4 * Userspace RCU library - RCU Judy Array
6 * Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
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.
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.
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
28 #include <urcu/rcuja.h>
29 #include <urcu/compiler.h>
30 #include <urcu/arch.h>
32 #include <urcu-pointer.h>
33 #include <urcu/uatomic.h>
36 #include "rcuja-internal.h"
40 #define abs_int(a) ((int) (a) > 0 ? (int) (a) : -((int) (a)))
43 enum cds_ja_type_class
{
44 RCU_JA_LINEAR
= 0, /* Type A */
45 /* 32-bit: 1 to 25 children, 8 to 128 bytes */
46 /* 64-bit: 1 to 28 children, 16 to 256 bytes */
47 RCU_JA_POOL
= 1, /* Type B */
48 /* 32-bit: 26 to 100 children, 256 to 512 bytes */
49 /* 64-bit: 29 to 112 children, 512 to 1024 bytes */
50 RCU_JA_PIGEON
= 2, /* Type C */
51 /* 32-bit: 101 to 256 children, 1024 bytes */
52 /* 64-bit: 113 to 256 children, 2048 bytes */
53 /* Leaf nodes are implicit from their height in the tree */
56 RCU_JA_NULL
, /* not an encoded type, but keeps code regular */
60 enum cds_ja_type_class type_class
;
61 uint16_t min_child
; /* minimum number of children: 1 to 256 */
62 uint16_t max_child
; /* maximum number of children: 1 to 256 */
63 uint16_t max_linear_child
; /* per-pool max nr. children: 1 to 256 */
64 uint16_t order
; /* node size is (1 << order), in bytes */
65 uint16_t nr_pool_order
; /* number of pools */
66 uint16_t pool_size_order
; /* pool size */
70 * Iteration on the array to find the right node size for the number of
71 * children stops when it reaches .max_child == 256 (this is the largest
72 * possible node size, which contains 256 children).
73 * The min_child overlaps with the previous max_child to provide an
74 * hysteresis loop to reallocation for patterns of cyclic add/removal
75 * within the same node.
76 * The node the index within the following arrays is represented on 3
77 * bits. It identifies the node type, min/max number of children, and
79 * The max_child values for the RCU_JA_POOL below result from
80 * statistical approximation: over million populations, the max_child
81 * covers between 97% and 99% of the populations generated. Therefore, a
82 * fallback should exist to cover the rare extreme population unbalance
83 * cases, but it will not have a major impact on speed nor space
84 * consumption, since those are rare cases.
87 #if (CAA_BITS_PER_LONG < 64)
90 ja_type_0_max_child
= 1,
91 ja_type_1_max_child
= 3,
92 ja_type_2_max_child
= 6,
93 ja_type_3_max_child
= 12,
94 ja_type_4_max_child
= 25,
95 ja_type_5_max_child
= 48,
96 ja_type_6_max_child
= 92,
97 ja_type_7_max_child
= 256,
98 ja_type_8_max_child
= 0, /* NULL */
102 ja_type_0_max_linear_child
= 1,
103 ja_type_1_max_linear_child
= 3,
104 ja_type_2_max_linear_child
= 6,
105 ja_type_3_max_linear_child
= 12,
106 ja_type_4_max_linear_child
= 25,
107 ja_type_5_max_linear_child
= 24,
108 ja_type_6_max_linear_child
= 23,
112 ja_type_5_nr_pool_order
= 1,
113 ja_type_6_nr_pool_order
= 2,
116 const struct cds_ja_type ja_types
[] = {
117 { .type_class
= RCU_JA_LINEAR
, .min_child
= 1, .max_child
= ja_type_0_max_child
, .max_linear_child
= ja_type_0_max_linear_child
, .order
= 3, },
118 { .type_class
= RCU_JA_LINEAR
, .min_child
= 1, .max_child
= ja_type_1_max_child
, .max_linear_child
= ja_type_1_max_linear_child
, .order
= 4, },
119 { .type_class
= RCU_JA_LINEAR
, .min_child
= 3, .max_child
= ja_type_2_max_child
, .max_linear_child
= ja_type_2_max_linear_child
, .order
= 5, },
120 { .type_class
= RCU_JA_LINEAR
, .min_child
= 4, .max_child
= ja_type_3_max_child
, .max_linear_child
= ja_type_3_max_linear_child
, .order
= 6, },
121 { .type_class
= RCU_JA_LINEAR
, .min_child
= 10, .max_child
= ja_type_4_max_child
, .max_linear_child
= ja_type_4_max_linear_child
, .order
= 7, },
123 /* Pools may fill sooner than max_child */
124 { .type_class
= RCU_JA_POOL
, .min_child
= 20, .max_child
= ja_type_5_max_child
, .max_linear_child
= ja_type_5_max_linear_child
, .order
= 8, .nr_pool_order
= ja_type_5_nr_pool_order
, .pool_size_order
= 7, },
125 { .type_class
= RCU_JA_POOL
, .min_child
= 45, .max_child
= ja_type_6_max_child
, .max_linear_child
= ja_type_6_max_linear_child
, .order
= 9, .nr_pool_order
= ja_type_6_nr_pool_order
, .pool_size_order
= 7, },
128 * Upon node removal below min_child, if child pool is filled
129 * beyond capacity, we roll back to pigeon.
