[userspace-rcu.git] / rcuja / rcuja.c

/*
 * rcuja/rcuja.c
 *
 * Userspace RCU library - RCU Judy Array
 *
 * Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 *
 * This library is free software; you can redistribute it and/or
 * modify it under the terms of the GNU Lesser General Public
 * License as published by the Free Software Foundation; either
 * version 2.1 of the License, or (at your option) any later version.
 *
 * This library is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * Lesser General Public License for more details.
 *
 * You should have received a copy of the GNU Lesser General Public
 * License along with this library; if not, write to the Free Software
 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
 */

#include <stdint.h>
#include <limits.h>
#include <urcu/rcuja.h>
#include <urcu/compiler.h>
#include <urcu/arch.h>
#include <assert.h>
#include "rcuja-internal.h"
#include "bitfield.h"

enum rcu_ja_type_class {
	RCU_JA_LINEAR = 0,	/* Type A */
			/* 32-bit: 1 to 25 children, 8 to 128 bytes */
			/* 64-bit: 1 to 28 children, 16 to 256 bytes */
	RCU_JA_POOL = 1,	/* Type B */
			/* 32-bit: 26 to 100 children, 256 to 512 bytes */
			/* 64-bit: 29 to 112 children, 512 to 1024 bytes */
	RCU_JA_PIGEON = 2,	/* Type C */
			/* 32-bit: 101 to 256 children, 1024 bytes */
			/* 64-bit: 113 to 256 children, 2048 bytes */
	/* Leaf nodes are implicit from their height in the tree */
	RCU_JA_NR_TYPES,
};

struct rcu_ja_type {
	enum rcu_ja_type_class type_class;
	uint16_t min_child;	/* minimum number of children: 1 to 256 */
	uint16_t max_child;	/* maximum number of children: 1 to 256 */
	uint16_t order;		/* node size is (1 << order), in bytes */
	uint16_t nr_pool_order;		/* number of pools */
	uint16_t pool_size_order;	/* pool size */
};

/*
 * Number of least significant pointer bits reserved to represent the
 * child type.
 */
#define JA_TYPE_BITS	3
#define JA_TYPE_MAX_NR	(1U << JA_TYPE_BITS)
#define JA_TYPE_MASK	(JA_TYPE_MAX_NR - 1)
#define JA_PTR_MASK	(~JA_TYPE_MASK)

#define JA_ENTRY_PER_NODE	256UL

/*
 * Iteration on the array to find the right node size for the number of
 * children stops when it reaches .max_child == 256 (this is the largest
 * possible node size, which contains 256 children).
 * The min_child overlaps with the previous max_child to provide an
 * hysteresis loop to reallocation for patterns of cyclic add/removal
 * within the same node.
 * The node the index within the following arrays is represented on 3
 * bits. It identifies the node type, min/max number of children, and
 * the size order.
 * The max_child values for the RCU_JA_POOL below result from
 * statistical approximation: over million populations, the max_child
 * covers between 97% and 99% of the populations generated. Therefore, a
 * fallback should exist to cover the rare extreme population unbalance
 * cases, but it will not have a major impact on speed nor space
 * consumption, since those are rare cases.
 */

#if (CAA_BITS_PER_LONG < 64)
/* 32-bit pointers */
enum {
	ja_type_0_max_child = 1,
	ja_type_1_max_child = 3,
	ja_type_2_max_child = 6,
	ja_type_3_max_child = 12,
	ja_type_4_max_child = 25,
	ja_type_5_max_child = 48,
	ja_type_6_max_child = 92,
	ja_type_7_max_child = 256,
};

enum {
	ja_type_5_nr_pool_order = 1,
	ja_type_6_nr_pool_order = 2,
};

const struct rcu_ja_type ja_types[] = {
	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 3, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 4, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 5, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = ja_type_3_max_child, .order = 6, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 7, },

	/* Pools may fill sooner than max_child */
	{ .type_class = RCU_JA_POOL, .min_child = 20, .max_child = ja_type_5_max_child, .order = 8, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 7, },
	{ .type_class = RCU_JA_POOL, .min_child = 45, .max_child = ja_type_6_max_child, .order = 9, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 7, },

