linux-kernel - [PATCH 7/9] rcu: Remove unnecessary fields from rcu

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Message-Id: <8637cfbbd2a602a6ba9426cbd2321fb316b162de.1425735920.git.agordeev@redhat.com>
Date:	Sat,  7 Mar 2015 18:03:42 +0100
From:	Alexander Gordeev <agordeev@...hat.com>
To:	linux-kernel@...r.kernel.org
Cc:	Alexander Gordeev <agordeev@...hat.com>,
	"Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Subject: [PATCH 7/9] rcu: Remove unnecessary fields from rcu_state structure

Members rcu_state::levelcnt[] and rcu_state::levelspread[]
are only used at init. There is no reason to keep them
afterwards.

Cc: "Paul E. McKenney" <paulmck@...ux.vnet.ibm.com>
Signed-off-by: Alexander Gordeev <agordeev@...hat.com>
---
 kernel/rcu/tree.c | 29 ++++++++++++++++-------------
 kernel/rcu/tree.h |  2 --
 2 files changed, 16 insertions(+), 15 deletions(-)

diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c
index 6856096..ccea2c7 100644
--- a/kernel/rcu/tree.c
+++ b/kernel/rcu/tree.c
@@ -3735,16 +3735,16 @@ void rcu_scheduler_starting(void)
  * or balancing the tree, depending on CONFIG_RCU_FANOUT_EXACT.
  */
 #ifdef CONFIG_RCU_FANOUT_EXACT
-static void __init rcu_init_levelspread(struct rcu_state *rsp)
+static void __init rcu_init_levelspread(int *levelspread, const int *levelcnt)
 {
 	int i;
 
-	rsp->levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
+	levelspread[rcu_num_lvls - 1] = rcu_fanout_leaf;
 	for (i = rcu_num_lvls - 2; i >= 0; i--)
-		rsp->levelspread[i] = CONFIG_RCU_FANOUT;
+		levelspread[i] = CONFIG_RCU_FANOUT;
 }
 #else /* #ifdef CONFIG_RCU_FANOUT_EXACT */
-static void __init rcu_init_levelspread(struct rcu_state *rsp)
+static void __init rcu_init_levelspread(int *levelspread, const int *levelcnt)
 {
 	int ccur;
 	int cprv;
@@ -3752,8 +3752,8 @@ static void __init rcu_init_levelspread(struct rcu_state *rsp)
 
 	cprv = nr_cpu_ids;
 	for (i = rcu_num_lvls - 1; i >= 0; i--) {
-		ccur = rsp->levelcnt[i];
-		rsp->levelspread[i] = (cprv + ccur - 1) / ccur;
+		ccur = levelcnt[i];
+		levelspread[i] = (cprv + ccur - 1) / ccur;
 		cprv = ccur;
 	}
 }
@@ -3776,6 +3776,9 @@ static void __init rcu_init_one(struct rcu_state *rsp,
 		"rcu_node_fqs_2",
 		"rcu_node_fqs_3" };
 	static u8 fl_mask = 0x1;
+
+	int levelcnt[RCU_NUM_LVLS];		/* # nodes in each level. */
+	int levelspread[RCU_NUM_LVLS];		/* kids/node in each level. */
 	int cpustride = 1;
 	int i;
 	int j;
@@ -3790,19 +3793,19 @@ static void __init rcu_init_one(struct rcu_state *rsp,
 	/* Initialize the level-tracking arrays. */
 
 	for (i = 0; i < rcu_num_lvls; i++)
-		rsp->levelcnt[i] = num_rcu_lvl[i];
+		levelcnt[i] = num_rcu_lvl[i];
 	for (i = 1; i < rcu_num_lvls; i++)
-		rsp->level[i] = rsp->level[i - 1] + rsp->levelcnt[i - 1];
-	rcu_init_levelspread(rsp);
+		rsp->level[i] = rsp->level[i - 1] + levelcnt[i - 1];
+	rcu_init_levelspread(levelspread, levelcnt);
 	rsp->flavor_mask = fl_mask;
 	fl_mask <<= 1;
 
 	/* Initialize the elements themselves, starting from the leaves. */
 
 	for (i = rcu_num_lvls - 1; i >= 0; i--) {
-		cpustride *= rsp->levelspread[i];
+		cpustride *= levelspread[i];
 		rnp = rsp->level[i];
-		for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) {
+		for (j = 0; j < levelcnt[i]; j++, rnp++) {
 			raw_spin_lock_init(&rnp->lock);
 			lockdep_set_class_and_name(&rnp->lock,
 						   &rcu_node_class[i], buf[i]);
@@ -3822,10 +3825,10 @@ static void __init rcu_init_one(struct rcu_state *rsp,
 				rnp->grpmask = 0;
 				rnp->parent = NULL;
 			} else {
-				rnp->grpnum = j % rsp->levelspread[i - 1];
+				rnp->grpnum = j % levelspread[i - 1];
 				rnp->grpmask = 1UL << rnp->grpnum;
 				rnp->parent = rsp->level[i - 1] +
-					      j / rsp->levelspread[i - 1];
+					      j / levelspread[i - 1];
 			}
 			rnp->level = i;
 			INIT_LIST_HEAD(&rnp->blkd_tasks);
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 0f7a469..a3e4714 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -414,8 +414,6 @@ do {									\
 struct rcu_state {
 	struct rcu_node node[NUM_RCU_NODES];	/* Hierarchy. */
 	struct rcu_node *level[RCU_NUM_LVLS];	/* Hierarchy levels. */
-	u32 levelcnt[RCU_NUM_LVLS];		/* # nodes in each level. */
-	u8 levelspread[RCU_NUM_LVLS];		/* kids/node in each level. */
 	u8 flavor_mask;				/* bit in flavor mask. */
 	struct rcu_data __percpu *rda;		/* pointer of percu rcu_data. */
 	void (*call)(struct rcu_head *head,	/* call_rcu() flavor. */
-- 
1.8.3.1

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