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From: Lai Jiangshan <laijs@cn.fujitsu.com>
To: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Lai Jiangshan <laijs@cn.fujitsu.com>,
	linux-kernel@vger.kernel.org, mingo@elte.hu, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@polymtl.ca,
	josh@joshtriplett.org, niv@us.ibm.com, tglx@linutronix.de,
	peterz@infradead.org, rostedt@goodmis.org,
	Valdis.Kletnieks@vt.edu, dhowells@redhat.com,
	eric.dumazet@gmail.com, darren@dvhart.com, fweisbec@gmail.com,
	patches@linaro.org
Subject: [PATCH 3/6] use "int trycount" instead of "bool expedited"
Date: Tue, 6 Mar 2012 17:57:35 +0800	[thread overview]
Message-ID: <1331027858-7648-3-git-send-email-laijs@cn.fujitsu.com> (raw)
In-Reply-To: <1331027858-7648-1-git-send-email-laijs@cn.fujitsu.com>

Signed-off-by: Lai Jiangshan <laijs@cn.fujitsu.com>
---
 kernel/srcu.c |   27 ++++++++++++++-------------
 1 files changed, 14 insertions(+), 13 deletions(-)

diff --git a/kernel/srcu.c b/kernel/srcu.c
index fbe2d5f..d5f3450 100644
--- a/kernel/srcu.c
+++ b/kernel/srcu.c
@@ -254,12 +254,12 @@ EXPORT_SYMBOL_GPL(__srcu_read_unlock);
  * we repeatedly block for 1-millisecond time periods.  This approach
  * has done well in testing, so there is no need for a config parameter.
  */
-#define SYNCHRONIZE_SRCU_READER_DELAY 5
+#define SYNCHRONIZE_SRCU_READER_DELAY	5
+#define SYNCHRONIZE_SRCU_TRYCOUNT	2
+#define SYNCHRONIZE_SRCU_EXP_TRYCOUNT	12
 
-static void wait_idx(struct srcu_struct *sp, int idx, bool expedited)
+static void wait_idx(struct srcu_struct *sp, int idx, int trycount)
 {
-	int trycount = 0;
-
 	/*
 	 * If a reader fetches the index before the ->completed increment,
 	 * but increments its counter after srcu_readers_active_idx_check()
@@ -278,9 +278,10 @@ static void wait_idx(struct srcu_struct *sp, int idx, bool expedited)
 	if (!srcu_readers_active_idx_check(sp, idx)) {
 		udelay(SYNCHRONIZE_SRCU_READER_DELAY);
 		while (!srcu_readers_active_idx_check(sp, idx)) {
-			if (expedited && ++ trycount < 10)
+			if (trycount > 0) {
+				trycount--;
 				udelay(SYNCHRONIZE_SRCU_READER_DELAY);
-			else
+			} else
 				schedule_timeout_interruptible(1);
 		}
 	}
@@ -310,18 +311,18 @@ static void wait_idx(struct srcu_struct *sp, int idx, bool expedited)
  * by the next __synchronize_srcu() invoking wait_idx() for such readers
  * before starting a new grace period.
  */
-static void flip_idx_and_wait(struct srcu_struct *sp, bool expedited)
+static void flip_idx_and_wait(struct srcu_struct *sp, int trycount)
 {
 	int idx;
 
 	idx = sp->completed++ & 0x1;
-	wait_idx(sp, idx, expedited);
+	wait_idx(sp, idx, trycount);
 }
 
 /*
  * Helper function for synchronize_srcu() and synchronize_srcu_expedited().
  */
-static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
+static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
 {
 	rcu_lockdep_assert(!lock_is_held(&sp->dep_map) &&
 			   !lock_is_held(&rcu_bh_lock_map) &&
@@ -357,14 +358,14 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
 	 * fetching ->completed and incrementing their counter, wait_idx()
 	 * will normally not need to wait.
 	 */
-	wait_idx(sp, (sp->completed - 1) & 0x1, expedited);
+	wait_idx(sp, (sp->completed - 1) & 0x1, trycount);
 