	/*
	 * TODO: Upon node removal below min_child, if child pool is
	 * filled beyond capacity, we need to roll back to pigeon.
	 */
	{ .type_class = RCU_JA_PIGEON, .min_child = 89, .max_child = ja_type_7_max_child, .order = 10, },
};
#else /* !(CAA_BITS_PER_LONG < 64) */
/* 64-bit pointers */
enum {
	ja_type_0_max_child = 1,
	ja_type_1_max_child = 3,
	ja_type_2_max_child = 7,
	ja_type_3_max_child = 14,
	ja_type_4_max_child = 28,
	ja_type_5_max_child = 54,
	ja_type_6_max_child = 104,
	ja_type_7_max_child = 256,
};

enum {
	ja_type_5_nr_pool_order = 1,
	ja_type_6_nr_pool_order = 2,
};

const struct rcu_ja_type ja_types[] = {
	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 4, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 5, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 6, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = ja_type_3_max_child, .order = 7, },
	{ .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 8, },

	/* Pools may fill sooner than max_child. */
	{ .type_class = RCU_JA_POOL, .min_child = 22, .max_child = ja_type_5_max_child, .order = 9, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 8, },
	{ .type_class = RCU_JA_POOL, .min_child = 51, .max_child = ja_type_6_max_child, .order = 10, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 8, },

	/*
	 * TODO: Upon node removal below min_child, if child pool is
	 * filled beyond capacity, we need to roll back to pigeon.
	 */
	{ .type_class = RCU_JA_PIGEON, .min_child = 101, .max_child = ja_type_7_max_child, .order = 11, },
};
#endif /* !(BITS_PER_LONG < 64) */

static inline __attribute__((unused))
void static_array_size_check(void)
{
	CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) > JA_TYPE_MAX_NR);
}

/* Never declared. Opaque type used to store flagged node pointers. */
struct rcu_ja_node_flag;

/*
 * The rcu_ja_node contains the compressed node data needed for
 * read-side. For linear and pool node configurations, it starts with a
 * byte counting the number of children in the node.  Then, the
 * node-specific data is placed.
 * The node mutex, if any is needed, protecting concurrent updated of
 * each node is placed in a separate hash table indexed by node address.
 * For the pigeon configuration, the number of children is also kept in
 * a separate hash table, indexed by node address, because it is only
 * required for updates.
 */

#define DECLARE_LINEAR_NODE(index)									\
		struct {										\
			uint8_t nr_child;								\
			uint8_t child_value[ja_type_## index ##_max_child];				\
			struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child];			\
		}

#define DECLARE_POOL_NODE(index)									\
		struct {										\
			struct {									\
				uint8_t nr_child;							\
				uint8_t child_value[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \
				struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \
			} linear[1U << ja_type_## index ##_nr_pool_order];				\
		}

struct rcu_ja_node {
	union {
		/* Linear configuration */
		DECLARE_LINEAR_NODE(0) conf_0;
		DECLARE_LINEAR_NODE(1) conf_1;
		DECLARE_LINEAR_NODE(2) conf_2;
		DECLARE_LINEAR_NODE(3) conf_3;
		DECLARE_LINEAR_NODE(4) conf_4;

		/* Pool configuration */
		DECLARE_POOL_NODE(5) conf_5;
		DECLARE_POOL_NODE(6) conf_6;

		/* Pigeon configuration */
		struct {
			struct rcu_ja_node_flag *child[ja_type_7_max_child];
		} conf_7;
		/* data aliasing nodes for computed accesses */
		uint8_t data[sizeof(struct rcu_ja_node_flag *) * ja_type_7_max_child];
	} u;
};

static
struct rcu_ja_node_flag *ja_node_flag(struct rcu_ja_node *node, unsigned int type)
{
	assert(type < RCU_JA_NR_TYPES);
	return (struct rcu_ja_node_flag *) (((unsigned long) node) | type);
}

static
unsigned int ja_node_type(struct rcu_ja_node_flag *node)
{
	unsigned int type;

	type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
	assert(type < RCU_JA_NR_TYPES);
	return type;
}

