannel = true;
size = RPCRDMA_INLINE_WRITE_THRESHOLD(rqst);
rb = rpcrdma_alloc_regbuf(ia, size, GFP_KERNEL);
if (IS_ERR(rb))
goto out_fail;
req->rl_rdmabuf = rb;
size += RPCRDMA_INLINE_READ_THRESHOLD(rqst);
rb = rpcrdma_alloc_regbuf(ia, size, GFP_KERNEL);
if (IS_ERR(rb))
goto out_fail;
rb->rg_owner = req;
req->rl_sendbuf = rb;
/* so that rpcr_to_rdmar works when receiving a request */
rqst->rq_buffer = (void *)req->rl_sendbuf->rg_base;
buf = &rqst->rq_snd_buf;
buf->head[0].iov_base = rqst->rq_buffer;
buf->head[0].iov_len = 0;
buf->tail[0].iov_base = NULL;
buf->tail[0].iov_len = 0;
buf->page_len = 0;
buf->len = 0;
buf->buflen = size;
return 0;
out_fail:
rpcrdma_bc_free_rqst(r_xprt, rqst);
return -ENOMEM;
}
/* Allocate and add receive buffers to the rpcrdma_buffer's
* existing list of rep's. These are released when the
* transport is destroyed.
*/
static int rpcrdma_bc_setup_reps(struct rpcrdma_xprt *r_xprt,
unsigned int count)
{
struct rpcrdma_buffer *buffers = &r_xprt->rx_buf;
struct rpcrdma_rep *rep;
unsigned long flags;
int rc = 0;
while (count--) {
rep = rpcrdma_create_rep(r_xprt);
if (IS_ERR(rep)) {
pr_err("RPC: %s: reply buffer alloc failed\n",
__func__);
rc = PTR_ERR(rep);
break;
}
spin_lock_irqsave(&buffers->rb_lock, flags);
list_add(&rep->rr_list, &buffers->rb_recv_bufs);
spin_unlock_irqrestore(&buffers->rb_lock, flags);
}
return rc;
}
/**
* xprt_rdma_bc_setup - Pre-allocate resources for handling backchannel requests
* @xprt: transport associated with these backchannel resources
* @reqs: number of concurrent incoming requests to expect
*
* Returns 0 on success; otherwise a negative errno
*/
int xprt_rdma_bc_setup(struct rpc_xprt *xprt, unsigned int reqs)
{
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
struct rpc_rqst *rqst;
unsigned int i;
int rc;
/* The backchannel reply path returns each rpc_rqst to the
* bc_pa_list _after_ the reply is sent. If the server is
* faster than the client, it can send another backward
* direction request before the rpc_rqst is returned to the
* list. The client rejects the request in this case.
*
* Twice as many rpc_rqsts are prepared to ensure there is
* always an rpc_rqst available as soon as a reply is sent.
*/
for (i = 0; i < (reqs << 1); i++) {
rqst = kzalloc(sizeof(*rqst), GFP_KERNEL);
if (!rqst) {
pr_err("RPC: %s: Failed to create bc rpc_rqst\n",
__func__);
goto out_free;
}
rqst->rq_xprt = &r_xprt->rx_xprt;
INIT_LIST_HEAD(&rqst->rq_list);
INIT_LIST_HEAD(&rqst->rq_bc_list);
if (rpcrdma_bc_setup_rqst(r_xprt, rqst))
goto out_free;
spin_lock_bh(&xprt->bc_pa_lock);
list_add(&rqst->rq_bc_pa_list, &xprt->bc_pa_list);
spin_unlock_bh(&xprt->bc_pa_lock);
}
rc = rpcrdma_bc_setup_reps(r_xprt, reqs);
if (rc)
goto out_free;
rc = rpcrdma_ep_post_extra_recv(r_xprt, reqs);
if (rc)
goto out_free;
buffer->rb_bc_srv_max_requests = reqs;
request_module("svcrdma");
return 0;
out_free:
xprt_rdma_bc_destroy(xprt, reqs);
pr_err("RPC: %s: setup backchannel transport failed\n", __func__);
return -ENOMEM;
}
/**
* xprt_rdma_bc_destroy - Release resources for handling backchannel requests
* @xprt: transport associated with these backchannel resources
* @reqs: number of incoming requests to destroy; ignored
*/
void xprt_rdma_bc_destroy(struct rpc_xprt *xprt, unsigned int reqs)
{
struct rpcrdma_xprt *r_xprt = rpcx_to_rdmax(xprt);
struct rpc_rqst *rqst, *tmp;
spin_lock_bh(&xprt->bc_pa_lock);
list_for_each_entry_safe(rqst, tmp, &xprt->bc_pa_list, rq_bc_pa_list) {
list_del(&rqst->rq_bc_pa_list);
spin_unlock_bh(&xprt->bc_pa_lock);
rpcrdma_bc_free_rqst(r_xprt, rqst);
spin_lock_bh(&xprt->bc_pa_lock);
}
spin_unlock_bh(&xprt->bc_pa_lock);
}
/**
* xprt_rdma_bc_free_rqst - Release a backchannel rqst
* @rqst: request to release
*/
void xprt_rdma_bc_free_rqst(struct rpc_rqst *rqst)
{
struct rpc_xprt *xprt = rqst->rq_xprt;
smp_mb__before_atomic();
WARN_ON_ONCE(!test_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state));
clear_bit(RPC_BC_PA_IN_USE, &rqst->rq_bc_pa_state);
smp_mb__after_atomic();
spin_lock_bh(&xprt->bc_pa_lock);
list_add_tail(&rqst->rq_bc_pa_list, &xprt->bc_pa_list);
spin_unlock_bh(&xprt->bc_pa_lock);
}