 	/*
 	 * Now that wait_idx() has waited for the really old readers,
 	 * invoke flip_idx_and_wait() to flip the counter and wait
 	 * for current SRCU readers.
 	 */
-	flip_idx_and_wait(sp, expedited);
+	flip_idx_and_wait(sp, trycount);
 
 	mutex_unlock(&sp->mutex);
 }
@@ -385,7 +386,7 @@ static void __synchronize_srcu(struct srcu_struct *sp, bool expedited)
  */
 void synchronize_srcu(struct srcu_struct *sp)
 {
-	__synchronize_srcu(sp, 0);
+	__synchronize_srcu(sp, SYNCHRONIZE_SRCU_TRYCOUNT);
 }
 EXPORT_SYMBOL_GPL(synchronize_srcu);
 
@@ -406,7 +407,7 @@ EXPORT_SYMBOL_GPL(synchronize_srcu);
  */
 void synchronize_srcu_expedited(struct srcu_struct *sp)
 {
-	__synchronize_srcu(sp, 1);
+	__synchronize_srcu(sp, SYNCHRONIZE_SRCU_EXP_TRYCOUNT);
 }
 EXPORT_SYMBOL_GPL(synchronize_srcu_expedited);
 
-- 
1.7.4.4


  parent reply	other threads:[~2012-03-06  9:53 UTC|newest]