static
struct rcu_ja_node *ja_node_ptr(struct rcu_ja_node_flag *node)
{
	return (struct rcu_ja_node *) (((unsigned long) node) | JA_PTR_MASK);
}

struct rcu_ja_node *alloc_rcu_ja_node(struct rcu_ja_type *ja_type)
{
	return calloc(1U << ja_type->order, sizeof(char));
}

void free_rcu_ja_node(struct rcu_ja_node *node)
{
	free(node);
}

#define __JA_ALIGN_MASK(v, mask)	(((v) + (mask)) & ~(mask))
#define JA_ALIGN(v, align)		__JA_ALIGN_MASK(v, (typeof(v)) (align) - 1)
#define __JA_FLOOR_MASK(v, mask)	((v) & ~(mask))
#define JA_FLOOR(v, align)		__JA_FLOOR_MASK(v, (typeof(v)) (align) - 1)

static
uint8_t *align_ptr_size(uint8_t *ptr)
{
	return (uint8_t *) JA_ALIGN((unsigned long) ptr, sizeof(void *));
}

static
struct rcu_ja_node_flag *ja_linear_node_get_nth(const struct rcu_ja_type *type,
					struct rcu_ja_node *node,
					uint8_t n)
{
	uint8_t nr_child;
	uint8_t *values;
	struct rcu_ja_node_flag **pointers;
	struct rcu_ja_node_flag *ptr;
	unsigned int i;

	assert(!type || type->type_class == RCU_JA_LINEAR);

	nr_child = node->u.data[0];
	cmm_smp_rmb();	/* read nr_child before values */
	assert(!type || nr_child <= type->max_child);
	assert(!type || nr_child >= type->min_child);

	values = &node->u.data[1];
	for (i = 0; i < nr_child; i++) {
		if (values[i] == n)
			break;
	}
	if (i >= nr_child)
		return NULL;
	cmm_smp_rmb();	/* read values before pointer */
	pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[nr_child]);
	ptr = pointers[i];
	assert(ja_node_ptr(ptr) != NULL);
	return ptr;
}

static
struct rcu_ja_node_flag *ja_pool_node_get_nth(const struct rcu_ja_type *type,
					struct rcu_ja_node *node,
					uint8_t n)
{
	struct rcu_ja_node *linear;

	assert(type->type_class == RCU_JA_POOL);
	linear = (struct rcu_ja_node *)
		&node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
	return ja_linear_node_get_nth(NULL, linear, n);
}

static
struct rcu_ja_node_flag *ja_pigeon_node_get_nth(const struct rcu_ja_type *type,
					struct rcu_ja_node *node,
					uint8_t n)
{
	assert(type->type_class == RCU_JA_PIGEON);
	return ((struct rcu_ja_node_flag **) node->u.data)[n];
}

/* ja_node_get_nth: get nth item from a node */
static
struct rcu_ja_node_flag *ja_node_get_nth(struct rcu_ja_node_flag *node_flag,
					uint8_t n)
{
	unsigned int type_index;
	struct rcu_ja_node *node;
	const struct rcu_ja_type *type;

	node_flag = rcu_dereference(node_flag);
	node = ja_node_ptr(node_flag);
	assert(node != NULL);
	type_index = ja_node_type(node_flag);
	type = &ja_types[type_index];

	switch (type->type_class) {
	case RCU_JA_LINEAR:
		return ja_linear_node_get_nth(type, node, n);
	case RCU_JA_POOL:
		return ja_pool_node_get_nth(type, node, n);
	case RCU_JA_PIGEON:
		return ja_pigeon_node_get_nth(type, node, n);
	default:
		assert(0);
		return (void *) -1UL;
	}
}