131 { .type_class
= RCU_JA_PIGEON
, .min_child
= 89, .max_child
= ja_type_7_max_child
, .order
= 10, },
133 { .type_class
= RCU_JA_NULL
, .min_child
= 0, .max_child
= ja_type_8_max_child
, },
135 #else /* !(CAA_BITS_PER_LONG < 64) */
136 /* 64-bit pointers */
138 ja_type_0_max_child
= 1,
139 ja_type_1_max_child
= 3,
140 ja_type_2_max_child
= 7,
141 ja_type_3_max_child
= 14,
142 ja_type_4_max_child
= 28,
143 ja_type_5_max_child
= 54,
144 ja_type_6_max_child
= 104,
145 ja_type_7_max_child
= 256,
146 ja_type_8_max_child
= 256,
150 ja_type_0_max_linear_child
= 1,
151 ja_type_1_max_linear_child
= 3,
152 ja_type_2_max_linear_child
= 7,
153 ja_type_3_max_linear_child
= 14,
154 ja_type_4_max_linear_child
= 28,
155 ja_type_5_max_linear_child
= 27,
156 ja_type_6_max_linear_child
= 26,
160 ja_type_5_nr_pool_order
= 1,
161 ja_type_6_nr_pool_order
= 2,
164 const struct cds_ja_type ja_types
[] = {
165 { .type_class
= RCU_JA_LINEAR
, .min_child
= 1, .max_child
= ja_type_0_max_child
, .max_linear_child
= ja_type_0_max_linear_child
, .order
= 4, },
166 { .type_class
= RCU_JA_LINEAR
, .min_child
= 1, .max_child
= ja_type_1_max_child
, .max_linear_child
= ja_type_1_max_linear_child
, .order
= 5, },
167 { .type_class
= RCU_JA_LINEAR
, .min_child
= 3, .max_child
= ja_type_2_max_child
, .max_linear_child
= ja_type_2_max_linear_child
, .order
= 6, },
168 { .type_class
= RCU_JA_LINEAR
, .min_child
= 5, .max_child
= ja_type_3_max_child
, .max_linear_child
= ja_type_3_max_linear_child
, .order
= 7, },
169 { .type_class
= RCU_JA_LINEAR
, .min_child
= 10, .max_child
= ja_type_4_max_child
, .max_linear_child
= ja_type_4_max_linear_child
, .order
= 8, },
171 /* Pools may fill sooner than max_child. */
172 { .type_class
= RCU_JA_POOL
, .min_child
= 22, .max_child
= ja_type_5_max_child
, .max_linear_child
= ja_type_5_max_linear_child
, .order
= 9, .nr_pool_order
= ja_type_5_nr_pool_order
, .pool_size_order
= 8, },
173 { .type_class
= RCU_JA_POOL
, .min_child
= 51, .max_child
= ja_type_6_max_child
, .max_linear_child
= ja_type_6_max_linear_child
, .order
= 10, .nr_pool_order
= ja_type_6_nr_pool_order
, .pool_size_order
= 8, },
176 * Upon node removal below min_child, if child pool is filled
177 * beyond capacity, we roll back to pigeon.
179 { .type_class
= RCU_JA_PIGEON
, .min_child
= 101, .max_child
= ja_type_7_max_child
, .order
= 11, },
181 { .type_class
= RCU_JA_NULL
, .min_child
= 0, .max_child
= ja_type_8_max_child
, },
183 #endif /* !(BITS_PER_LONG < 64) */
185 static inline __attribute__((unused
))
186 void static_array_size_check(void)
188 CAA_BUILD_BUG_ON(CAA_ARRAY_SIZE(ja_types
) < JA_TYPE_MAX_NR
);
192 * The cds_ja_node contains the compressed node data needed for
193 * read-side. For linear and pool node configurations, it starts with a
194 * byte counting the number of children in the node. Then, the
195 * node-specific data is placed.
196 * The node mutex, if any is needed, protecting concurrent updated of
197 * each node is placed in a separate hash table indexed by node address.
198 * For the pigeon configuration, the number of children is also kept in
199 * a separate hash table, indexed by node address, because it is only
200 * required for updates.
203 #define DECLARE_LINEAR_NODE(index) \
206 uint8_t child_value[ja_type_## index ##_max_linear_child]; \
207 struct cds_ja_inode_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
210 #define DECLARE_POOL_NODE(index) \
214 uint8_t child_value[ja_type_## index ##_max_linear_child]; \
215 struct cds_ja_inode_flag *child_ptr[ja_type_## index ##_max_linear_child]; \
216 } linear[1U << ja_type_## index ##_nr_pool_order]; \
219 struct cds_ja_inode
{
221 /* Linear configuration */
222 DECLARE_LINEAR_NODE(0) conf_0
;
223 DECLARE_LINEAR_NODE(1) conf_1
;
224 DECLARE_LINEAR_NODE(2) conf_2
;
225 DECLARE_LINEAR_NODE(3) conf_3
;
226 DECLARE_LINEAR_NODE(4) conf_4
;
228 /* Pool configuration */
229 DECLARE_POOL_NODE(5) conf_5
;
230 DECLARE_POOL_NODE(6) conf_6
;
232 /* Pigeon configuration */
234 struct cds_ja_inode_flag
*child
[ja_type_7_max_child
];
236 /* data aliasing nodes for computed accesses */
237 uint8_t data
[sizeof(struct cds_ja_inode_flag
*) * ja_type_7_max_child
];
242 JA_RECOMPACT_ADD_SAME
,
243 JA_RECOMPACT_ADD_NEXT
,
248 unsigned long node_fallback_count_distribution
[JA_ENTRY_PER_NODE
];
251 struct cds_ja_inode
*_ja_node_mask_ptr(struct cds_ja_inode_flag
*node
)
253 return (struct cds_ja_inode
*) (((unsigned long) node
) & JA_PTR_MASK
);
256 unsigned long ja_node_type(struct cds_ja_inode_flag
*node
)
260 if (_ja_node_mask_ptr(node
) == NULL
) {
261 return NODE_INDEX_NULL
;
263 type
= (unsigned int) ((unsigned long) node
& JA_TYPE_MASK
);
264 assert(type
< (1UL << JA_TYPE_BITS
));
268 struct cds_ja_inode
*ja_node_ptr(struct cds_ja_inode_flag
*node
)
270 unsigned long type_index
= ja_node_type(node
);
271 const struct cds_ja_type
*type
;
273 type
= &ja_types
[type_index
];
274 switch (type
->type_class
) {
276 case RCU_JA_PIGEON
: /* fall-through */
277 case RCU_JA_NULL
: /* fall-through */
278 default: /* fall-through */
279 return _ja_node_mask_ptr(node
);
281 switch (type
->nr_pool_order
) {
283 return (struct cds_ja_inode
*) (((unsigned long) node
) & ~(JA_POOL_1D_MASK
| JA_TYPE_MASK
));
285 return (struct cds_ja_inode
*) (((unsigned long) node
) & ~(JA_POOL_2D_MASK
| JA_POOL_1D_MASK
| JA_TYPE_MASK
));
292 struct cds_ja_inode
*alloc_cds_ja_node(const struct cds_ja_type
*ja_type
)
294 size_t len
= 1U << ja_type
->order
;
298 ret
= posix_memalign(&p
, len
, len
);
306 void free_cds_ja_node(struct cds_ja_inode
*node
)
311 #define __JA_ALIGN_MASK(v, mask) (((v) + (mask)) & ~(mask))
312 #define JA_ALIGN(v, align) __JA_ALIGN_MASK(v, (typeof(v)) (align) - 1)
313 #define __JA_FLOOR_MASK(v, mask) ((v) & ~(mask))
314 #define JA_FLOOR(v, align) __JA_FLOOR_MASK(v, (typeof(v)) (align) - 1)
317 uint8_t *align_ptr_size(uint8_t *ptr
)
319 return (uint8_t *) JA_ALIGN((unsigned long) ptr
, sizeof(void *));
323 uint8_t ja_linear_node_get_nr_child(const struct cds_ja_type
*type
,
324 struct cds_ja_inode
*node
)
326 assert(type
->type_class
== RCU_JA_LINEAR
|| type
->type_class
== RCU_JA_POOL
);
327 return rcu_dereference(node
->u
.data
[0]);
331 * The order in which values and pointers are does does not matter: if
332 * a value is missing, we return NULL. If a value is there, but its
333 * associated pointers is still NULL, we return NULL too.