View File

@ -705,7 +705,12 @@ static struct rpc_xprt_ops xprt_rdma_procs = {
.print_stats = xprt_rdma_print_stats,
.enable_swap = xprt_rdma_enable_swap,
.disable_swap = xprt_rdma_disable_swap,
.inject_disconnect = xprt_rdma_inject_disconnect
.inject_disconnect = xprt_rdma_inject_disconnect,
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
.bc_setup = xprt_rdma_bc_setup,
.bc_free_rqst = xprt_rdma_bc_free_rqst,
.bc_destroy = xprt_rdma_bc_destroy,
#endif
};
static struct xprt_class xprt_rdma = {

View File

@ -831,7 +831,21 @@ retry:
}
rc = ep->rep_connected;
} else {
struct rpcrdma_xprt *r_xprt;
unsigned int extras;
dprintk("RPC: %s: connected\n", __func__);
r_xprt = container_of(ia, struct rpcrdma_xprt, rx_ia);
extras = r_xprt->rx_buf.rb_bc_srv_max_requests;
if (extras) {
rc = rpcrdma_ep_post_extra_recv(r_xprt, extras);
if (rc)
pr_warn("%s: rpcrdma_ep_post_extra_recv: %i\n",
__func__, rc);
rc = 0;
}
}
out:
@ -868,20 +882,25 @@ rpcrdma_ep_disconnect(struct rpcrdma_ep *ep, struct rpcrdma_ia *ia)
}
}
static struct rpcrdma_req *
struct rpcrdma_req *
rpcrdma_create_req(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_buffer *buffer = &r_xprt->rx_buf;
struct rpcrdma_req *req;
req = kzalloc(sizeof(*req), GFP_KERNEL);
if (req == NULL)
return ERR_PTR(-ENOMEM);
INIT_LIST_HEAD(&req->rl_free);
spin_lock(&buffer->rb_reqslock);
list_add(&req->rl_all, &buffer->rb_allreqs);
spin_unlock(&buffer->rb_reqslock);
req->rl_buffer = &r_xprt->rx_buf;
return req;
}
static struct rpcrdma_rep *
struct rpcrdma_rep *
rpcrdma_create_rep(struct rpcrdma_xprt *r_xprt)
{
struct rpcrdma_create_data_internal *cdata = &r_xprt->rx_data;
@ -920,6 +939,7 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
int i, rc;
buf->rb_max_requests = r_xprt->rx_data.max_requests;
buf->rb_bc_srv_max_requests = 0;
spin_lock_init(&buf->rb_lock);
rc = ia->ri_ops->ro_init(r_xprt);
@ -927,6 +947,8 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
goto out;
INIT_LIST_HEAD(&buf->rb_send_bufs);
INIT_LIST_HEAD(&buf->rb_allreqs);
spin_lock_init(&buf->rb_reqslock);
for (i = 0; i < buf->rb_max_requests; i++) {
struct rpcrdma_req *req;
@ -937,6 +959,7 @@ rpcrdma_buffer_create(struct rpcrdma_xprt *r_xprt)
rc = PTR_ERR(req);
goto out;
}
req->rl_backchannel = false;
list_add(&req->rl_free, &buf->rb_send_bufs);
}
@ -985,19 +1008,13 @@ rpcrdma_buffer_get_rep_locked(struct rpcrdma_buffer *buf)
static void
rpcrdma_destroy_rep(struct rpcrdma_ia *ia, struct rpcrdma_rep *rep)
{
if (!rep)
return;
rpcrdma_free_regbuf(ia, rep->rr_rdmabuf);
kfree(rep);
}
static void
void
rpcrdma_destroy_req(struct rpcrdma_ia *ia, struct rpcrdma_req *req)
{
if (!req)
return;
rpcrdma_free_regbuf(ia, req->rl_sendbuf);
rpcrdma_free_regbuf(ia, req->rl_rdmabuf);
kfree(req);
@ -1015,12 +1032,19 @@ rpcrdma_buffer_destroy(struct rpcrdma_buffer *buf)
rpcrdma_destroy_rep(ia, rep);
}
while (!list_empty(&buf->rb_send_bufs)) {
spin_lock(&buf->rb_reqslock);
while (!list_empty(&buf->rb_allreqs)) {
struct rpcrdma_req *req;
req = rpcrdma_buffer_get_req_locked(buf);
req = list_first_entry(&buf->rb_allreqs,
struct rpcrdma_req, rl_all);
list_del(&req->rl_all);
spin_unlock(&buf->rb_reqslock);
rpcrdma_destroy_req(ia, req);
spin_lock(&buf->rb_reqslock);
}
spin_unlock(&buf->rb_reqslock);
ia->ri_ops->ro_destroy(buf);
}
@ -1288,6 +1312,47 @@ rpcrdma_ep_post_recv(struct rpcrdma_ia *ia,
return rc;
}
/**
* rpcrdma_ep_post_extra_recv - Post buffers for incoming backchannel requests
* @r_xprt: transport associated with these backchannel resources
* @min_reqs: minimum number of incoming requests expected
*
* Returns zero if all requested buffers were posted, or a negative errno.
*/
int
rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *r_xprt, unsigned int count)
{
struct rpcrdma_buffer *buffers = &r_xprt->rx_buf;
struct rpcrdma_ia *ia = &r_xprt->rx_ia;
struct rpcrdma_ep *ep = &r_xprt->rx_ep;
struct rpcrdma_rep *rep;
unsigned long flags;
int rc;
while (count--) {
spin_lock_irqsave(&buffers->rb_lock, flags);
if (list_empty(&buffers->rb_recv_bufs))
goto out_reqbuf;
rep = rpcrdma_buffer_get_rep_locked(buffers);
spin_unlock_irqrestore(&buffers->rb_lock, flags);
rc = rpcrdma_ep_post_recv(ia, ep, rep);
if (rc)
goto out_rc;
}
return 0;
out_reqbuf:
spin_unlock_irqrestore(&buffers->rb_lock, flags);
pr_warn("%s: no extra receive buffers\n", __func__);
return -ENOMEM;
out_rc:
rpcrdma_recv_buffer_put(rep);
return rc;
}
/* How many chunk list items fit within our inline buffers?
*/
unsigned int

