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From: Junchang Wang <junchangwang@gmail.com>
To: paulmck@linux.ibm.com, akiyks@gmail.com
Cc: perfbook@vger.kernel.org, Junchang Wang <junchangwang@gmail.com>
Subject: [PATCH v2 1/3] rcu: Use READ_ONCE() and WRITE_ONCE() for shared variable rcu_gp_ctr
Date: Thu, 25 Apr 2019 16:29:52 +0800	[thread overview]
Message-ID: <1556180994-16131-2-git-send-email-junchangwang@gmail.com> (raw)
In-Reply-To: <1556180994-16131-1-git-send-email-junchangwang@gmail.com>

Signed-off-by: Junchang Wang <junchangwang@gmail.com>
Reviewed-by: Akira Yokosawa <akiyks@gmail.com>
---
 CodeSamples/defer/rcu.c | 2 +-
 CodeSamples/defer/rcu.h | 4 ++--
 2 files changed, 3 insertions(+), 3 deletions(-)

diff --git a/CodeSamples/defer/rcu.c b/CodeSamples/defer/rcu.c
index 4b868cc..66792e5 100644
--- a/CodeSamples/defer/rcu.c
+++ b/CodeSamples/defer/rcu.c
@@ -35,7 +35,7 @@ void synchronize_rcu(void)
 
 	/* Advance to a new grace-period number, enforce ordering. */
 
-	rcu_gp_ctr += 2;
+	WRITE_ONCE(rcu_gp_ctr, rcu_gp_ctr + 2);
 	smp_mb();
 
 	/*
diff --git a/CodeSamples/defer/rcu.h b/CodeSamples/defer/rcu.h
index f493f8b..b49ab14 100644
--- a/CodeSamples/defer/rcu.h
+++ b/CodeSamples/defer/rcu.h
@@ -41,7 +41,7 @@ static inline void rcu_read_lock(void)
 	 * periodic per-thread processing.)
 	 */
 
-	__get_thread_var(rcu_reader_gp) = rcu_gp_ctr + 1;
+	__get_thread_var(rcu_reader_gp) = READ_ONCE(rcu_gp_ctr) + 1;
 	smp_mb();
 }
 
@@ -55,7 +55,7 @@ static inline void rcu_read_unlock(void)
 	 */
 
 	smp_mb();
-	__get_thread_var(rcu_reader_gp) = rcu_gp_ctr;
+	__get_thread_var(rcu_reader_gp) = READ_ONCE(rcu_gp_ctr);
 }
 
 extern void synchronize_rcu(void);
-- 
2.7.4


  reply	other threads:[~2019-04-25  8:29 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-04-25  8:29 [PATCH v2 0/3] Toyrcu: replace plain accesses with READ_ONCE() and Junchang Wang
2019-04-25  8:29 ` Junchang Wang [this message]
2019-04-25  8:29 ` [PATCH v2 2/3] rcu_nest: Use READ_ONCE() and WRITE_ONCE() for shared variable rcu_gp_ctr Junchang Wang
2019-04-25  8:29 ` [PATCH v2 3/3] rcu_qs: Use READ_ONCE() AND " Junchang Wang
2019-04-25 15:38 ` [PATCH v2 0/3] Toyrcu: replace plain accesses with READ_ONCE() and Akira Yokosawa
2019-04-26  8:15   ` Junchang Wang
2019-04-26 13:43   ` Paul E. McKenney
2019-04-27 14:27     ` Akira Yokosawa
2019-04-28 14:57       ` Junchang Wang

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