336 struct cds_ja_inode_flag
*ja_linear_node_get_nth(const struct cds_ja_type
*type
,
337 struct cds_ja_inode
*node
,
338 struct cds_ja_inode_flag
***child_node_flag_ptr
,
339 struct cds_ja_inode_flag
**child_node_flag_v
,
340 struct cds_ja_inode_flag
***node_flag_ptr
,
345 struct cds_ja_inode_flag
**pointers
;
346 struct cds_ja_inode_flag
*ptr
;
349 assert(type
->type_class
== RCU_JA_LINEAR
|| type
->type_class
== RCU_JA_POOL
);
351 nr_child
= ja_linear_node_get_nr_child(type
, node
);
352 cmm_smp_rmb(); /* read nr_child before values and pointers */
353 assert(nr_child
<= type
->max_linear_child
);
354 assert(type
->type_class
!= RCU_JA_LINEAR
|| nr_child
>= type
->min_child
);
356 values
= &node
->u
.data
[1];
357 for (i
= 0; i
< nr_child
; i
++) {
358 if (CMM_LOAD_SHARED(values
[i
]) == n
)
362 if (caa_unlikely(node_flag_ptr
))
363 *node_flag_ptr
= NULL
;
366 pointers
= (struct cds_ja_inode_flag
**) align_ptr_size(&values
[type
->max_linear_child
]);
367 ptr
= rcu_dereference(pointers
[i
]);
368 if (caa_unlikely(child_node_flag_ptr
) && ptr
)
369 *child_node_flag_ptr
= &pointers
[i
];
370 if (caa_unlikely(child_node_flag_v
) && ptr
)
371 *child_node_flag_v
= ptr
;
372 if (caa_unlikely(node_flag_ptr
))
373 *node_flag_ptr
= &pointers
[i
];
378 void ja_linear_node_get_ith_pos(const struct cds_ja_type
*type
,
379 struct cds_ja_inode
*node
,
382 struct cds_ja_inode_flag
**iter
)
385 struct cds_ja_inode_flag
**pointers
;
387 assert(type
->type_class
== RCU_JA_LINEAR
|| type
->type_class
== RCU_JA_POOL
);
388 assert(i
< ja_linear_node_get_nr_child(type
, node
));
390 values
= &node
->u
.data
[1];
392 pointers
= (struct cds_ja_inode_flag
**) align_ptr_size(&values
[type
->max_linear_child
]);
397 struct cds_ja_inode_flag
*ja_pool_node_get_nth(const struct cds_ja_type
*type
,
398 struct cds_ja_inode
*node
,
399 struct cds_ja_inode_flag
*node_flag
,
400 struct cds_ja_inode_flag
***child_node_flag_ptr
,
401 struct cds_ja_inode_flag
**child_node_flag_v
,
402 struct cds_ja_inode_flag
***node_flag_ptr
,
405 struct cds_ja_inode
*linear
;
407 assert(type
->type_class
== RCU_JA_POOL
);
409 switch (type
->nr_pool_order
) {
412 unsigned long bitsel
, index
;
414 bitsel
= ja_node_pool_1d_bitsel(node_flag
);
415 assert(bitsel
< CHAR_BIT
);
416 index
= ((unsigned long) n
>> bitsel
) & 0x1;
417 linear
= (struct cds_ja_inode
*) &node
->u
.data
[index
<< type
->pool_size_order
];
422 unsigned long bitsel
[2], index
[2], rindex
;
424 ja_node_pool_2d_bitsel(node_flag
, bitsel
);
425 assert(bitsel
[0] < CHAR_BIT
);
426 assert(bitsel
[1] < CHAR_BIT
);
427 index
[0] = ((unsigned long) n
>> bitsel
[0]) & 0x1;
429 index
[1] = ((unsigned long) n
>> bitsel
[1]) & 0x1;
430 rindex
= index
[0] | index
[1];
431 linear
= (struct cds_ja_inode
*) &node
->u
.data
[rindex
<< type
->pool_size_order
];
438 return ja_linear_node_get_nth(type
, linear
, child_node_flag_ptr
,
439 child_node_flag_v
, node_flag_ptr
, n
);
443 struct cds_ja_inode
*ja_pool_node_get_ith_pool(const struct cds_ja_type
*type
,
444 struct cds_ja_inode
*node
,
447 assert(type
->type_class
== RCU_JA_POOL
);
448 return (struct cds_ja_inode
*)
449 &node
->u
.data
[(unsigned int) i
<< type
->pool_size_order
];
453 struct cds_ja_inode_flag
*ja_pigeon_node_get_nth(const struct cds_ja_type
*type
,
454 struct cds_ja_inode
*node
,
455 struct cds_ja_inode_flag
***child_node_flag_ptr
,
456 struct cds_ja_inode_flag
**child_node_flag_v
,
457 struct cds_ja_inode_flag
***node_flag_ptr
,
460 struct cds_ja_inode_flag
**child_node_flag
;
461 struct cds_ja_inode_flag
*child_node_flag_read
;
463 assert(type
->type_class
== RCU_JA_PIGEON
);
464 child_node_flag
= &((struct cds_ja_inode_flag
**) node
->u
.data
)[n
];
465 child_node_flag_read
= rcu_dereference(*child_node_flag
);
466 dbg_printf("ja_pigeon_node_get_nth child_node_flag_ptr %p\n",
468 if (caa_unlikely(child_node_flag_ptr
) && child_node_flag_read
)
469 *child_node_flag_ptr
= child_node_flag
;
470 if (caa_unlikely(child_node_flag_v
) && child_node_flag_read
)
471 *child_node_flag_v
= child_node_flag_read
;
472 if (caa_unlikely(node_flag_ptr
))
473 *node_flag_ptr
= child_node_flag
;
474 return child_node_flag_read
;
478 struct cds_ja_inode_flag
*ja_pigeon_node_get_ith_pos(const struct cds_ja_type
*type
,
479 struct cds_ja_inode
*node
,
482 return ja_pigeon_node_get_nth(type
, node
, NULL
, NULL
, NULL
, i
);
486 * ja_node_get_nth: get nth item from a node.
487 * node_flag is already rcu_dereference'd.
