Commit 3262c816 authored by Greg Banks's avatar Greg Banks Committed by Linus Torvalds
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[PATCH] knfsd: split svc_serv into pools



Split out the list of idle threads and pending sockets from svc_serv into a
new svc_pool structure, and allocate a fixed number (in this patch, 1) of
pools per svc_serv.  The new structure contains a lock which takes over
several of the duties of svc_serv->sv_lock, which is now relegated to
protecting only sv_tempsocks, sv_permsocks, and sv_tmpcnt in svc_serv.

The point is to move the hottest fields out of svc_serv and into svc_pool,
allowing a following patch to arrange for a svc_pool per NUMA node or per CPU.
 This is a major step towards making the NFS server NUMA-friendly.
Signed-off-by: default avatarGreg Banks <gnb@melbourne.sgi.com>
Signed-off-by: default avatarNeil Brown <neilb@suse.de>
Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent c081a0c7
......@@ -17,6 +17,25 @@
#include <linux/wait.h>
#include <linux/mm.h>
/*
*
* RPC service thread pool.
*
* Pool of threads and temporary sockets. Generally there is only
* a single one of these per RPC service, but on NUMA machines those
* services that can benefit from it (i.e. nfs but not lockd) will
* have one pool per NUMA node. This optimisation reduces cross-
* node traffic on multi-node NUMA NFS servers.
*/
struct svc_pool {
unsigned int sp_id; /* pool id; also node id on NUMA */
spinlock_t sp_lock; /* protects all fields */
struct list_head sp_threads; /* idle server threads */
struct list_head sp_sockets; /* pending sockets */
unsigned int sp_nrthreads; /* # of threads in pool */
} ____cacheline_aligned_in_smp;
/*
* RPC service.
*
......@@ -28,8 +47,6 @@
* We currently do not support more than one RPC program per daemon.
*/
struct svc_serv {
struct list_head sv_threads; /* idle server threads */
struct list_head sv_sockets; /* pending sockets */
struct svc_program * sv_program; /* RPC program */
struct svc_stat * sv_stats; /* RPC statistics */
spinlock_t sv_lock;
......@@ -44,6 +61,9 @@ struct svc_serv {
char * sv_name; /* service name */
unsigned int sv_nrpools; /* number of thread pools */
struct svc_pool * sv_pools; /* array of thread pools */
void (*sv_shutdown)(struct svc_serv *serv);
/* Callback to use when last thread
* exits.
......@@ -138,6 +158,7 @@ struct svc_rqst {
int rq_addrlen;
struct svc_serv * rq_server; /* RPC service definition */
struct svc_pool * rq_pool; /* thread pool */
struct svc_procedure * rq_procinfo; /* procedure info */
struct auth_ops * rq_authop; /* authentication flavour */
struct svc_cred rq_cred; /* auth info */
......
......@@ -20,6 +20,7 @@ struct svc_sock {
struct socket * sk_sock; /* berkeley socket layer */
struct sock * sk_sk; /* INET layer */
struct svc_pool * sk_pool; /* current pool iff queued */
struct svc_serv * sk_server; /* service for this socket */
atomic_t sk_inuse; /* use count */
unsigned long sk_flags;
......
......@@ -32,6 +32,7 @@ svc_create(struct svc_program *prog, unsigned int bufsize,
struct svc_serv *serv;
int vers;
unsigned int xdrsize;
unsigned int i;
if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
return NULL;
......@@ -55,13 +56,33 @@ svc_create(struct svc_program *prog, unsigned int bufsize,
prog = prog->pg_next;
}
serv->sv_xdrsize = xdrsize;
INIT_LIST_HEAD(&serv->sv_threads);
INIT_LIST_HEAD(&serv->sv_sockets);
INIT_LIST_HEAD(&serv->sv_tempsocks);
INIT_LIST_HEAD(&serv->sv_permsocks);
init_timer(&serv->sv_temptimer);
spin_lock_init(&serv->sv_lock);
serv->sv_nrpools = 1;
serv->sv_pools =
kcalloc(sizeof(struct svc_pool), serv->sv_nrpools,
GFP_KERNEL);
if (!serv->sv_pools) {
kfree(serv);
return NULL;
}
for (i = 0; i < serv->sv_nrpools; i++) {
struct svc_pool *pool = &serv->sv_pools[i];
dprintk("initialising pool %u for %s\n",
i, serv->sv_name);
pool->sp_id = i;
INIT_LIST_HEAD(&pool->sp_threads);
INIT_LIST_HEAD(&pool->sp_sockets);
spin_lock_init(&pool->sp_lock);
}
/* Remove any stale portmap registrations */
svc_register(serv, 0, 0);
......@@ -69,7 +90,7 @@ svc_create(struct svc_program *prog, unsigned int bufsize,
}
/*
* Destroy an RPC service
* Destroy an RPC service. Should be called with the BKL held
*/
void
svc_destroy(struct svc_serv *serv)
......@@ -110,6 +131,7 @@ svc_destroy(struct svc_serv *serv)
/* Unregister service with the portmapper */
svc_register(serv, 0, 0);
kfree(serv->sv_pools);
kfree(serv);
}
......@@ -158,10 +180,11 @@ svc_release_buffer(struct svc_rqst *rqstp)
}
/*
* Create a server thread
* Create a thread in the given pool. Caller must hold BKL.