View File

@ -263,6 +263,9 @@ struct rpcrdma_req {
struct rpcrdma_regbuf *rl_rdmabuf;
struct rpcrdma_regbuf *rl_sendbuf;
struct rpcrdma_mr_seg rl_segments[RPCRDMA_MAX_SEGS];
struct list_head rl_all;
bool rl_backchannel;
};
static inline struct rpcrdma_req *
@ -291,6 +294,10 @@ struct rpcrdma_buffer {
struct list_head rb_send_bufs;
struct list_head rb_recv_bufs;
u32 rb_max_requests;
u32 rb_bc_srv_max_requests;
spinlock_t rb_reqslock; /* protect rb_allreqs */
struct list_head rb_allreqs;
};
#define rdmab_to_ia(b) (&container_of((b), struct rpcrdma_xprt, rx_buf)->rx_ia)
@ -411,6 +418,9 @@ int rpcrdma_ep_post_recv(struct rpcrdma_ia *, struct rpcrdma_ep *,
/*
* Buffer calls - xprtrdma/verbs.c
*/
struct rpcrdma_req *rpcrdma_create_req(struct rpcrdma_xprt *);
struct rpcrdma_rep *rpcrdma_create_rep(struct rpcrdma_xprt *);
void rpcrdma_destroy_req(struct rpcrdma_ia *, struct rpcrdma_req *);
int rpcrdma_buffer_create(struct rpcrdma_xprt *);
void rpcrdma_buffer_destroy(struct rpcrdma_buffer *);
@ -427,6 +437,7 @@ void rpcrdma_free_regbuf(struct rpcrdma_ia *,
struct rpcrdma_regbuf *);
unsigned int rpcrdma_max_segments(struct rpcrdma_xprt *);
int rpcrdma_ep_post_extra_recv(struct rpcrdma_xprt *, unsigned int);
int frwr_alloc_recovery_wq(void);
void frwr_destroy_recovery_wq(void);
@ -494,6 +505,15 @@ int rpcrdma_marshal_req(struct rpc_rqst *);
int xprt_rdma_init(void);
void xprt_rdma_cleanup(void);
/* Backchannel calls - xprtrdma/backchannel.c
*/
#if defined(CONFIG_SUNRPC_BACKCHANNEL)
int xprt_rdma_bc_setup(struct rpc_xprt *, unsigned int);
int rpcrdma_bc_post_recv(struct rpcrdma_xprt *, unsigned int);
void xprt_rdma_bc_free_rqst(struct rpc_rqst *);
void xprt_rdma_bc_destroy(struct rpc_xprt *, unsigned int);
#endif /* CONFIG_SUNRPC_BACKCHANNEL */
/* Temporary NFS request map cache. Created in svc_rdma.c */
extern struct kmem_cache *svc_rdma_map_cachep;
/* WR context cache. Created in svc_rdma.c */