490 struct cds_ja_inode_flag
*ja_node_get_nth(struct cds_ja_inode_flag
*node_flag
,
491 struct cds_ja_inode_flag
***child_node_flag_ptr
,
492 struct cds_ja_inode_flag
**child_node_flag
,
493 struct cds_ja_inode_flag
***node_flag_ptr
,
496 unsigned int type_index
;
497 struct cds_ja_inode
*node
;
498 const struct cds_ja_type
*type
;
500 node
= ja_node_ptr(node_flag
);
501 assert(node
!= NULL
);
502 type_index
= ja_node_type(node_flag
);
503 type
= &ja_types
[type_index
];
505 switch (type
->type_class
) {
507 return ja_linear_node_get_nth(type
, node
,
508 child_node_flag_ptr
, child_node_flag
,
511 return ja_pool_node_get_nth(type
, node
, node_flag
,
512 child_node_flag_ptr
, child_node_flag
,
515 return ja_pigeon_node_get_nth(type
, node
,
516 child_node_flag_ptr
, child_node_flag
,
520 return (void *) -1UL;
525 int ja_linear_node_set_nth(const struct cds_ja_type
*type
,
526 struct cds_ja_inode
*node
,
527 struct cds_ja_shadow_node
*shadow_node
,
529 struct cds_ja_inode_flag
*child_node_flag
)
532 uint8_t *values
, *nr_child_ptr
;
533 struct cds_ja_inode_flag
**pointers
;
534 unsigned int i
, unused
= 0;
536 assert(type
->type_class
== RCU_JA_LINEAR
|| type
->type_class
== RCU_JA_POOL
);
538 nr_child_ptr
= &node
->u
.data
[0];
539 dbg_printf("linear set nth: nr_child_ptr %p\n", nr_child_ptr
);
540 nr_child
= *nr_child_ptr
;
541 assert(nr_child
<= type
->max_linear_child
);
543 values
= &node
->u
.data
[1];
544 pointers
= (struct cds_ja_inode_flag
**) align_ptr_size(&values
[type
->max_linear_child
]);
545 /* Check if node value is already populated */
546 for (i
= 0; i
< nr_child
; i
++) {
547 if (values
[i
] == n
) {
557 if (i
== nr_child
&& nr_child
>= type
->max_linear_child
) {
559 return -ERANGE
; /* recompact node */
561 return -ENOSPC
; /* No space left in this node type */
564 assert(pointers
[i
] == NULL
);
565 rcu_assign_pointer(pointers
[i
], child_node_flag
);
566 /* If we expanded the nr_child, increment it */
568 CMM_STORE_SHARED(values
[nr_child
], n
);
569 /* write pointer and value before nr_child */
571 CMM_STORE_SHARED(*nr_child_ptr
, nr_child
+ 1);
573 shadow_node
->nr_child
++;
574 dbg_printf("linear set nth: %u child, shadow: %u child, for node %p shadow %p\n",
575 (unsigned int) CMM_LOAD_SHARED(*nr_child_ptr
),
576 (unsigned int) shadow_node
->nr_child
,
583 int ja_pool_node_set_nth(const struct cds_ja_type
*type
,
584 struct cds_ja_inode
*node
,
585 struct cds_ja_inode_flag
*node_flag
,
586 struct cds_ja_shadow_node
*shadow_node
,
588 struct cds_ja_inode_flag
*child_node_flag
)
590 struct cds_ja_inode
*linear
;
592 assert(type
->type_class
== RCU_JA_POOL
);
594 switch (type
->nr_pool_order
) {
597 unsigned long bitsel
, index
;
599 bitsel
= ja_node_pool_1d_bitsel(node_flag
);
600 assert(bitsel
< CHAR_BIT
);
601 index
= ((unsigned long) n
>> bitsel
) & 0x1;
602 linear
= (struct cds_ja_inode
*) &node
->u
.data
[index
<< type
->pool_size_order
];
607 unsigned long bitsel
[2], index
[2], rindex
;
609 ja_node_pool_2d_bitsel(node_flag
, bitsel
);
610 assert(bitsel
[0] < CHAR_BIT
);
611 assert(bitsel
[1] < CHAR_BIT
);
612 index
[0] = ((unsigned long) n
>> bitsel
[0]) & 0x1;
614 index
[1] = ((unsigned long) n
>> bitsel
[1]) & 0x1;
615 rindex
= index
[0] | index
[1];
616 linear
= (struct cds_ja_inode
*) &node
->u
.data
[rindex
<< type
->pool_size_order
];
624 return ja_linear_node_set_nth(type
, linear
, shadow_node
,
629 int ja_pigeon_node_set_nth(const struct cds_ja_type
*type
,
630 struct cds_ja_inode
*node
,
631 struct cds_ja_shadow_node
*shadow_node
,
633 struct cds_ja_inode_flag
*child_node_flag
)
635 struct cds_ja_inode_flag
**ptr
;
637 assert(type
->type_class
== RCU_JA_PIGEON
);
638 ptr
= &((struct cds_ja_inode_flag
**) node
->u
.data
)[n
];
641 rcu_assign_pointer(*ptr
, child_node_flag
);
642 shadow_node
->nr_child
++;
647 * _ja_node_set_nth: set nth item within a node. Return an error
648 * (negative error value) if it is already there.
651 int _ja_node_set_nth(const struct cds_ja_type
*type
,
652 struct cds_ja_inode
*node
,
653 struct cds_ja_inode_flag
*node_flag
,
654 struct cds_ja_shadow_node
*shadow_node
,
656 struct cds_ja_inode_flag
*child_node_flag
)
658 switch (type
->type_class
) {
660 return ja_linear_node_set_nth(type
, node
, shadow_node
, n
,
663 return ja_pool_node_set_nth(type
, node
, node_flag
, shadow_node
, n
,
666 return ja_pigeon_node_set_nth(type
, node
, shadow_node
, n
,
679 int ja_linear_node_clear_ptr(const struct cds_ja_type
*type
,
680 struct cds_ja_inode
*node
,
681 struct cds_ja_shadow_node
*shadow_node
,
682 struct cds_ja_inode_flag
**node_flag_ptr
)
685 uint8_t *nr_child_ptr
;
687 assert(type
->type_class
== RCU_JA_LINEAR
|| type
->type_class
== RCU_JA_POOL
);
689 nr_child_ptr
= &node
->u
.data
[0];
690 nr_child
= *nr_child_ptr
;
691 assert(nr_child
<= type
->max_linear_child
);
693 if (shadow_node
->fallback_removal_count
) {
694 shadow_node
->fallback_removal_count
--;
696 if (type
->type_class
== RCU_JA_LINEAR
697 && shadow_node
->nr_child
<= type
->min_child
) {
698 /* We need to try recompacting the node */
702 dbg_printf("linear clear ptr: nr_child_ptr %p\n", nr_child_ptr
);
703 assert(*node_flag_ptr
!= NULL
);
704 rcu_assign_pointer(*node_flag_ptr
, NULL
);
706 * Value and nr_child are never changed (would cause ABA issue).