/*
 * ja_node_set_nth: set nth item within a node. asserts that it is not
 * there yet.
 */
Commit	Line	Data
61009379 MD	1	/*
	2	* rcuja/rcuja.c
	3	*
	4	* Userspace RCU library - RCU Judy Array
	5	*
	6	* Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	7	*
	8	* This library is free software; you can redistribute it and/or
	9	* modify it under the terms of the GNU Lesser General Public
	10	* License as published by the Free Software Foundation; either
	11	* version 2.1 of the License, or (at your option) any later version.
	12	*
	13	* This library is distributed in the hope that it will be useful,
	14	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	15	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	16	* Lesser General Public License for more details.
	17	*
	18	* You should have received a copy of the GNU Lesser General Public
	19	* License along with this library; if not, write to the Free Software
	20	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	21	*/
	22
e5227865	23	#include <stdint.h>
d68c6810	24	#include <limits.h>
61009379	25	#include <urcu/rcuja.h>
d68c6810 MD	26	#include <urcu/compiler.h>
	27	#include <urcu/arch.h>
	28	#include <assert.h>
61009379	29	#include "rcuja-internal.h"
d68c6810	30	#include "bitfield.h"
61009379	31
d68c6810	32	enum rcu_ja_type_class {
e5227865	33	RCU_JA_LINEAR = 0, /* Type A */
fd800776 MD	34	/* 32-bit: 1 to 25 children, 8 to 128 bytes */
	35	/* 64-bit: 1 to 28 children, 16 to 256 bytes */
	36	RCU_JA_POOL = 1, /* Type B */
	37	/* 32-bit: 26 to 100 children, 256 to 512 bytes */
	38	/* 64-bit: 29 to 112 children, 512 to 1024 bytes */
e5227865	39	RCU_JA_PIGEON = 2, /* Type C */
fd800776 MD	40	/* 32-bit: 101 to 256 children, 1024 bytes */
fd800776 MD	41	/* 64-bit: 113 to 256 children, 2048 bytes */
e5227865	42	/* Leaf nodes are implicit from their height in the tree */
1db4943c	43	RCU_JA_NR_TYPES,
e5227865 MD	44	};
e5227865 MD	45
d68c6810 MD	46	struct rcu_ja_type {
	47	enum rcu_ja_type_class type_class;
	48	uint16_t min_child; /* minimum number of children: 1 to 256 */
	49	uint16_t max_child; /* maximum number of children: 1 to 256 */
	50	uint16_t order; /* node size is (1 << order), in bytes */
fd800776 MD	51	uint16_t nr_pool_order; /* number of pools */
fd800776 MD	52	uint16_t pool_size_order; /* pool size */
e5227865 MD	53	};
e5227865 MD	54
d68c6810 MD	55	/*
	56	* Number of least significant pointer bits reserved to represent the
	57	* child type.
	58	*/
	59	#define JA_TYPE_BITS 3
	60	#define JA_TYPE_MAX_NR (1U << JA_TYPE_BITS)
	61	#define JA_TYPE_MASK (JA_TYPE_MAX_NR - 1)
	62	#define JA_PTR_MASK (~JA_TYPE_MASK)
	63
	64	#define JA_ENTRY_PER_NODE 256UL
	65
e5227865 MD	66	/*
e5227865 MD	67	* Iteration on the array to find the right node size for the number of
d68c6810	68	* children stops when it reaches .max_child == 256 (this is the largest
e5227865	69	* possible node size, which contains 256 children).
d68c6810 MD	70	* The min_child overlaps with the previous max_child to provide an
	71	* hysteresis loop to reallocation for patterns of cyclic add/removal
	72	* within the same node.
	73	* The node the index within the following arrays is represented on 3
	74	* bits. It identifies the node type, min/max number of children, and
	75	* the size order.
3d45251f MD	76	* The max_child values for the RCU_JA_POOL below result from
	77	* statistical approximation: over million populations, the max_child