Thread overview: 100+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2012-02-13  2:09 [PATCH RFC tip/core/rcu] rcu: direct algorithmic SRCU implementation Paul E. McKenney
2012-02-15 12:59 ` Peter Zijlstra
2012-02-16  6:35   ` Paul E. McKenney
2012-02-16 10:50     ` Mathieu Desnoyers
2012-02-16 10:52       ` Peter Zijlstra
2012-02-16 11:14         ` Mathieu Desnoyers
2012-02-15 14:31 ` Mathieu Desnoyers
2012-02-15 14:51   ` Mathieu Desnoyers
2012-02-16  6:38     ` Paul E. McKenney
2012-02-16 11:00       ` Mathieu Desnoyers
2012-02-16 11:51         ` Peter Zijlstra
2012-02-16 12:18           ` Mathieu Desnoyers
2012-02-16 12:44             ` Peter Zijlstra
2012-02-16 14:52               ` Mathieu Desnoyers
2012-02-16 14:58                 ` Peter Zijlstra
2012-02-16 15:13               ` Paul E. McKenney
2012-02-20  7:15 ` Lai Jiangshan
2012-02-20 17:44   ` Paul E. McKenney
2012-02-21  1:11     ` Lai Jiangshan
2012-02-21  1:50       ` Paul E. McKenney
2012-02-21  8:44         ` Lai Jiangshan
2012-02-21 17:24           ` Paul E. McKenney
2012-02-22  9:29             ` [PATCH 1/3 RFC paul/rcu/srcu] srcu: Remove fast check path Lai Jiangshan
2012-02-22  9:29             ` [PATCH 2/3 RFC paul/rcu/srcu] srcu: only increase the upper bit for srcu_read_lock() Lai Jiangshan
2012-02-22  9:50               ` Peter Zijlstra
2012-02-22 21:20               ` Paul E. McKenney
2012-02-22 21:26                 ` Paul E. McKenney
2012-02-22 21:39                   ` Steven Rostedt
2012-02-23  1:01                     ` Paul E. McKenney
2012-02-22  9:29             ` [PATCH 3/3 RFC paul/rcu/srcu] srcu: flip only once for every grace period Lai Jiangshan
2012-02-23  1:01               ` Paul E. McKenney
2012-02-24  8:06               ` Lai Jiangshan
2012-02-24 20:01                 ` Paul E. McKenney
2012-02-27  8:01                   ` [PATCH 1/2 RFC] srcu: change the comments of the wait algorithm Lai Jiangshan
2012-02-27  8:01                   ` [PATCH 2/2 RFC] srcu: implement Peter's checking algorithm Lai Jiangshan
2012-02-27 18:30                     ` Paul E. McKenney
2012-02-28  1:51                       ` Lai Jiangshan
2012-02-28 13:47                         ` Paul E. McKenney
2012-02-29 10:07                           ` Lai Jiangshan
2012-02-29 13:55                             ` Paul E. McKenney
2012-03-01  2:31                               ` Lai Jiangshan
2012-03-01 13:20                                 ` Paul E. McKenney
2012-03-10  3:41                                   ` Lai Jiangshan
2012-03-06  8:42             ` [RFC PATCH 0/6 paul/rcu/srcu] srcu: implement call_srcu() Lai Jiangshan
2012-03-06  9:57               ` [PATCH 1/6] remove unused srcu_barrier() Lai Jiangshan
2012-03-06  9:57                 ` [PATCH 2/6] Don't touch the snap in srcu_readers_active() Lai Jiangshan
2012-03-08 19:14                   ` Paul E. McKenney
2012-03-06  9:57                 ` Lai Jiangshan [this message]
2012-03-08 19:25                   ` [PATCH 3/6] use "int trycount" instead of "bool expedited" Paul E. McKenney
2012-03-06  9:57                 ` [PATCH 4/6] remove flip_idx_and_wait() Lai Jiangshan
2012-03-06 10:41                   ` Peter Zijlstra
2012-03-07  3:54                   ` [RFC PATCH 5/5 single-thread-version] implement per-domain single-thread state machine call_srcu() Lai Jiangshan
2012-03-08 13:04                     ` Peter Zijlstra
2012-03-08 14:17                       ` Lai Jiangshan
2012-03-08 13:08                     ` Peter Zijlstra
2012-03-08 20:35                     ` Paul E. McKenney
2012-03-10  3:16                       ` Lai Jiangshan
2012-03-12 18:03                         ` Paul E. McKenney
2012-03-14  7:47                           ` Lai Jiangshan
2012-04-10 20:15                             ` Paul E. McKenney
2012-03-06  9:57                 ` [RFC PATCH 5/6] implement per-cpu&per-domain " Lai Jiangshan
2012-03-06 10:47                   ` Peter Zijlstra
2012-03-08 19:44                     ` Paul E. McKenney
2012-03-06 10:58                   ` Peter Zijlstra
2012-03-06 15:17                     ` Lai Jiangshan
2012-03-06 15:38                       ` Peter Zijlstra
2012-03-08 19:49                         ` Paul E. McKenney
2012-03-10 10:12                           ` Peter Zijlstra
2012-03-12 17:52                             ` Paul E. McKenney
2012-03-06 11:16                   ` Peter Zijlstra
2012-03-06 15:12                     ` Lai Jiangshan
2012-03-06 15:34                       ` Peter Zijlstra
2012-03-08 19:58                         ` Paul E. McKenney
2012-03-10  3:32                           ` Lai Jiangshan
2012-03-10 10:09                           ` Peter Zijlstra
2012-03-12 17:54                             ` Paul E. McKenney
2012-03-12 17:58                               ` Peter Zijlstra
2012-03-12 18:32                                 ` Paul E. McKenney
2012-03-12 20:25                                   ` Peter Zijlstra
2012-03-12 23:15                                     ` Paul E. McKenney
2012-03-12 23:18                                       ` Peter Zijlstra
2012-03-12 23:38                                         ` Paul E. McKenney
2012-03-06 15:26                     ` Lai Jiangshan
2012-03-06 15:37                       ` Peter Zijlstra
2012-03-06 11:17                   ` Peter Zijlstra
2012-03-06 11:22                   ` Peter Zijlstra
2012-03-06 11:35                   ` Peter Zijlstra
2012-03-06 11:36                   ` Peter Zijlstra
2012-03-06 11:39                   ` Peter Zijlstra
2012-03-06 14:50                     ` Lai Jiangshan
2012-03-06 11:52                   ` Peter Zijlstra
2012-03-06 14:44                     ` Lai Jiangshan
2012-03-06 15:31                       ` Peter Zijlstra
2012-03-06 15:32                       ` Peter Zijlstra
2012-03-07  6:44                         ` Lai Jiangshan
2012-03-07  8:10                       ` Gilad Ben-Yossef
2012-03-07  9:21                         ` Lai Jiangshan
2012-03-06 14:47                     ` Lai Jiangshan
2012-03-06  9:57                 ` [PATCH 6/6] add srcu torture test Lai Jiangshan
2012-03-08 19:03                 ` [PATCH 1/6] remove unused srcu_barrier() Paul E. McKenney

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