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Subject: [PATCH 12/14] SUNRPC: discard SP_CONGESTED
From:   NeilBrown <neilb@suse.de>
To:     Chuck Lever <chuck.lever@oracle.com>,
        Jeff Layton <jlayton@kernel.org>
Cc:     linux-nfs@vger.kernel.org
Date:   Tue, 18 Jul 2023 16:38:08 +1000
Message-ID: <168966228867.11075.5024166935997611658.stgit@noble.brown>
In-Reply-To: <168966227838.11075.2974227708495338626.stgit@noble.brown>
References: <168966227838.11075.2974227708495338626.stgit@noble.brown>
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We can tell if a pool is congested by checking if the idle list is
empty.  We don't need a separate flag.

Signed-off-by: NeilBrown <neilb@suse.de>
---
 include/linux/sunrpc/svc.h    |    1 -
 include/trace/events/sunrpc.h |    1 -
 net/sunrpc/svc.c              |    1 -
 net/sunrpc/svc_xprt.c         |    4 +---
 4 files changed, 1 insertion(+), 6 deletions(-)

diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index ec8088d5b57f..f5b69e6da0f8 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -51,7 +51,6 @@ struct svc_pool {
 /* bits for sp_flags */
 enum {
 	SP_TASK_PENDING,	/* still work to do even if no xprt is queued */
-	SP_CONGESTED,		/* all threads are busy, none idle */
 	SP_NEED_VICTIM,		/* One thread needs to agree to exit */
 	SP_VICTIM_REMAINS,	/* One thread needs to actually exit */
 };
diff --git a/include/trace/events/sunrpc.h b/include/trace/events/sunrpc.h
index dd0323c40ef5..470c5ba07fba 100644
--- a/include/trace/events/sunrpc.h
+++ b/include/trace/events/sunrpc.h
@@ -2040,7 +2040,6 @@ TRACE_EVENT(svc_xprt_enqueue,
 #define show_svc_pool_flags(x)						\
 	__print_flags(x, "|",						\
 		{ BIT(SP_TASK_PENDING),		"TASK_PENDING" },	\
-		{ BIT(SP_CONGESTED),		"CONGESTED" },		\
 		{ BIT(SP_NEED_VICTIM),		"NEED_VICTIM" },	\
 		{ BIT(SP_VICTIM_REMAINS),	"VICTIM_REMAINS" })
 DECLARE_EVENT_CLASS(svc_pool_scheduler_class,
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 028de8f662a8..f6da390932cd 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -721,7 +721,6 @@ void svc_pool_wake_idle_thread(struct svc_serv *serv,
 
 	trace_svc_pool_starved(serv, pool);
 	percpu_counter_inc(&pool->sp_threads_starved);
-	set_bit(SP_CONGESTED, &pool->sp_flags);
 }
 EXPORT_SYMBOL_GPL(svc_pool_wake_idle_thread);
 
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index 1d134415ae3f..b82a66f68f17 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -734,8 +734,6 @@ static void svc_wait_for_work(struct svc_rqst *rqstp)
 	struct svc_pool		*pool = rqstp->rq_pool;
 
 	set_current_state(TASK_IDLE);
-	smp_mb__before_atomic();
-	clear_bit(SP_CONGESTED, &pool->sp_flags);
 	spin_lock_bh(&pool->sp_lock);
 	list_add(&rqstp->rq_idle, &pool->sp_idle_threads);
 	spin_unlock_bh(&pool->sp_lock);
@@ -787,7 +785,7 @@ static void svc_wait_for_work(struct svc_rqst *rqstp)
 	/* Normally we will wait up to 5 seconds for any required
 	 * cache information to be provided.
 	 */
-	if (!test_bit(SP_CONGESTED, &pool->sp_flags))
+	if (!list_empty(&pool->sp_idle_threads))
 		rqstp->rq_chandle.thread_wait = 5*HZ;
 	else
 		rqstp->rq_chandle.thread_wait = 1*HZ;