707 * Instead, we leave the pointer to NULL and recompact the node
708 * once in a while. It is allowed to set a NULL pointer to a new
709 * value without recompaction though.
710 * Only update the shadow node accounting.
712 shadow_node
->nr_child
--;
713 dbg_printf("linear clear ptr: %u child, shadow: %u child, for node %p shadow %p\n",
714 (unsigned int) CMM_LOAD_SHARED(*nr_child_ptr
),
715 (unsigned int) shadow_node
->nr_child
,
721 int ja_pool_node_clear_ptr(const struct cds_ja_type
*type
,
722 struct cds_ja_inode
*node
,
723 struct cds_ja_inode_flag
*node_flag
,
724 struct cds_ja_shadow_node
*shadow_node
,
725 struct cds_ja_inode_flag
**node_flag_ptr
,
728 struct cds_ja_inode
*linear
;
730 assert(type
->type_class
== RCU_JA_POOL
);
732 if (shadow_node
->fallback_removal_count
) {
733 shadow_node
->fallback_removal_count
--;
735 /* We should try recompacting the node */
736 if (shadow_node
->nr_child
<= type
->min_child
)
740 switch (type
->nr_pool_order
) {
743 unsigned long bitsel
, index
;
745 bitsel
= ja_node_pool_1d_bitsel(node_flag
);
746 assert(bitsel
< CHAR_BIT
);
747 index
= ((unsigned long) n
>> bitsel
) & type
->nr_pool_order
;
748 linear
= (struct cds_ja_inode
*) &node
->u
.data
[index
<< type
->pool_size_order
];
753 unsigned long bitsel
[2], index
[2], rindex
;
755 ja_node_pool_2d_bitsel(node_flag
, bitsel
);
756 assert(bitsel
[0] < CHAR_BIT
);
757 assert(bitsel
[1] < CHAR_BIT
);
758 index
[0] = ((unsigned long) n
>> bitsel
[0]) & 0x1;
760 index
[1] = ((unsigned long) n
>> bitsel
[1]) & 0x1;
761 rindex
= index
[0] | index
[1];
762 linear
= (struct cds_ja_inode
*) &node
->u
.data
[rindex
<< type
->pool_size_order
];
770 return ja_linear_node_clear_ptr(type
, linear
, shadow_node
, node_flag_ptr
);
774 int ja_pigeon_node_clear_ptr(const struct cds_ja_type
*type
,
775 struct cds_ja_inode
*node
,
776 struct cds_ja_shadow_node
*shadow_node
,
777 struct cds_ja_inode_flag
**node_flag_ptr
)
779 assert(type
->type_class
== RCU_JA_PIGEON
);
781 if (shadow_node
->fallback_removal_count
) {
782 shadow_node
->fallback_removal_count
--;
784 /* We should try recompacting the node */
785 if (shadow_node
->nr_child
<= type
->min_child
)
788 dbg_printf("ja_pigeon_node_clear_ptr: clearing ptr: %p\n", *node_flag_ptr
);
789 rcu_assign_pointer(*node_flag_ptr
, NULL
);
790 shadow_node
->nr_child
--;
795 * _ja_node_clear_ptr: clear ptr item within a node. Return an error
796 * (negative error value) if it is not found (-ENOENT).
799 int _ja_node_clear_ptr(const struct cds_ja_type
*type
,
800 struct cds_ja_inode
*node
,
801 struct cds_ja_inode_flag
*node_flag
,
802 struct cds_ja_shadow_node
*shadow_node
,
803 struct cds_ja_inode_flag
**node_flag_ptr
,
806 switch (type
->type_class
) {
808 return ja_linear_node_clear_ptr(type
, node
, shadow_node
, node_flag_ptr
);
810 return ja_pool_node_clear_ptr(type
, node
, node_flag
, shadow_node
, node_flag_ptr
, n
);
812 return ja_pigeon_node_clear_ptr(type
, node
, shadow_node
, node_flag_ptr
);
824 * Calculate bit distribution. Returns the bit (0 to 7) that splits the
825 * distribution in two sub-distributions containing as much elements one
826 * compared to the other.
829 unsigned int ja_node_sum_distribution_1d(enum ja_recompact mode
,
831 unsigned int type_index
,
832 const struct cds_ja_type
*type
,
833 struct cds_ja_inode
*node
,
834 struct cds_ja_shadow_node
*shadow_node
,
836 struct cds_ja_inode_flag
*child_node_flag
,
837 struct cds_ja_inode_flag
**nullify_node_flag_ptr
)
839 uint8_t nr_one
[JA_BITS_PER_BYTE
];
840 unsigned int bitsel
= 0, bit_i
, overall_best_distance
= UINT_MAX
;
841 unsigned int distrib_nr_child
= 0;
843 memset(nr_one
, 0, sizeof(nr_one
));
845 switch (type
->type_class
) {
849 ja_linear_node_get_nr_child(type
, node
);
852 for (i
= 0; i
< nr_child
; i
++) {
853 struct cds_ja_inode_flag
*iter
;
856 ja_linear_node_get_ith_pos(type
, node
, i
, &v
, &iter
);
859 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
861 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
862 if (v
& (1U << bit_i
))
871 unsigned int pool_nr
;
873 for (pool_nr
= 0; pool_nr
< (1U << type
->nr_pool_order
); pool_nr
++) {
874 struct cds_ja_inode
*pool
=
875 ja_pool_node_get_ith_pool(type
,
878 ja_linear_node_get_nr_child(type
, pool
);
881 for (j
= 0; j
< nr_child
; j
++) {
882 struct cds_ja_inode_flag
*iter
;
885 ja_linear_node_get_ith_pos(type
, pool
,
889 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
891 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
892 if (v
& (1U << bit_i
))
905 assert(mode
== JA_RECOMPACT_DEL
);
906 nr_child
= shadow_node
->nr_child
;
907 for (i
= 0; i
< nr_child
; i
++) {
908 struct cds_ja_inode_flag
*iter
;
910 iter
= ja_pigeon_node_get_ith_pos(type
, node
, i
);
913 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
915 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
916 if (i
& (1U << bit_i
))
924 assert(mode
== JA_RECOMPACT_ADD_NEXT
);
931 if (mode
== JA_RECOMPACT_ADD_NEXT
|| mode
== JA_RECOMPACT_ADD_SAME
) {
932 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
933 if (n
& (1U << bit_i
))
940 * The best bit selector is that for which the number of ones is
941 * closest to half of the number of children in the
942 * distribution. We calculate the distance using the double of
943 * the sub-distribution sizes to eliminate truncation error.
