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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-03-14 12:42:30 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2017-04-18 11:38:20 -0700
commitf2425b4efb0c69e77c0b9666b605ae4a1ecaae47 (patch)
tree01bf661bcaba584f013e151a10099b250425a21b /kernel
parent8660b7d8a545227fd9ee80508aa82528ea9947d7 (diff)
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srcu: Move combining-tree definitions for SRCU's benefit
This commit moves the C preprocessor code that defines the default shape of the rcu_node combining tree to a new include/linux/rcu_node_tree.h file as a first step towards enabling SRCU to create its own combining tree, which in turn enables SRCU to implement per-CPU callback handling, thus avoiding contention on the lock currently guarding the single list of callbacks. Note that users of SRCU still need to know the size of the srcu_struct structure, hence include/linux rather than kernel/rcu. This commit is code-movement only. Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel')
-rw-r--r--kernel/rcu/tree.h71
1 files changed, 1 insertions, 70 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index 4f62651588ea..1bec3958d44f 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -31,76 +31,7 @@
#include <linux/swait.h>
#include <linux/stop_machine.h>
#include <linux/rcu_segcblist.h>
-
-/*
- * Define shape of hierarchy based on NR_CPUS, CONFIG_RCU_FANOUT, and
- * CONFIG_RCU_FANOUT_LEAF.
- * In theory, it should be possible to add more levels straightforwardly.
- * In practice, this did work well going from three levels to four.
- * Of course, your mileage may vary.
- */
-
-#ifdef CONFIG_RCU_FANOUT
-#define RCU_FANOUT CONFIG_RCU_FANOUT
-#else /* #ifdef CONFIG_RCU_FANOUT */
-# ifdef CONFIG_64BIT
-# define RCU_FANOUT 64
-# else
-# define RCU_FANOUT 32
-# endif
-#endif /* #else #ifdef CONFIG_RCU_FANOUT */
-
-#ifdef CONFIG_RCU_FANOUT_LEAF
-#define RCU_FANOUT_LEAF CONFIG_RCU_FANOUT_LEAF
-#else /* #ifdef CONFIG_RCU_FANOUT_LEAF */
-#define RCU_FANOUT_LEAF 16
-#endif /* #else #ifdef CONFIG_RCU_FANOUT_LEAF */
-
-#define RCU_FANOUT_1 (RCU_FANOUT_LEAF)
-#define RCU_FANOUT_2 (RCU_FANOUT_1 * RCU_FANOUT)
-#define RCU_FANOUT_3 (RCU_FANOUT_2 * RCU_FANOUT)
-#define RCU_FANOUT_4 (RCU_FANOUT_3 * RCU_FANOUT)
-
-#if NR_CPUS <= RCU_FANOUT_1
-# define RCU_NUM_LVLS 1
-# define NUM_RCU_LVL_0 1
-# 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" }
-#elif NR_CPUS <= RCU_FANOUT_2
-# 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_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" }
-#elif NR_CPUS <= RCU_FANOUT_3
-# define RCU_NUM_LVLS 3
-# 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_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" }
-#elif NR_CPUS <= RCU_FANOUT_4
-# define RCU_NUM_LVLS 4
-# define NUM_RCU_LVL_0 1
-# 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_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" }
-#else
-# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
-#endif /* #if (NR_CPUS) <= RCU_FANOUT_1 */
-
-extern int rcu_num_lvls;
-extern int rcu_num_nodes;
+#include <linux/rcu_node_tree.h>
/*
* Dynticks per-CPU state.