From: Chuck Lever <chuck.lever@xxxxxxxxxx>
Refactor: Extract the loop that finds an idle service thread from
svc_xprt_enqueue() and svc_wake_up(). Both functions do just about
the same thing.
Signed-off-by: Chuck Lever <chuck.lever@xxxxxxxxxx>
---
include/linux/sunrpc/svc.h | 1 +
net/sunrpc/svc.c | 28 ++++++++++++++++++++++++++
net/sunrpc/svc_xprt.c | 48 +++++++++++++++-----------------------------
3 files changed, 45 insertions(+), 32 deletions(-)
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index f8751118c122..dc2d90a655e2 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -427,6 +427,7 @@ int svc_register(const struct svc_serv *, struct net *, const int,
void svc_wake_up(struct svc_serv *);
void svc_reserve(struct svc_rqst *rqstp, int space);
+struct svc_rqst *svc_pool_wake_idle_thread(struct svc_pool *pool);
struct svc_pool *svc_pool_for_cpu(struct svc_serv *serv);
char * svc_print_addr(struct svc_rqst *, char *, size_t);
const char * svc_proc_name(const struct svc_rqst *rqstp);
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 587811a002c9..05ee92b5fa1e 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -689,6 +689,34 @@ svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
return rqstp;
}
+/**
+ * svc_pool_wake_idle_thread - Awaken an idle thread in @pool
+ * @pool: service thread pool
+ *
+ * Returns an idle service thread (now marked BUSY), or NULL
+ * if no service threads are available. Finding an idle service
+ * thread and marking it BUSY is atomic with respect to other
+ * calls to svc_pool_wake_idle_thread().
+ */
+struct svc_rqst *svc_pool_wake_idle_thread(struct svc_pool *pool)
+{
+ struct svc_rqst *rqstp;
+
+ rcu_read_lock();
+ list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
+ if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
+ continue;
+
+ rcu_read_unlock();
+ WRITE_ONCE(rqstp->rq_qtime, ktime_get());
+ wake_up_process(rqstp->rq_task);
+ percpu_counter_inc(&pool->sp_threads_woken);
+ return rqstp;
+ }
+ rcu_read_unlock();
+ return NULL;
+}
+
/*
* Choose a pool in which to create a new thread, for svc_set_num_threads
*/
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 62c7919ea610..89302bf09b77 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -455,8 +455,8 @@ static bool svc_xprt_ready(struct svc_xprt *xprt)
*/
void svc_xprt_enqueue(struct svc_xprt *xprt)
{
+ struct svc_rqst *rqstp;
struct svc_pool *pool;
- struct svc_rqst *rqstp = NULL;
if (!svc_xprt_ready(xprt))
return;
@@ -476,20 +476,10 @@ void svc_xprt_enqueue(struct svc_xprt *xprt)
list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
spin_unlock_bh(&pool->sp_lock);
- /* find a thread for this xprt */
- rcu_read_lock();
- list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
- if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
- continue;
- percpu_counter_inc(&pool->sp_threads_woken);
- rqstp->rq_qtime = ktime_get();
- wake_up_process(rqstp->rq_task);
- goto out_unlock;
- }
- set_bit(SP_CONGESTED, &pool->sp_flags);
- rqstp = NULL;
-out_unlock:
- rcu_read_unlock();
+ rqstp = svc_pool_wake_idle_thread(pool);
+ if (!rqstp)
+ set_bit(SP_CONGESTED, &pool->sp_flags);
+
trace_svc_xprt_enqueue(xprt, rqstp);
}
EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
@@ -581,7 +571,10 @@ static void svc_xprt_release(struct svc_rqst *rqstp)
svc_xprt_put(xprt);
}
-/*
+/**
+ * svc_wake_up - Wake up a service thread for non-transport work
+ * @serv: RPC service
+ *
* Some svc_serv's will have occasional work to do, even when a xprt is not
* waiting to be serviced. This function is there to "kick" a task in one of
* those services so that it can wake up and do that work. Note that we only
@@ -590,27 +583,18 @@ static void svc_xprt_release(struct svc_rqst *rqstp)
*/
void svc_wake_up(struct svc_serv *serv)
{
+ struct svc_pool *pool = &serv->sv_pools[0];
struct svc_rqst *rqstp;
- struct svc_pool *pool;
- pool = &serv->sv_pools[0];
-
- rcu_read_lock();
- list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
- /* skip any that aren't queued */
- if (test_bit(RQ_BUSY, &rqstp->rq_flags))
- continue;
- rcu_read_unlock();
- wake_up_process(rqstp->rq_task);
- trace_svc_wake_up(rqstp->rq_task->pid);
+ rqstp = svc_pool_wake_idle_thread(pool);
+ if (!rqstp) {
+ set_bit(SP_TASK_PENDING, &pool->sp_flags);
+ smp_wmb();
+ trace_svc_wake_up(0);
return;
}
- rcu_read_unlock();
- /* No free entries available */
- set_bit(SP_TASK_PENDING, &pool->sp_flags);
- smp_wmb();
- trace_svc_wake_up(0);
+ trace_svc_wake_up(rqstp->rq_task->pid);
}
EXPORT_SYMBOL_GPL(svc_wake_up);