945 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
946 unsigned int distance_to_best
;
948 distance_to_best
= abs_int((nr_one
[bit_i
] << 1U) - distrib_nr_child
);
949 if (distance_to_best
< overall_best_distance
) {
950 overall_best_distance
= distance_to_best
;
954 dbg_printf("1 dimension pool bit selection: (%u)\n", bitsel
);
959 * Calculate bit distribution in two dimensions. Returns the two bits
960 * (each 0 to 7) that splits the distribution in four sub-distributions
961 * containing as much elements one compared to the other.
964 void ja_node_sum_distribution_2d(enum ja_recompact mode
,
966 unsigned int type_index
,
967 const struct cds_ja_type
*type
,
968 struct cds_ja_inode
*node
,
969 struct cds_ja_shadow_node
*shadow_node
,
971 struct cds_ja_inode_flag
*child_node_flag
,
972 struct cds_ja_inode_flag
**nullify_node_flag_ptr
,
973 unsigned int *_bitsel
)
975 uint8_t nr_2d_11
[JA_BITS_PER_BYTE
][JA_BITS_PER_BYTE
],
976 nr_2d_10
[JA_BITS_PER_BYTE
][JA_BITS_PER_BYTE
],
977 nr_2d_01
[JA_BITS_PER_BYTE
][JA_BITS_PER_BYTE
],
978 nr_2d_00
[JA_BITS_PER_BYTE
][JA_BITS_PER_BYTE
];
979 unsigned int bitsel
[2] = { 0, 1 };
980 unsigned int bit_i
, bit_j
;
981 int overall_best_distance
= INT_MAX
;
982 unsigned int distrib_nr_child
= 0;
984 memset(nr_2d_11
, 0, sizeof(nr_2d_11
));
985 memset(nr_2d_10
, 0, sizeof(nr_2d_10
));
986 memset(nr_2d_01
, 0, sizeof(nr_2d_01
));
987 memset(nr_2d_00
, 0, sizeof(nr_2d_00
));
989 switch (type
->type_class
) {
993 ja_linear_node_get_nr_child(type
, node
);
996 for (i
= 0; i
< nr_child
; i
++) {
997 struct cds_ja_inode_flag
*iter
;
1000 ja_linear_node_get_ith_pos(type
, node
, i
, &v
, &iter
);
1003 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1005 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1006 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1007 if ((v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1008 nr_2d_11
[bit_i
][bit_j
]++;
1010 if ((v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1011 nr_2d_10
[bit_i
][bit_j
]++;
1013 if (!(v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1014 nr_2d_01
[bit_i
][bit_j
]++;
1016 if (!(v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1017 nr_2d_00
[bit_i
][bit_j
]++;
1027 unsigned int pool_nr
;
1029 for (pool_nr
= 0; pool_nr
< (1U << type
->nr_pool_order
); pool_nr
++) {
1030 struct cds_ja_inode
*pool
=
1031 ja_pool_node_get_ith_pool(type
,
1034 ja_linear_node_get_nr_child(type
, pool
);
1037 for (j
= 0; j
< nr_child
; j
++) {
1038 struct cds_ja_inode_flag
*iter
;
1041 ja_linear_node_get_ith_pos(type
, pool
,
1045 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1047 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1048 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1049 if ((v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1050 nr_2d_11
[bit_i
][bit_j
]++;
1052 if ((v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1053 nr_2d_10
[bit_i
][bit_j
]++;
1055 if (!(v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1056 nr_2d_01
[bit_i
][bit_j
]++;
1058 if (!(v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1059 nr_2d_00
[bit_i
][bit_j
]++;
1073 assert(mode
== JA_RECOMPACT_DEL
);
1074 nr_child
= shadow_node
->nr_child
;
1075 for (i
= 0; i
< nr_child
; i
++) {
1076 struct cds_ja_inode_flag
*iter
;
1078 iter
= ja_pigeon_node_get_ith_pos(type
, node
, i
);
1081 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1083 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1084 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1085 if ((i
& (1U << bit_i
)) && (i
& (1U << bit_j
))) {
1086 nr_2d_11
[bit_i
][bit_j
]++;
1088 if ((i
& (1U << bit_i
)) && !(i
& (1U << bit_j
))) {
1089 nr_2d_10
[bit_i
][bit_j
]++;
1091 if (!(i
& (1U << bit_i
)) && (i
& (1U << bit_j
))) {
1092 nr_2d_01
[bit_i
][bit_j
]++;
1094 if (!(i
& (1U << bit_i
)) && !(i
& (1U << bit_j
))) {
1095 nr_2d_00
[bit_i
][bit_j
]++;
1104 assert(mode
== JA_RECOMPACT_ADD_NEXT
);
1111 if (mode
== JA_RECOMPACT_ADD_NEXT
|| mode
== JA_RECOMPACT_ADD_SAME
) {
1112 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1113 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1114 if ((n
& (1U << bit_i
)) && (n
& (1U << bit_j
))) {
1115 nr_2d_11
[bit_i
][bit_j
]++;
1117 if ((n
& (1U << bit_i
)) && !(n
& (1U << bit_j
))) {
1118 nr_2d_10
[bit_i
][bit_j
]++;
1120 if (!(n
& (1U << bit_i
)) && (n
& (1U << bit_j
))) {
1121 nr_2d_01
[bit_i
][bit_j
]++;
1123 if (!(n
& (1U << bit_i
)) && !(n
& (1U << bit_j
))) {
1124 nr_2d_00
[bit_i
][bit_j
]++;
1132 * The best bit selector is that for which the number of nodes
1133 * in each sub-class is closest to one-fourth of the number of
1134 * children in the distribution. We calculate the distance using
1135 * 4 times the size of the sub-distribution to eliminate
1138 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1139 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1140 int distance_to_best
[4];
1142 distance_to_best
[0] = (nr_2d_11
[bit_i
][bit_j
] << 2U) - distrib_nr_child
;
1143 distance_to_best
[1] = (nr_2d_10
[bit_i
][bit_j
] << 2U) - distrib_nr_child
;
1144 distance_to_best
[2] = (nr_2d_01
[bit_i
][bit_j
] << 2U) - distrib_nr_child
;
1145 distance_to_best
[3] = (nr_2d_00
[bit_i
][bit_j
] << 2U) - distrib_nr_child
;
1147 /* Consider worse distance above best */
1148 if (distance_to_best
[1] > 0 && distance_to_best
[1] > distance_to_best
[0])
1149 distance_to_best
[0] = distance_to_best
[1];
1150 if (distance_to_best
[2] > 0 && distance_to_best
[2] > distance_to_best
[0])
1151 distance_to_best
[0] = distance_to_best
[2];
1152 if (distance_to_best
[3] > 0 && distance_to_best
[3] > distance_to_best
[0])
1153 distance_to_best
[0] = distance_to_best
[3];
1156 * If our worse distance is better than overall,
1157 * we become new best candidate.