	78	* covers between 97% and 99% of the populations generated. Therefore, a
	79	* fallback should exist to cover the rare extreme population unbalance
	80	* cases, but it will not have a major impact on speed nor space
	81	* consumption, since those are rare cases.
e5227865	82	*/
e5227865	83
d68c6810 MD	84	#if (CAA_BITS_PER_LONG < 64)
d68c6810 MD	85	/* 32-bit pointers */
1db4943c MD	86	enum {
	87	ja_type_0_max_child = 1,
	88	ja_type_1_max_child = 3,
	89	ja_type_2_max_child = 6,
	90	ja_type_3_max_child = 12,
	91	ja_type_4_max_child = 25,
	92	ja_type_5_max_child = 48,
	93	ja_type_6_max_child = 92,
	94	ja_type_7_max_child = 256,
	95	};
	96
	97	enum {
	98	ja_type_5_nr_pool_order = 1,
	99	ja_type_6_nr_pool_order = 2,
	100	};
	101
d68c6810	102	const struct rcu_ja_type ja_types[] = {
1db4943c MD	103	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 3, },
	104	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 4, },
	105	{ .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 5, },
	106	{ .type_class = RCU_JA_LINEAR, .min_child = 4, .max_child = ja_type_3_max_child, .order = 6, },
	107	{ .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 7, },
e5227865	108
fd800776	109	/* Pools may fill sooner than max_child */
1db4943c MD	110	{ .type_class = RCU_JA_POOL, .min_child = 20, .max_child = ja_type_5_max_child, .order = 8, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 7, },
1db4943c MD	111	{ .type_class = RCU_JA_POOL, .min_child = 45, .max_child = ja_type_6_max_child, .order = 9, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 7, },
3d45251f MD	112
	113	/*
	114	* TODO: Upon node removal below min_child, if child pool is
	115	* filled beyond capacity, we need to roll back to pigeon.
	116	*/
1db4943c	117	{ .type_class = RCU_JA_PIGEON, .min_child = 89, .max_child = ja_type_7_max_child, .order = 10, },
d68c6810	118	};
d68c6810 MD	119	#else /* !(CAA_BITS_PER_LONG < 64) */
d68c6810 MD	120	/* 64-bit pointers */
1db4943c MD	121	enum {
	122	ja_type_0_max_child = 1,
	123	ja_type_1_max_child = 3,
	124	ja_type_2_max_child = 7,
	125	ja_type_3_max_child = 14,
	126	ja_type_4_max_child = 28,
	127	ja_type_5_max_child = 54,
	128	ja_type_6_max_child = 104,
	129	ja_type_7_max_child = 256,
	130	};
	131
	132	enum {
	133	ja_type_5_nr_pool_order = 1,
	134	ja_type_6_nr_pool_order = 2,
	135	};
	136
d68c6810	137	const struct rcu_ja_type ja_types[] = {
1db4943c MD	138	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_0_max_child, .order = 4, },
	139	{ .type_class = RCU_JA_LINEAR, .min_child = 1, .max_child = ja_type_1_max_child, .order = 5, },
	140	{ .type_class = RCU_JA_LINEAR, .min_child = 3, .max_child = ja_type_2_max_child, .order = 6, },
	141	{ .type_class = RCU_JA_LINEAR, .min_child = 5, .max_child = ja_type_3_max_child, .order = 7, },
	142	{ .type_class = RCU_JA_LINEAR, .min_child = 10, .max_child = ja_type_4_max_child, .order = 8, },
e5227865	143
3d45251f	144	/* Pools may fill sooner than max_child. */
1db4943c MD	145	{ .type_class = RCU_JA_POOL, .min_child = 22, .max_child = ja_type_5_max_child, .order = 9, .nr_pool_order = ja_type_5_nr_pool_order, .pool_size_order = 8, },
1db4943c MD	146	{ .type_class = RCU_JA_POOL, .min_child = 51, .max_child = ja_type_6_max_child, .order = 10, .nr_pool_order = ja_type_6_nr_pool_order, .pool_size_order = 8, },
e5227865	147
3d45251f MD	148	/*
