[lttng-tools.git] / src / common / hashtable / rculfhash-internal.h

#ifndef _URCU_RCULFHASH_INTERNAL_H
#define _URCU_RCULFHASH_INTERNAL_H

/*
 * urcu/rculfhash-internal.h
 *
 * Internal header for Lock-Free RCU Hash Table
 *
 * Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
 * Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.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 "rculfhash.h"

#ifdef DEBUG
#define dbg_printf(fmt, args...)     printf("[debug rculfhash] " fmt, ## args)
#else
#define dbg_printf(fmt, args...)
#endif

#if (CAA_BITS_PER_LONG == 32)
#define MAX_TABLE_ORDER			32
#else
#define MAX_TABLE_ORDER			64
#endif

#define MAX_CHUNK_TABLE			(1UL << 10)

#ifndef min
#define min(a, b)	((a) < (b) ? (a) : (b))
#endif

#ifndef max
#define max(a, b)	((a) > (b) ? (a) : (b))
#endif

struct ht_items_count;

/*
 * cds_lfht: Top-level data structure representing a lock-free hash
 * table. Defined in the implementation file to make it be an opaque
 * cookie to users.
 *
 * The fields used in fast-paths are placed near the end of the
 * structure, because we need to have a variable-sized union to contain
 * the mm plugin fields, which are used in the fast path.
 */
struct cds_lfht {
	/* Initial configuration items */
	unsigned long max_nr_buckets;
	const struct cds_lfht_mm_type *mm;	/* memory management plugin */
	const struct rcu_flavor_struct *flavor;	/* RCU flavor */

	long count;			/* global approximate item count */

	/*
	 * We need to put the work threads offline (QSBR) when taking this
	 * mutex, because we use synchronize_rcu within this mutex critical
	 * section, which waits on read-side critical sections, and could
	 * therefore cause grace-period deadlock if we hold off RCU G.P.
	 * completion.
	 */
	pthread_mutex_t resize_mutex;	/* resize mutex: add/del mutex */
	pthread_attr_t *resize_attr;	/* Resize threads attributes */
	unsigned int in_progress_resize, in_progress_destroy;
	unsigned long resize_target;
	int resize_initiated;

	/*
	 * Variables needed for add and remove fast-paths.
	 */
	int flags;
	unsigned long min_alloc_buckets_order;
	unsigned long min_nr_alloc_buckets;
	struct ht_items_count *split_count;	/* split item count */

	/*
	 * Variables needed for the lookup, add and remove fast-paths.
	 */
	unsigned long size;	/* always a power of 2, shared (RCU) */
	/*
	 * bucket_at pointer is kept here to skip the extra level of
	 * dereference needed to get to "mm" (this is a fast-path).
	 */
	struct cds_lfht_node *(*bucket_at)(struct cds_lfht *ht,
			unsigned long index);
	/*
	 * Dynamic length "tbl_chunk" needs to be at the end of
	 * cds_lfht.
	 */
	union {
		/*
		 * Contains the per order-index-level bucket node table.
		 * The size of each bucket node table is half the number
		 * of hashes contained in this order (except for order 0).
		 * The minimum allocation buckets size parameter allows
		 * combining the bucket node arrays of the lowermost
		 * levels to improve cache locality for small index orders.
		 */
		struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];

		/*
		 * Contains the bucket node chunks. The size of each
		 * bucket node chunk is ->min_alloc_size (we avoid to
		 * allocate chunks with different size). Chunks improve
		 * cache locality for small index orders, and are more
		 * friendly with environments where allocation of large
		 * contiguous memory areas is challenging due to memory
		 * fragmentation concerns or inability to use virtual
		 * memory addressing.
		 */
		struct cds_lfht_node *tbl_chunk[0];