*/
int
svc_create_thread(svc_thread_fn func, struct svc_serv *serv)
static int
__svc_create_thread(svc_thread_fn func, struct svc_serv *serv,
struct svc_pool *pool)
{
struct svc_rqst *rqstp;
int error = -ENOMEM;
......@@ -178,7 +201,11 @@ svc_create_thread(svc_thread_fn func, struct svc_serv *serv)
goto out_thread;
serv->sv_nrthreads++;
spin_lock_bh(&pool->sp_lock);
pool->sp_nrthreads++;
spin_unlock_bh(&pool->sp_lock);
rqstp->rq_server = serv;
rqstp->rq_pool = pool;
error = kernel_thread((int (*)(void *)) func, rqstp, 0);
if (error < 0)
goto out_thread;
......@@ -193,17 +220,32 @@ out_thread:
}
/*
* Destroy an RPC server thread
* Create a thread in the default pool. Caller must hold BKL.
*/
int
svc_create_thread(svc_thread_fn func, struct svc_serv *serv)
{
return __svc_create_thread(func, serv, &serv->sv_pools[0]);
}
/*
* Called from a server thread as it's exiting. Caller must hold BKL.
*/
void
svc_exit_thread(struct svc_rqst *rqstp)
{
struct svc_serv *serv = rqstp->rq_server;
struct svc_pool *pool = rqstp->rq_pool;
svc_release_buffer(rqstp);
kfree(rqstp->rq_resp);
kfree(rqstp->rq_argp);
kfree(rqstp->rq_auth_data);
spin_lock_bh(&pool->sp_lock);
pool->sp_nrthreads--;
spin_unlock_bh(&pool->sp_lock);
kfree(rqstp);
/* Release the server */
......
......@@ -46,7 +46,10 @@
/* SMP locking strategy:
*
* svc_serv->sv_lock protects most stuff for that service.
* svc_pool->sp_lock protects most of the fields of that pool.
* svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
* when both need to be taken (rare), svc_serv->sv_lock is first.
* BKL protects svc_serv->sv_nrthread.
* svc_sock->sk_defer_lock protects the svc_sock->sk_deferred list
* svc_sock->sk_flags.SK_BUSY prevents a svc_sock being enqueued multiply.
*
......@@ -82,22 +85,22 @@ static struct cache_deferred_req *svc_defer(struct cache_req *req);
static int svc_conn_age_period = 6*60;
/*
* Queue up an idle server thread. Must have serv->sv_lock held.
* Queue up an idle server thread. Must have pool->sp_lock held.
* Note: this is really a stack rather than a queue, so that we only
* use as many different threads as we need, and the rest don't polute
* use as many different threads as we need, and the rest don't pollute
* the cache.
*/
static inline void
svc_serv_enqueue(struct svc_serv *serv, struct svc_rqst *rqstp)
svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp)
{
list_add(&rqstp->rq_list, &serv->sv_threads);
list_add(&rqstp->rq_list, &pool->sp_threads);
}
/*
* Dequeue an nfsd thread. Must have serv->sv_lock held.
* Dequeue an nfsd thread. Must have pool->sp_lock held.