1159 if (distance_to_best
[0] < overall_best_distance
) {
1160 overall_best_distance
= distance_to_best
[0];
1167 dbg_printf("2 dimensions pool bit selection: (%u,%u)\n", bitsel
[0], bitsel
[1]);
1169 /* Return our bit selection */
1170 _bitsel
[0] = bitsel
[0];
1171 _bitsel
[1] = bitsel
[1];
1175 * ja_node_recompact_add: recompact a node, adding a new child.
1176 * Return 0 on success, -EAGAIN if need to retry, or other negative
1177 * error value otherwise.
1180 int ja_node_recompact(enum ja_recompact mode
,
1182 unsigned int old_type_index
,
1183 const struct cds_ja_type
*old_type
,
1184 struct cds_ja_inode
*old_node
,
1185 struct cds_ja_shadow_node
*shadow_node
,
1186 struct cds_ja_inode_flag
**old_node_flag_ptr
, uint8_t n
,
1187 struct cds_ja_inode_flag
*child_node_flag
,
1188 struct cds_ja_inode_flag
**nullify_node_flag_ptr
)
1190 unsigned int new_type_index
;
1191 struct cds_ja_inode
*new_node
;
1192 struct cds_ja_shadow_node
*new_shadow_node
= NULL
;
1193 const struct cds_ja_type
*new_type
;
1194 struct cds_ja_inode_flag
*new_node_flag
, *old_node_flag
;
1198 old_node_flag
= *old_node_flag_ptr
;
1201 case JA_RECOMPACT_ADD_SAME
:
1202 if (old_type
->type_class
== RCU_JA_POOL
) {
1204 * For pool type, try redistributing
1205 * into a different distribution of same
1206 * size if we have not reached limits.
1208 if (shadow_node
->nr_child
+ 1 > old_type
->max_child
) {
1209 new_type_index
= old_type_index
+ 1;
1210 } else if (shadow_node
->nr_child
+ 1 < old_type
->min_child
) {
1211 new_type_index
= old_type_index
- 1;
1213 new_type_index
= old_type_index
;
1216 new_type_index
= old_type_index
;
1219 case JA_RECOMPACT_ADD_NEXT
:
1220 if (!shadow_node
|| old_type_index
== NODE_INDEX_NULL
) {
1223 if (old_type
->type_class
== RCU_JA_POOL
) {
1225 * For pool type, try redistributing
1226 * into a different distribution of same
1227 * size if we have not reached limits.
1229 if (shadow_node
->nr_child
+ 1 > old_type
->max_child
) {
1230 new_type_index
= old_type_index
+ 1;
1232 new_type_index
= old_type_index
;
1235 new_type_index
= old_type_index
+ 1;
1239 case JA_RECOMPACT_DEL
:
1240 if (old_type_index
== 0) {
1241 new_type_index
= NODE_INDEX_NULL
;
1243 if (old_type
->type_class
== RCU_JA_POOL
) {
1245 * For pool type, try redistributing
1246 * into a different distribution of same
1247 * size if we have not reached limits.
1249 if (shadow_node
->nr_child
- 1 < old_type
->min_child
) {
1250 new_type_index
= old_type_index
- 1;
1252 new_type_index
= old_type_index
;
1255 new_type_index
= old_type_index
- 1;
1263 retry
: /* for fallback */
1264 dbg_printf("Recompact from type %d to type %d\n",
1265 old_type_index
, new_type_index
);
1266 new_type
= &ja_types
[new_type_index
];
1267 if (new_type_index
!= NODE_INDEX_NULL
) {
1268 new_node
= alloc_cds_ja_node(new_type
);
1272 if (new_type
->type_class
== RCU_JA_POOL
) {
1273 switch (new_type
->nr_pool_order
) {
1276 unsigned int node_distrib_bitsel
;
1278 node_distrib_bitsel
=
1279 ja_node_sum_distribution_1d(mode
, ja
,
1280 old_type_index
, old_type
,
1281 old_node
, shadow_node
,
1283 nullify_node_flag_ptr
);
1284 assert(!((unsigned long) new_node
& JA_POOL_1D_MASK
));
1285 new_node_flag
= ja_node_flag_pool_1d(new_node
,
1286 new_type_index
, node_distrib_bitsel
);
1291 unsigned int node_distrib_bitsel
[2];
1293 ja_node_sum_distribution_2d(mode
, ja
,
1294 old_type_index
, old_type
,
1295 old_node
, shadow_node
,
1297 nullify_node_flag_ptr
,
1298 node_distrib_bitsel
);
1299 assert(!((unsigned long) new_node
& JA_POOL_1D_MASK
));
1300 assert(!((unsigned long) new_node
& JA_POOL_2D_MASK
));
1301 new_node_flag
= ja_node_flag_pool_2d(new_node
,
1302 new_type_index
, node_distrib_bitsel
);
1309 new_node_flag
= ja_node_flag(new_node
, new_type_index
);
1312 dbg_printf("Recompact inherit lock from %p\n", shadow_node
);
1313 new_shadow_node
= rcuja_shadow_set(ja
->ht
, new_node_flag
, shadow_node
, ja
);
1314 if (!new_shadow_node
) {
1319 new_shadow_node
->fallback_removal_count
=
1320 JA_FALLBACK_REMOVAL_COUNT
;
1323 new_node_flag
= NULL
;
1326 assert(mode
!= JA_RECOMPACT_ADD_NEXT
|| old_type
->type_class
!= RCU_JA_PIGEON
);
1328 if (new_type_index
== NODE_INDEX_NULL
)
1331 switch (old_type
->type_class
) {
1335 ja_linear_node_get_nr_child(old_type
, old_node
);
1338 for (i
= 0; i
< nr_child
; i
++) {
1339 struct cds_ja_inode_flag
*iter
;
1342 ja_linear_node_get_ith_pos(old_type
, old_node
, i
, &v
, &iter
);
1345 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1347 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1350 if (new_type
->type_class
== RCU_JA_POOL
&& ret
) {
1351 goto fallback_toosmall
;
1359 unsigned int pool_nr
;
1361 for (pool_nr
= 0; pool_nr
< (1U << old_type
->nr_pool_order
); pool_nr
++) {
1362 struct cds_ja_inode
*pool
=
1363 ja_pool_node_get_ith_pool(old_type
,
1366 ja_linear_node_get_nr_child(old_type
, pool
);
1369 for (j
= 0; j
< nr_child
; j
++) {
1370 struct cds_ja_inode_flag
*iter
;
1373 ja_linear_node_get_ith_pos(old_type
