[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: Greg Banks <gnb@melbourne.sgi.com>
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 5eabded..c27d806 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -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 @@
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 @@
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 */
diff --git a/include/linux/sunrpc/svcsock.h b/include/linux/sunrpc/svcsock.h
index 7154e71..4c29615 100644
--- a/include/linux/sunrpc/svcsock.h
+++ b/include/linux/sunrpc/svcsock.h
@@ -20,6 +20,7 @@
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;
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 0c2c522..6750cd4 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -32,6 +32,7 @@
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 @@
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 @@
}
/*
- * 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 @@
/* Unregister service with the portmapper */
svc_register(serv, 0, 0);
+ kfree(serv->sv_pools);
kfree(serv);
}
@@ -158,10 +180,11 @@
}
/*
- * 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 @@
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 @@
}
/*
- * 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 */
diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
index a38df45..b78659a 100644
--- a/net/sunrpc/svcsock.c
+++ b/net/sunrpc/svcsock.c
@@ -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 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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
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 @@
/*
* 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;
+ unsigned int i;
+ struct svc_pool *pool;
- 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);
+ 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 @@
/* 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 @@
/* 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 @@
}
/*
- * 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 @@
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 @@
*/
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 @@
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--;