		/*
		 * Memory mapping with room for all possible buckets.
		 * Their memory is allocated when needed.
		 */
		struct cds_lfht_node *tbl_mmap;
	};
	/*
	 * End of variables needed for the lookup, add and remove
	 * fast-paths.
	 */
};

extern unsigned int cds_lfht_fls_ulong(unsigned long x);
extern int cds_lfht_get_count_order_ulong(unsigned long x);

#ifdef POISON_FREE
#define poison_free(ptr)					\
	do {							\
		if (ptr) {					\
			memset(ptr, 0x42, sizeof(*(ptr)));	\
			free(ptr);				\
		}						\
	} while (0)
#else
#define poison_free(ptr)	free(ptr)
#endif

static inline
struct cds_lfht *__default_alloc_cds_lfht(
		const struct cds_lfht_mm_type *mm,
		unsigned long cds_lfht_size,
		unsigned long min_nr_alloc_buckets,
		unsigned long max_nr_buckets)
{
	struct cds_lfht *ht;

	ht = calloc(1, cds_lfht_size);
	assert(ht);

	ht->mm = mm;
	ht->bucket_at = mm->bucket_at;
	ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
	ht->min_alloc_buckets_order =
		cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
	ht->max_nr_buckets = max_nr_buckets;

	return ht;
}

#endif /* _URCU_RCULFHASH_INTERNAL_H */
Commit	Line	Data
bec39940 DG	1	#ifndef _URCU_RCULFHASH_INTERNAL_H
	2	#define _URCU_RCULFHASH_INTERNAL_H
	3
	4	/*
	5	* urcu/rculfhash-internal.h
	6	*
	7	* Internal header for Lock-Free RCU Hash Table
	8	*
	9	* Copyright 2011 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
	10	* Copyright 2011 - Lai Jiangshan <laijs@cn.fujitsu.com>
	11	*
	12	* This library is free software; you can redistribute it and/or
	13	* modify it under the terms of the GNU Lesser General Public
	14	* License as published by the Free Software Foundation; either
	15	* version 2.1 of the License, or (at your option) any later version.
	16	*
	17	* This library is distributed in the hope that it will be useful,
	18	* but WITHOUT ANY WARRANTY; without even the implied warranty of
	19	* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
	20	* Lesser General Public License for more details.
	21	*
	22	* You should have received a copy of the GNU Lesser General Public
	23	* License along with this library; if not, write to the Free Software
	24	* Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA
	25	*/
	26
	27	#include "rculfhash.h"
	28
	29	#ifdef DEBUG
	30	#define dbg_printf(fmt, args...) printf("[debug rculfhash] " fmt, ## args)
	31	#else
	32	#define dbg_printf(fmt, args...)
	33	#endif
	34
	35	#if (CAA_BITS_PER_LONG == 32)
	36	#define MAX_TABLE_ORDER 32
	37	#else
	38	#define MAX_TABLE_ORDER 64
	39	#endif
	40
	41	#define MAX_CHUNK_TABLE (1UL << 10)
	42
	43	#ifndef min
	44	#define min(a, b) ((a) < (b) ? (a) : (b))
	45	#endif
	46
	47	#ifndef max
	48	#define max(a, b) ((a) > (b) ? (a) : (b))
	49	#endif
	50
	51	struct ht_items_count;
	52
	53	/*
	54	* cds_lfht: Top-level data structure representing a lock-free hash
	55	* table. Defined in the implementation file to make it be an opaque
	56	* cookie to users.
	57	*
	58	* The fields used in fast-paths are placed near the end of the
	59	* structure, because we need to have a variable-sized union to contain
	60	* the mm plugin fields, which are used in the fast path.
	61	*/
	62	struct cds_lfht {
	63	/* Initial configuration items */
	64	unsigned long max_nr_buckets;
65	const struct cds_lfht_mm_type mm; / memory management plugin */
66	const struct rcu_flavor_struct flavor; / RCU flavor */
67
68	long count; /* global approximate item count */