*/
static inline void
svc_serv_dequeue(struct svc_serv *serv, struct svc_rqst *rqstp)
svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
{
list_del(&rqstp->rq_list);
}
......@@ -148,6 +151,7 @@ static void
svc_sock_enqueue(struct svc_sock *svsk)
{
struct svc_serv *serv = svsk->sk_server;
struct svc_pool *pool = &serv->sv_pools[0];
struct svc_rqst *rqstp;
if (!(svsk->sk_flags &
......@@ -156,10 +160,10 @@ svc_sock_enqueue(struct svc_sock *svsk)
if (test_bit(SK_DEAD, &svsk->sk_flags))
return;
spin_lock_bh(&serv->sv_lock);
spin_lock_bh(&pool->sp_lock);
if (!list_empty(&serv->sv_threads) &&
!list_empty(&serv->sv_sockets))
if (!list_empty(&pool->sp_threads) &&
!list_empty(&pool->sp_sockets))
printk(KERN_ERR
"svc_sock_enqueue: threads and sockets both waiting??\n");
......@@ -179,6 +183,8 @@ svc_sock_enqueue(struct svc_sock *svsk)
dprintk("svc: socket %p busy, not enqueued\n", svsk->sk_sk);
goto out_unlock;
}
BUG_ON(svsk->sk_pool != NULL);
svsk->sk_pool = pool;
set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
if (((atomic_read(&svsk->sk_reserved) + serv->sv_bufsz)*2
......@@ -189,19 +195,20 @@ svc_sock_enqueue(struct svc_sock *svsk)
dprintk("svc: socket %p no space, %d*2 > %ld, not enqueued\n",
svsk->sk_sk, atomic_read(&svsk->sk_reserved)+serv->sv_bufsz,
svc_sock_wspace(svsk));
svsk->sk_pool = NULL;
clear_bit(SK_BUSY, &svsk->sk_flags);
goto out_unlock;
}
clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
if (!list_empty(&serv->sv_threads)) {
rqstp = list_entry(serv->sv_threads.next,
if (!list_empty(&pool->sp_threads)) {
rqstp = list_entry(pool->sp_threads.next,
struct svc_rqst,
rq_list);
dprintk("svc: socket %p served by daemon %p\n",
svsk->sk_sk, rqstp);
svc_serv_dequeue(serv, rqstp);
svc_thread_dequeue(pool, rqstp);
if (rqstp->rq_sock)
printk(KERN_ERR
"svc_sock_enqueue: server %p, rq_sock=%p!\n",
......@@ -210,28 +217,30 @@ svc_sock_enqueue(struct svc_sock *svsk)
atomic_inc(&svsk->sk_inuse);
rqstp->rq_reserved = serv->sv_bufsz;
atomic_add(rqstp->rq_reserved, &svsk->sk_reserved);
BUG_ON(svsk->sk_pool != pool);
wake_up(&rqstp->rq_wait);
} else {
dprintk("svc: socket %p put into queue\n", svsk->sk_sk);
list_add_tail(&svsk->sk_ready, &serv->sv_sockets);
list_add_tail(&svsk->sk_ready, &pool->sp_sockets);
BUG_ON(svsk->sk_pool != pool);
}
out_unlock:
spin_unlock_bh(&serv->sv_lock);
spin_unlock_bh(&pool->sp_lock);
}
/*
* Dequeue the first socket. Must be called with the serv->sv_lock held.
* Dequeue the first socket. Must be called with the pool->sp_lock held.
*/
static inline struct svc_sock *
svc_sock_dequeue(struct svc_serv *serv)
svc_sock_dequeue(struct svc_pool *pool)
{
struct svc_sock *svsk;
if (list_empty(&serv->sv_sockets))
if (list_empty(&pool->sp_sockets))
return NULL;
svsk = list_entry(serv->sv_sockets.next,
svsk = list_entry(pool->sp_sockets.next,
struct svc_sock, sk_ready);
list_del_init(&svsk->sk_ready);
......@@ -250,6 +259,7 @@ svc_sock_dequeue(struct svc_serv *serv)
static inline void
svc_sock_received(struct svc_sock *svsk)
{
svsk->sk_pool = NULL;
clear_bit(SK_BUSY, &svsk->sk_flags);
svc_sock_enqueue(svsk);
}
......@@ -322,25 +332,33 @@ svc_sock_release(struct svc_rqst *rqstp)
/*
* External function to wake up a server waiting for data
* This really only makes sense for services like lockd
* which have exactly one thread anyway.
*/
void
svc_wake_up(struct svc_serv *serv)
{
struct svc_rqst *rqstp;
spin_lock_bh(&serv->sv_lock);
if (!list_empty(&serv->sv_threads)) {
rqstp = list_entry(serv->sv_threads.next,
struct svc_rqst,
rq_list);
dprintk("svc: daemon %p woken up.\n", rqstp);
/*
svc_serv_dequeue(serv, rqstp);
rqstp->rq_sock = NULL;
*/
wake_up(&rqstp->rq_wait);
unsigned int i;
struct svc_pool *pool;
for (i = 0; i < serv->sv_nrpools; i++) {
pool = &serv->sv_pools[i];
spin_lock_bh(&pool->sp_lock);
if (!list_empty(&pool->sp_threads)) {
rqstp = list_entry(pool->sp_threads.next,
struct svc_rqst,
rq_list);
dprintk("svc: daemon %p woken up.\n", rqstp);
/*
svc_thread_dequeue(pool, rqstp);
rqstp->rq_sock = NULL;
*/
wake_up(&rqstp->rq_wait);
}
spin_unlock_bh(&pool->sp_lock);
}
spin_unlock_bh(&serv->sv_lock);
}
/*
......@@ -603,7 +621,10 @@ svc_udp_recvfrom(struct svc_rqst *rqstp)
/* udp sockets need large rcvbuf as all pending
* requests are still in that buffer. sndbuf must
* also be large enough that there is enough space
* for one reply per thread.
