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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
To: linux-kernel@vger.kernel.org
Cc: mingo@kernel.org, jiangshanlai@gmail.com, dipankar@in.ibm.com,
	akpm@linux-foundation.org, mathieu.desnoyers@efficios.com,
	josh@joshtriplett.org, tglx@linutronix.de, peterz@infradead.org,
	rostedt@goodmis.org, dhowells@redhat.com, edumazet@google.com,
	dvhart@linux.intel.com, fweisbec@gmail.com, oleg@redhat.com,
	bobby.prani@gmail.com, Alexander Gordeev <agordeev@redhat.com>,
	"Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Subject: [PATCH tip/core/rcu 03/12] rcu: Remove superfluous local variable in rcu_init_geometry()
Date: Fri, 17 Jul 2015 15:30:54 -0700	[thread overview]
Message-ID: <1437172263-15466-3-git-send-email-paulmck@linux.vnet.ibm.com> (raw)
In-Reply-To: <1437172263-15466-1-git-send-email-paulmck@linux.vnet.ibm.com>

From: Alexander Gordeev <agordeev@redhat.com>

Local variable 'n' mimics 'nr_cpu_ids' while the both are
used within one function. There is no reason for 'n' to
exist whatsoever.

Cc: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Alexander Gordeev <agordeev@redhat.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
 kernel/rcu/tree.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index fe8d92987dfa..ad49dbed44fb 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -4083,7 +4083,6 @@ static void __init rcu_init_geometry(void)
 	ulong d;
 	int i;
 	int j;
-	int n = nr_cpu_ids;
 	int rcu_capacity[MAX_RCU_LVLS + 1];
 
 	/*
@@ -4133,15 +4132,16 @@ static void __init rcu_init_geometry(void)
 	 * The tree must be able to accommodate the configured number of CPUs.
 	 * If this limit is exceeded than we have a serious problem elsewhere.
 	 */
-	if (n > rcu_capacity[MAX_RCU_LVLS])
+	if (nr_cpu_ids > rcu_capacity[MAX_RCU_LVLS])
 		panic("rcu_init_geometry: rcu_capacity[] is too small");
 
 	/* Calculate the number of rcu_nodes at each level of the tree. */
 	for (i = 1; i <= MAX_RCU_LVLS; i++)
-		if (n <= rcu_capacity[i]) {
-			for (j = 0; j <= i; j++)
-				num_rcu_lvl[j] =
-					DIV_ROUND_UP(n, rcu_capacity[i - j]);
+		if (nr_cpu_ids <= rcu_capacity[i]) {
+			for (j = 0; j <= i; j++) {
+				int cap = rcu_capacity[i - j];
+				num_rcu_lvl[j] = DIV_ROUND_UP(nr_cpu_ids, cap);
+			}
 			rcu_num_lvls = i;
 			for (j = i + 1; j <= MAX_RCU_LVLS; j++)
 				num_rcu_lvl[j] = 0;
@@ -4152,7 +4152,7 @@ static void __init rcu_init_geometry(void)
 	rcu_num_nodes = 0;
 	for (i = 0; i <= MAX_RCU_LVLS; i++)
 		rcu_num_nodes += num_rcu_lvl[i];
-	rcu_num_nodes -= n;
+	rcu_num_nodes -= nr_cpu_ids;
 }
 
 /*
-- 
1.8.1.5


  parent reply	other threads:[~2015-07-17 22:33 UTC|newest]

Thread overview: 21+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2015-07-17 22:30 [PATCH tip/core/rcu 0/12] Tree geometry-initialization simplifications for 4.3 Paul E. McKenney
2015-07-17 22:30 ` [PATCH tip/core/rcu 01/12] rcu: Provide more diagnostics for stalled GP kthread Paul E. McKenney
2015-07-17 22:30   ` [PATCH tip/core/rcu 02/12] rcu: Panic if RCU tree can not accommodate all CPUs Paul E. McKenney
2015-07-30 12:28     ` Peter Zijlstra
2015-07-30 15:25       ` Paul E. McKenney
2015-07-30 15:32         ` Peter Zijlstra
2015-07-30 15:34           ` Peter Zijlstra
2015-07-30 16:01             ` Paul E. McKenney
2015-07-30 15:54           ` Paul E. McKenney
2015-07-30 16:22             ` Peter Zijlstra
2015-07-31 15:53               ` Paul E. McKenney
2015-07-17 22:30   ` Paul E. McKenney [this message]
2015-07-17 22:30   ` [PATCH tip/core/rcu 04/12] rcu: Cleanup rcu_init_geometry() code and arithmetics Paul E. McKenney
2015-07-17 22:30   ` [PATCH tip/core/rcu 05/12] rcu: Simplify rcu_init_geometry() capacity arithmetics Paul E. McKenney
2015-07-17 22:30   ` [PATCH tip/core/rcu 06/12] rcu: Limit rcu_state::levelcnt[] to RCU_NUM_LVLS items Paul E. McKenney
2015-07-17 22:30   ` [PATCH tip/core/rcu 07/12] rcu: Limit rcu_capacity[] size " Paul E. McKenney
2015-07-17 22:30   ` [PATCH tip/core/rcu 08/12] rcu: Remove unnecessary fields from rcu_state structure Paul E. McKenney
2015-07-17 22:31   ` [PATCH tip/core/rcu 09/12] rcu: Limit count of static data to the number of RCU levels Paul E. McKenney
2015-07-17 22:31   ` [PATCH tip/core/rcu 10/12] rcu: Simplify arithmetic to calculate number of RCU nodes Paul E. McKenney
2015-07-17 22:31   ` [PATCH tip/core/rcu 11/12] rcu: Shut up bogus gcc array bounds warning Paul E. McKenney
2015-07-17 22:31   ` [PATCH tip/core/rcu 12/12] rcu: Reset rcu_fanout_leaf if out of bounds Paul E. McKenney

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