69
70	/*
71	* We need to put the work threads offline (QSBR) when taking this
72	* mutex, because we use synchronize_rcu within this mutex critical
73	* section, which waits on read-side critical sections, and could
74	* therefore cause grace-period deadlock if we hold off RCU G.P.
75	* completion.
76	*/
77	pthread_mutex_t resize_mutex; /* resize mutex: add/del mutex */
78	pthread_attr_t resize_attr; / Resize threads attributes */
79	unsigned int in_progress_resize, in_progress_destroy;
80	unsigned long resize_target;
81	int resize_initiated;
82
83	/*
84	* Variables needed for add and remove fast-paths.
85	*/
86	int flags;
87	unsigned long min_alloc_buckets_order;
88	unsigned long min_nr_alloc_buckets;
89	struct ht_items_count split_count; / split item count */
90
91	/*
92	* Variables needed for the lookup, add and remove fast-paths.
93	*/
94	unsigned long size; /* always a power of 2, shared (RCU) */
95	/*
96	* bucket_at pointer is kept here to skip the extra level of
97	* dereference needed to get to "mm" (this is a fast-path).
98	*/
99	struct cds_lfht_node (bucket_at)(struct cds_lfht *ht,
100	unsigned long index);
101	/*
102	* Dynamic length "tbl_chunk" needs to be at the end of
103	* cds_lfht.
104	*/
105	union {
106	/*
107	* Contains the per order-index-level bucket node table.
108	* The size of each bucket node table is half the number
109	* of hashes contained in this order (except for order 0).
110	* The minimum allocation buckets size parameter allows
111	* combining the bucket node arrays of the lowermost
112	* levels to improve cache locality for small index orders.
113	*/
114	struct cds_lfht_node *tbl_order[MAX_TABLE_ORDER];
115
116	/*
117	* Contains the bucket node chunks. The size of each
118	* bucket node chunk is ->min_alloc_size (we avoid to
119	* allocate chunks with different size). Chunks improve
120	* cache locality for small index orders, and are more
121	* friendly with environments where allocation of large
122	* contiguous memory areas is challenging due to memory
123	* fragmentation concerns or inability to use virtual
124	* memory addressing.
125	*/
126	struct cds_lfht_node *tbl_chunk[0];
127
128	/*
129	* Memory mapping with room for all possible buckets.
130	* Their memory is allocated when needed.
131	*/
132	struct cds_lfht_node *tbl_mmap;
133	};
134	/*
135	* End of variables needed for the lookup, add and remove
136	* fast-paths.
137	*/
138	};
139
140	extern unsigned int cds_lfht_fls_ulong(unsigned long x);
141	extern int cds_lfht_get_count_order_ulong(unsigned long x);
142
143	#ifdef POISON_FREE
144	#define poison_free(ptr) \
145	do { \
146	if (ptr) { \
147	memset(ptr, 0x42, sizeof(*(ptr))); \
148	free(ptr); \
149	} \
150	} while (0)
151	#else
152	#define poison_free(ptr) free(ptr)
153	#endif
154
155	static inline
156	struct cds_lfht *__default_alloc_cds_lfht(
157	const struct cds_lfht_mm_type *mm,
158	unsigned long cds_lfht_size,
159	unsigned long min_nr_alloc_buckets,
160	unsigned long max_nr_buckets)
161	{
162	struct cds_lfht *ht;
163
164	ht = calloc(1, cds_lfht_size);
165	assert(ht);
166
167	ht->mm = mm;
168	ht->bucket_at = mm->bucket_at;
169	ht->min_nr_alloc_buckets = min_nr_alloc_buckets;
170	ht->min_alloc_buckets_order =
171	cds_lfht_get_count_order_ulong(min_nr_alloc_buckets);
172	ht->max_nr_buckets = max_nr_buckets;
173
174	return ht;
175	}
176
177	#endif /* _URCU_RCULFHASH_INTERNAL_H */