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 10/12] rcu: Simplify arithmetic to calculate number of RCU nodes
Date: Fri, 17 Jul 2015 15:31:01 -0700 [thread overview]
Message-ID: <1437172263-15466-10-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>
This update makes arithmetic to calculate number of RCU nodes
more straight and easy to read.
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.h | 17 ++++-------------
kernel/rcu/tree_plugin.h | 4 ++--
2 files changed, 6 insertions(+), 15 deletions(-)
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index d44856b6170a..581f8d3c5b28 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -64,10 +64,7 @@
#if NR_CPUS <= RCU_FANOUT_1
# define RCU_NUM_LVLS 1
# define NUM_RCU_LVL_0 1
-# define NUM_RCU_LVL_1 (NR_CPUS)
-# define NUM_RCU_LVL_2 0
-# define NUM_RCU_LVL_3 0
-# define NUM_RCU_LVL_4 0
+# define NUM_RCU_NODES NUM_RCU_LVL_0
# define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0 }
# define RCU_NODE_NAME_INIT { "rcu_node_0" }
# define RCU_FQS_NAME_INIT { "rcu_node_fqs_0" }
@@ -75,9 +72,7 @@
# define RCU_NUM_LVLS 2
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
-# define NUM_RCU_LVL_2 (NR_CPUS)
-# define NUM_RCU_LVL_3 0
-# define NUM_RCU_LVL_4 0
+# define NUM_RCU_NODES (NUM_RCU_LVL_0 + NUM_RCU_LVL_1)
# define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0, NUM_RCU_LVL_1 }
# define RCU_NODE_NAME_INIT { "rcu_node_0", "rcu_node_1" }
# define RCU_FQS_NAME_INIT { "rcu_node_fqs_0", "rcu_node_fqs_1" }
@@ -86,8 +81,7 @@
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
-# define NUM_RCU_LVL_3 (NR_CPUS)
-# define NUM_RCU_LVL_4 0
+# define NUM_RCU_NODES (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2)
# define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2 }
# define RCU_NODE_NAME_INIT { "rcu_node_0", "rcu_node_1", "rcu_node_2" }
# define RCU_FQS_NAME_INIT { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2" }
@@ -97,7 +91,7 @@
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_3)
# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_2)
# define NUM_RCU_LVL_3 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_1)
-# define NUM_RCU_LVL_4 (NR_CPUS)
+# define NUM_RCU_NODES (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3)
# define NUM_RCU_LVL_INIT { NUM_RCU_LVL_0, NUM_RCU_LVL_1, NUM_RCU_LVL_2, NUM_RCU_LVL_3 }
# define RCU_NODE_NAME_INIT { "rcu_node_0", "rcu_node_1", "rcu_node_2", "rcu_node_3" }
# define RCU_FQS_NAME_INIT { "rcu_node_fqs_0", "rcu_node_fqs_1", "rcu_node_fqs_2", "rcu_node_fqs_3" }
@@ -105,9 +99,6 @@
# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
#endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */
-#define RCU_SUM (NUM_RCU_LVL_0 + NUM_RCU_LVL_1 + NUM_RCU_LVL_2 + NUM_RCU_LVL_3 + NUM_RCU_LVL_4)
-#define NUM_RCU_NODES (RCU_SUM - NR_CPUS)
-
extern int rcu_num_lvls;
extern int rcu_num_nodes;
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 013485fb2b06..5dac0a10a985 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -84,8 +84,8 @@ static void __init rcu_bootup_announce_oddness(void)
pr_info("\tRCU torture testing starts during boot.\n");
if (IS_ENABLED(CONFIG_RCU_CPU_STALL_INFO))
pr_info("\tAdditional per-CPU info printed with stalls.\n");
- if (NUM_RCU_LVL_4 != 0)
- pr_info("\tFour-level hierarchy is enabled.\n");
+ if (RCU_NUM_LVLS >= 4)
+ pr_info("\tFour(or more)-level hierarchy is enabled.\n");
if (RCU_FANOUT_LEAF != 16)
pr_info("\tBuild-time adjustment of leaf fanout to %d.\n",
RCU_FANOUT_LEAF);
--
1.8.1.5
next prev parent reply other threads:[~2015-07-17 22:31 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 ` [PATCH tip/core/rcu 03/12] rcu: Remove superfluous local variable in rcu_init_geometry() Paul E. McKenney
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 ` Paul E. McKenney [this message]
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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