* for one reply per thread. We count all threads
* rather than threads in a particular pool, which
* provides an upper bound on the number of threads
* which will access the socket.
*/
svc_sock_setbufsize(svsk->sk_sock,
(serv->sv_nrthreads+3) * serv->sv_bufsz,
......@@ -948,6 +969,11 @@ svc_tcp_recvfrom(struct svc_rqst *rqstp)
/* sndbuf needs to have room for one request
* per thread, otherwise we can stall even when the
* network isn't a bottleneck.
*
* We count all threads rather than threads in a
* particular pool, which provides an upper bound
* on the number of threads which will access the socket.
*
* rcvbuf just needs to be able to hold a few requests.
* Normally they will be removed from the queue
* as soon a a complete request arrives.
......@@ -1163,13 +1189,16 @@ svc_sock_update_bufs(struct svc_serv *serv)
}
/*
* Receive the next request on any socket.
* Receive the next request on any socket. This code is carefully
* organised not to touch any cachelines in the shared svc_serv
* structure, only cachelines in the local svc_pool.
*/
int
svc_recv(struct svc_rqst *rqstp, long timeout)
{
struct svc_sock *svsk =NULL;
struct svc_serv *serv = rqstp->rq_server;
struct svc_pool *pool = rqstp->rq_pool;
int len;
int pages;
struct xdr_buf *arg;
......@@ -1219,15 +1248,15 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
if (signalled())
return -EINTR;
spin_lock_bh(&serv->sv_lock);
if ((svsk = svc_sock_dequeue(serv)) != NULL) {
spin_lock_bh(&pool->sp_lock);
if ((svsk = svc_sock_dequeue(pool)) != NULL) {
rqstp->rq_sock = svsk;
atomic_inc(&svsk->sk_inuse);
rqstp->rq_reserved = serv->sv_bufsz;
atomic_add(rqstp->rq_reserved, &svsk->sk_reserved);
} else {
/* No data pending. Go to sleep */
svc_serv_enqueue(serv, rqstp);
svc_thread_enqueue(pool, rqstp);
/*
* We have to be able to interrupt this wait
......@@ -1235,26 +1264,26 @@ svc_recv(struct svc_rqst *rqstp, long timeout)
*/
set_current_state(TASK_INTERRUPTIBLE);
add_wait_queue(&rqstp->rq_wait, &wait);
spin_unlock_bh(&serv->sv_lock);
spin_unlock_bh(&pool->sp_lock);
schedule_timeout(timeout);
try_to_freeze();
spin_lock_bh(&serv->sv_lock);
spin_lock_bh(&pool->sp_lock);
remove_wait_queue(&rqstp->rq_wait, &wait);
if (!(svsk = rqstp->rq_sock)) {
svc_serv_dequeue(serv, rqstp);
spin_unlock_bh(&serv->sv_lock);
svc_thread_dequeue(pool, rqstp);
spin_unlock_bh(&pool->sp_lock);
dprintk("svc: server %p, no data yet\n", rqstp);
return signalled()? -EINTR : -EAGAIN;
}
}
spin_unlock_bh(&serv->sv_lock);
spin_unlock_bh(&pool->sp_lock);
dprintk("svc: server %p, socket %p, inuse=%d\n",
rqstp, svsk, atomic_read(&svsk->sk_inuse));
dprintk("svc: server %p, pool %u, socket %p, inuse=%d\n",
rqstp, pool->sp_id, svsk, atomic_read(&svsk->sk_inuse));
len = svsk->sk_recvfrom(rqstp);
dprintk("svc: got len=%d\n", len);
......@@ -1553,7 +1582,13 @@ svc_delete_socket(struct svc_sock *svsk)
if (!test_and_set_bit(SK_DETACHED, &svsk->sk_flags))
list_del_init(&svsk->sk_list);
list_del_init(&svsk->sk_ready);
/*
* We used to delete the svc_sock from whichever list
* it's sk_ready node was on, but we don't actually
* need to. This is because the only time we're called
* while still attached to a queue, the queue itself
* is about to be destroyed (in svc_destroy).
*/
if (!test_and_set_bit(SK_DEAD, &svsk->sk_flags))
if (test_bit(SK_TEMP, &svsk->sk_flags))
serv->sv_tmpcnt--;
......
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