Commit d2f0ef1c authored by Chuck Lever's avatar Chuck Lever
Browse files

SUNRPC: Clean up svc_set_num_threads 



Document the API contract and remove stale or obvious comments.

Reviewed-by: default avatarJeff Layton <jlayton@redhat.com>
Reviewed-by: default avatarNeilBrown <neilb@suse.de>
Signed-off-by: default avatarChuck Lever <chuck.lever@oracle.com>
parent f208e950

net/sunrpc/svc.c

+25 −35
Original line number Diff line number Diff line
@@ -723,23 +723,14 @@ bool svc_pool_wake_idle_thread(struct svc_pool *pool) 
	return false;

}



/*

 * Choose a pool in which to create a new thread, for svc_set_num_threads

 */

static inline struct svc_pool *

choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)

static struct svc_pool *

svc_pool_next(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)

{

	if (pool != NULL)

		return pool;



	return &serv->sv_pools[(*state)++ % serv->sv_nrpools];

	return pool ? pool : &serv->sv_pools[(*state)++ % serv->sv_nrpools];

}



/*

 * Choose a thread to kill, for svc_set_num_threads

 */

static inline struct task_struct *

choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)

static struct task_struct *

svc_pool_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)

{

	unsigned int i;

	struct task_struct *task = NULL;
@@ -747,7 +738,6 @@ choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state) 
	if (pool != NULL) {

		spin_lock_bh(&pool->sp_lock);

	} else {

		/* choose a pool in round-robin fashion */

		for (i = 0; i < serv->sv_nrpools; i++) {

			pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];

			spin_lock_bh(&pool->sp_lock);
@@ -762,21 +752,15 @@ choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state) 
	if (!list_empty(&pool->sp_all_threads)) {

		struct svc_rqst *rqstp;



		/*

		 * Remove from the pool->sp_all_threads list

		 * so we don't try to kill it again.

		 */

		rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);

		set_bit(RQ_VICTIM, &rqstp->rq_flags);

		list_del_rcu(&rqstp->rq_all);

		task = rqstp->rq_task;

	}

	spin_unlock_bh(&pool->sp_lock);



	return task;

}



/* create new threads */

static int

svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)

{
@@ -788,13 +772,12 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs) 


	do {

		nrservs--;

		chosen_pool = choose_pool(serv, pool, &state);



		chosen_pool = svc_pool_next(serv, pool, &state);

		node = svc_pool_map_get_node(chosen_pool->sp_id);



		rqstp = svc_prepare_thread(serv, chosen_pool, node);

		if (IS_ERR(rqstp))

			return PTR_ERR(rqstp);



		task = kthread_create_on_node(serv->sv_threadfn, rqstp,

					      node, "%s", serv->sv_name);

		if (IS_ERR(task)) {
@@ -813,15 +796,6 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs) 
	return 0;

}



/*

 * Create or destroy enough new threads to make the number

 * of threads the given number.  If `pool' is non-NULL, applies

 * only to threads in that pool, otherwise round-robins between

 * all pools.  Caller must ensure that mutual exclusion between this and

 * server startup or shutdown.

 */



/* destroy old threads */

static int

svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)

{
@@ -829,9 +803,8 @@ svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs) 
	struct task_struct *task;

	unsigned int state = serv->sv_nrthreads-1;



	/* destroy old threads */

	do {

		task = choose_victim(serv, pool, &state);

		task = svc_pool_victim(serv, pool, &state);

		if (task == NULL)

			break;

		rqstp = kthread_data(task);
@@ -843,6 +816,23 @@ svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs) 
	return 0;

}



/**

 * svc_set_num_threads - adjust number of threads per RPC service

 * @serv: RPC service to adjust

 * @pool: Specific pool from which to choose threads, or NULL

 * @nrservs: New number of threads for @serv (0 or less means kill all threads)

 *

 * Create or destroy threads to make the number of threads for @serv the

 * given number. If @pool is non-NULL, change only threads in that pool;

 * otherwise, round-robin between all pools for @serv. @serv's

 * sv_nrthreads is adjusted for each thread created or destroyed.

 *

 * Caller must ensure mutual exclusion between this and server startup or

 * shutdown.

 *

 * Returns zero on success or a negative errno if an error occurred while

 * starting a thread.

 */

int

svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)

{