	149	* TODO: Upon node removal below min_child, if child pool is
	150	* filled beyond capacity, we need to roll back to pigeon.
	151	*/
1db4943c	152	{ .type_class = RCU_JA_PIGEON, .min_child = 101, .max_child = ja_type_7_max_child, .order = 11, },
e5227865	153	};
d68c6810	154	#endif /* !(BITS_PER_LONG < 64) */
e5227865	155
1db4943c MD	156	static inline __attribute__((unused))
	157	void static_array_size_check(void)
	158	{
	159	CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types) > JA_TYPE_MAX_NR);
	160	}
	161
	162	/* Never declared. Opaque type used to store flagged node pointers. */
	163	struct rcu_ja_node_flag;
	164
e5227865	165	/*
1db4943c MD	166	* The rcu_ja_node contains the compressed node data needed for
	167	* read-side. For linear and pool node configurations, it starts with a
	168	* byte counting the number of children in the node. Then, the
	169	* node-specific data is placed.
	170	* The node mutex, if any is needed, protecting concurrent updated of
	171	* each node is placed in a separate hash table indexed by node address.
	172	* For the pigeon configuration, the number of children is also kept in
	173	* a separate hash table, indexed by node address, because it is only
	174	* required for updates.
e5227865	175	*/
1db4943c MD	176
	177	#define DECLARE_LINEAR_NODE(index) \
	178	struct { \
	179	uint8_t nr_child; \
	180	uint8_t child_value[ja_type_## index ##_max_child]; \
	181	struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child]; \
	182	}
	183
	184	#define DECLARE_POOL_NODE(index) \
	185	struct { \
	186	struct { \
	187	uint8_t nr_child; \
	188	uint8_t child_value[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \
	189	struct rcu_ja_node_flag *child_ptr[ja_type_## index ##_max_child >> ja_type_## index ##_nr_pool_order]; \
	190	} linear[1U << ja_type_## index ##_nr_pool_order]; \
	191	}
	192
e5227865	193	struct rcu_ja_node {
1db4943c MD	194	union {
	195	/* Linear configuration */
	196	DECLARE_LINEAR_NODE(0) conf_0;
	197	DECLARE_LINEAR_NODE(1) conf_1;
	198	DECLARE_LINEAR_NODE(2) conf_2;
	199	DECLARE_LINEAR_NODE(3) conf_3;
	200	DECLARE_LINEAR_NODE(4) conf_4;
	201
	202	/* Pool configuration */
	203	DECLARE_POOL_NODE(5) conf_5;
	204	DECLARE_POOL_NODE(6) conf_6;
	205
	206	/* Pigeon configuration */
	207	struct {
	208	struct rcu_ja_node_flag *child[ja_type_7_max_child];
	209	} conf_7;
	210	/* data aliasing nodes for computed accesses */
	211	uint8_t data[sizeof(struct rcu_ja_node_flag ) ja_type_7_max_child];
	212	} u;
e5227865 MD	213	};
e5227865 MD	214
d68c6810 MD	215	static
	216	struct rcu_ja_node_flag ja_node_flag(struct rcu_ja_node node, unsigned int type)
	217	{
1db4943c	218	assert(type < RCU_JA_NR_TYPES);
d68c6810 MD	219	return (struct rcu_ja_node_flag *) (((unsigned long) node) \| type);
	220	}
	221
	222	static
	223	unsigned int ja_node_type(struct rcu_ja_node_flag *node)
	224	{
	225	unsigned int type;
	226
	227	type = (unsigned int) ((unsigned long) node & JA_TYPE_MASK);
1db4943c	228	assert(type < RCU_JA_NR_TYPES);
d68c6810 MD	229	return type;
	230	}
	231
	232	static
	233	struct rcu_ja_node ja_node_ptr(struct rcu_ja_node_flag node)
	234	{
	235	return (struct rcu_ja_node *) (((unsigned long) node) \| JA_PTR_MASK);
	236	}
	237
	238	struct rcu_ja_node alloc_rcu_ja_node(struct rcu_ja_type ja_type)
e5227865	239	{
1db4943c	240	return calloc(1U << ja_type->order, sizeof(char));
e5227865 MD	241	}
	242
