From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753397AbbCIIeg (ORCPT ); Mon, 9 Mar 2015 04:34:36 -0400 Received: from mx1.redhat.com ([209.132.183.28]:36157 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753346AbbCIIe3 (ORCPT ); Mon, 9 Mar 2015 04:34:29 -0400 From: Alexander Gordeev To: linux-kernel@vger.kernel.org Cc: Alexander Gordeev , "Paul E. McKenney" Subject: [PATCH 06/10] rcu: Limit rcu_capacity[] size to RCU_NUM_LVLS items Date: Mon, 9 Mar 2015 09:34:10 +0100 Message-Id: In-Reply-To: References: Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Number of items in rcu_capacity[] array is defined by macro MAX_RCU_LVLS. However, that array is never accessed beyond RCU_NUM_LVLS index. Therefore, we can limit the array to RCU_NUM_LVLS items and eliminate MAX_RCU_LVLS. As result, in most cases the memory is conserved. Cc: "Paul E. McKenney" Signed-off-by: Alexander Gordeev --- kernel/rcu/tree.c | 12 ++++++------ kernel/rcu/tree.h | 1 - 2 files changed, 6 insertions(+), 7 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 98e36c3..dbcec66 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3924,19 +3924,19 @@ static void __init rcu_init_one(struct rcu_state *rsp, "rcu_node_0", "rcu_node_1", "rcu_node_2", - "rcu_node_3" }; /* Match MAX_RCU_LVLS */ + "rcu_node_3" }; static const char * const fqs[] = { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2", - "rcu_node_fqs_3" }; /* Match MAX_RCU_LVLS */ + "rcu_node_fqs_3" }; static u8 fl_mask = 0x1; int cpustride = 1; int i; int j; struct rcu_node *rnp; - BUILD_BUG_ON(MAX_RCU_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */ + BUILD_BUG_ON(RCU_NUM_LVLS > ARRAY_SIZE(buf)); /* Fix buf[] init! */ /* Silence gcc 4.8 warning about array index out of range. */ if (rcu_num_lvls > RCU_NUM_LVLS) @@ -4008,7 +4008,7 @@ static void __init rcu_init_geometry(void) { ulong d; int i; - int rcu_capacity[MAX_RCU_LVLS]; + int rcu_capacity[RCU_NUM_LVLS]; /* * Initialize any unspecified boot parameters. @@ -4035,7 +4035,7 @@ static void __init rcu_init_geometry(void) * with the given number of levels. */ rcu_capacity[0] = rcu_fanout_leaf; - for (i = 1; i < MAX_RCU_LVLS; i++) + for (i = 1; i < RCU_NUM_LVLS; i++) rcu_capacity[i] = rcu_capacity[i - 1] * CONFIG_RCU_FANOUT; /* @@ -4048,7 +4048,7 @@ static void __init rcu_init_geometry(void) * the rcu_node masks. Complain and fall back to the compile- * time values if these limits are exceeded. */ - if (nr_cpu_ids > rcu_capacity[MAX_RCU_LVLS - 1]) + if (nr_cpu_ids > rcu_capacity[RCU_NUM_LVLS - 1]) panic("rcu_init_geometry: rcu_capacity[] is too small"); else if (rcu_fanout_leaf < CONFIG_RCU_FANOUT_LEAF || rcu_fanout_leaf > sizeof(unsigned long) * 8) { diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index f358a83..661d2d4 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -35,7 +35,6 @@ * In practice, this did work well going from three levels to four. * Of course, your mileage may vary. */ -#define MAX_RCU_LVLS 4 #define RCU_FANOUT_1 (CONFIG_RCU_FANOUT_LEAF) #define RCU_FANOUT_2 (RCU_FANOUT_1 * CONFIG_RCU_FANOUT) #define RCU_FANOUT_3 (RCU_FANOUT_2 * CONFIG_RCU_FANOUT) -- 1.8.3.1