0121-locking-rwsem-spin-faster.patch

From 0000000000000000000000000000000000000000 Mon Sep 17 00:00:00 2001
From: Arjan van de Ven <arjan@linux.intel.com>
Date: Sun, 18 Feb 2018 23:35:41 +0000
Subject: [PATCH] locking: rwsem: spin faster

tweak rwsem owner spinning a bit
---
 kernel/locking/rwsem.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/kernel/locking/rwsem.c b/kernel/locking/rwsem.c
index abba5df50006..b9fab2d55b93 100644
--- a/kernel/locking/rwsem.c
+++ b/kernel/locking/rwsem.c
@@ -668,6 +668,7 @@ rwsem_spin_on_owner(struct rw_semaphore *sem)
 	struct task_struct *new, *owner;
 	unsigned long flags, new_flags;
 	enum owner_state state;
+	int i = 0;
 
 	owner = rwsem_owner_flags(sem, &flags);
 	state = rwsem_owner_state(owner, flags);
@@ -701,7 +702,8 @@ rwsem_spin_on_owner(struct rw_semaphore *sem)
 			break;
 		}
 
-		cpu_relax();
+		if (i++ > 1000)
+			cpu_relax();
 	}
 	rcu_read_unlock();
 
-- 
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