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[PATCH] knfsd: split svc_serv into pools

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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>
This commit is contained in:
Greg Banks
2006-10-02 02:17:58 -07:00
committed by Linus Torvalds
parent c081a0c7cf
commit 3262c816a3
4 changed files with 152 additions and 53 deletions
Download Patch File Download Diff File Expand all files Collapse all files

123
net/sunrpc/svcsock.c
View File

@@ -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;
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 @@ 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--;