	243	void free_rcu_ja_node(struct rcu_ja_node *node)
	244	{
	245	free(node);
	246	}
	247
d68c6810 MD	248	#define __JA_ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
	249	#define JA_ALIGN(v, align) __JA_ALIGN_MASK(v, (typeof(v)) (align) - 1)
	250	#define __JA_FLOOR_MASK(v, mask) ((v) & ~(mask))
	251	#define JA_FLOOR(v, align) __JA_FLOOR_MASK(v, (typeof(v)) (align) - 1)
	252
	253	static
1db4943c	254	uint8_t align_ptr_size(uint8_t ptr)
d68c6810	255	{
1db4943c	256	return (uint8_t ) JA_ALIGN((unsigned long) ptr, sizeof(void ));
d68c6810 MD	257	}
	258
	259	static
	260	struct rcu_ja_node_flag ja_linear_node_get_nth(const struct rcu_ja_type type,
	261	struct rcu_ja_node *node,
	262	uint8_t n)
	263	{
	264	uint8_t nr_child;
	265	uint8_t *values;
1db4943c	266	struct rcu_ja_node_flag **pointers;
d68c6810 MD	267	struct rcu_ja_node_flag *ptr;
	268	unsigned int i;
	269
fd800776	270	assert(!type \|\| type->type_class == RCU_JA_LINEAR);
d68c6810	271
1db4943c	272	nr_child = node->u.data[0];
d68c6810	273	cmm_smp_rmb(); /* read nr_child before values */
fd800776 MD	274	assert(!type \|\| nr_child <= type->max_child);
fd800776 MD	275	assert(!type \|\| nr_child >= type->min_child);
d68c6810	276
1db4943c	277	values = &node->u.data[1];
d68c6810 MD	278	for (i = 0; i < nr_child; i++) {
	279	if (values[i] == n)
	280	break;
	281	}
	282	if (i >= nr_child)
	283	return NULL;
	284	cmm_smp_rmb(); /* read values before pointer */
1db4943c	285	pointers = (struct rcu_ja_node_flag **) align_ptr_size(&values[nr_child]);
d68c6810 MD	286	ptr = pointers[i];
	287	assert(ja_node_ptr(ptr) != NULL);
	288	return ptr;
	289	}
	290
d68c6810	291	static
fd800776	292	struct rcu_ja_node_flag ja_pool_node_get_nth(const struct rcu_ja_type type,
d68c6810 MD	293	struct rcu_ja_node *node,
	294	uint8_t n)
	295	{
fd800776	296	struct rcu_ja_node *linear;
d68c6810	297
fd800776 MD	298	assert(type->type_class == RCU_JA_POOL);
fd800776 MD	299	linear = (struct rcu_ja_node *)
1db4943c	300	&node->u.data[((unsigned long) n >> (CHAR_BIT - type->nr_pool_order)) << type->pool_size_order];
fd800776	301	return ja_linear_node_get_nth(NULL, linear, n);
d68c6810 MD	302	}
	303
	304	static
	305	struct rcu_ja_node_flag ja_pigeon_node_get_nth(const struct rcu_ja_type type,
	306	struct rcu_ja_node *node,
	307	uint8_t n)
	308	{
	309	assert(type->type_class == RCU_JA_PIGEON);
1db4943c	310	return ((struct rcu_ja_node_flag **) node->u.data)[n];
d68c6810 MD	311	}
	312
	313	/* ja_node_get_nth: get nth item from a node */
	314	static
	315	struct rcu_ja_node_flag ja_node_get_nth(struct rcu_ja_node_flag node_flag,
	316	uint8_t n)
	317	{
	318	unsigned int type_index;
	319	struct rcu_ja_node *node;
	320	const struct rcu_ja_type *type;
	321
	322	node_flag = rcu_dereference(node_flag);
	323	node = ja_node_ptr(node_flag);
	324	assert(node != NULL);
	325	type_index = ja_node_type(node_flag);
	326	type = &ja_types[type_index];
	327
	328	switch (type->type_class) {
	329	case RCU_JA_LINEAR:
	330	return ja_linear_node_get_nth(type, node, n);
fd800776 MD	331	case RCU_JA_POOL:
fd800776 MD	332	return ja_pool_node_get_nth(type, node, n);
d68c6810 MD	333	case RCU_JA_PIGEON:
	334	return ja_pigeon_node_get_nth(type, node, n);
	335	default:
	336	assert(0);
	337	return (void *) -1UL;
	338	}
	339	}
	340
	341	/*
	342	* ja_node_set_nth: set nth item within a node. asserts that it is not
	343	* there yet.
	344	*/
e5227865	345