, pool
,
1377 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1379 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1382 if (new_type
->type_class
== RCU_JA_POOL
1384 goto fallback_toosmall
;
1392 assert(mode
== JA_RECOMPACT_ADD_NEXT
);
1399 assert(mode
== JA_RECOMPACT_DEL
);
1400 nr_child
= shadow_node
->nr_child
;
1401 for (i
= 0; i
< nr_child
; i
++) {
1402 struct cds_ja_inode_flag
*iter
;
1404 iter
= ja_pigeon_node_get_ith_pos(old_type
, old_node
, i
);
1407 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1409 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1412 if (new_type
->type_class
== RCU_JA_POOL
&& ret
) {
1413 goto fallback_toosmall
;
1426 if (mode
== JA_RECOMPACT_ADD_NEXT
|| mode
== JA_RECOMPACT_ADD_SAME
) {
1428 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1430 n
, child_node_flag
);
1431 if (new_type
->type_class
== RCU_JA_POOL
&& ret
) {
1432 goto fallback_toosmall
;
1438 dbg_printf("Using fallback for %u children, node type index: %u, mode %s\n",
1439 new_shadow_node
->nr_child
, old_type_index
, mode
== JA_RECOMPACT_ADD_NEXT
? "add_next" :
1440 (mode
== JA_RECOMPACT_DEL
? "del" : "add_same"));
1441 uatomic_inc(&node_fallback_count_distribution
[new_shadow_node
->nr_child
]);
1444 /* Return pointer to new recompacted node through old_node_flag_ptr */
1445 *old_node_flag_ptr
= new_node_flag
;
1449 flags
= RCUJA_SHADOW_CLEAR_FREE_NODE
;
1451 * It is OK to free the lock associated with a node
1452 * going to NULL, since we are holding the parent lock.
1453 * This synchronizes removal with re-add of that node.
1455 if (new_type_index
== NODE_INDEX_NULL
)
1456 flags
= RCUJA_SHADOW_CLEAR_FREE_LOCK
;
1457 ret
= rcuja_shadow_clear(ja
->ht
, old_node_flag
, shadow_node
,
1467 /* fallback if next pool is too small */
1468 assert(new_shadow_node
);
1469 ret
= rcuja_shadow_clear(ja
->ht
, new_node_flag
, new_shadow_node
,
1470 RCUJA_SHADOW_CLEAR_FREE_NODE
);
1474 case JA_RECOMPACT_ADD_SAME
:
1476 * JA_RECOMPACT_ADD_SAME is only triggered if a linear
1477 * node within a pool has unused entries. It should
1478 * therefore _never_ be too small.
1483 case JA_RECOMPACT_ADD_NEXT
:
1485 const struct cds_ja_type
*next_type
;
1488 * Recompaction attempt on add failed. Should only
1489 * happen if target node type is pool. Caused by
1490 * hard-to-split distribution. Recompact using the next
1491 * distribution size.
1493 assert(new_type
->type_class
== RCU_JA_POOL
);
1494 next_type
= &ja_types
[new_type_index
+ 1];
1496 * Try going to the next pool size if our population
1497 * fits within its range. This is not flagged as a
1500 if (shadow_node
->nr_child
+ 1 >= next_type
->min_child
1501 && shadow_node
->nr_child
+ 1 <= next_type
->max_child
) {
1506 dbg_printf("Add fallback to type %d\n", new_type_index
);
1507 uatomic_inc(&ja
->nr_fallback
);
1513 case JA_RECOMPACT_DEL
:
1515 * Recompaction attempt on delete failed. Should only
1516 * happen if target node type is pool. This is caused by
1517 * a hard-to-split distribution. Recompact on same node
1518 * size, but flag current node as "fallback" to ensure
1519 * we don't attempt recompaction before some activity
1520 * has reshuffled our node.
1522 assert(new_type
->type_class
== RCU_JA_POOL
);
1523 new_type_index
= old_type_index
;
1524 dbg_printf("Delete fallback keeping type %d\n", new_type_index
);
1525 uatomic_inc(&ja
->nr_fallback
);
1534 * Last resort fallback: pigeon.
1536 new_type_index
= (1UL << JA_TYPE_BITS
) - 1;
1537 dbg_printf("Fallback to type %d\n", new_type_index
);
1538 uatomic_inc(&ja
->nr_fallback
);
1544 * Return 0 on success, -EAGAIN if need to retry, or other negative
1545 * error value otherwise.
1548 int ja_node_set_nth(struct cds_ja
*ja
,
1549 struct cds_ja_inode_flag
**node_flag
, uint8_t n
,
1550 struct cds_ja_inode_flag
*child_node_flag
,
1551 struct cds_ja_shadow_node
*shadow_node
)
1554 unsigned int type_index
;
1555 const struct cds_ja_type
*type
;
1556 struct cds_ja_inode
*node
;
1558 dbg_printf("ja_node_set_nth for n=%u, node %p, shadow %p\n",
1559 (unsigned int) n
, ja_node_ptr(*node_flag
), shadow_node
);
1561 node
= ja_node_ptr(*node_flag
);
1562 type_index
= ja_node_type(*node_flag
);
1563 type
= &ja_types
[type_index
];
1564 ret
= _ja_node_set_nth(type
, node
, *node_flag
, shadow_node
,
1565 n
, child_node_flag
);
1568 /* Not enough space in node, need to recompact to next type. */
1569 ret
= ja_node_recompact(JA_RECOMPACT_ADD_NEXT
, ja
, type_index
, type
, node
,
1570 shadow_node
, node_flag
, n
, child_node_flag
, NULL
);
1573 /* Node needs to be recompacted. */
1574 ret
= ja_node_recompact(JA_RECOMPACT_ADD_SAME
, ja
, type_index
, type
, node
,
1575 shadow_node
, node_flag
, n
, child_node_flag
, NULL
);
1582 * Return 0 on success, -EAGAIN if need to retry, or other negative
1583 * error value otherwise.
1586 int ja_node_clear_ptr(struct cds_ja
*ja
,
1587 struct cds_ja_inode_flag
**node_flag_ptr
, /* Pointer to location to nullify */
1588 struct cds_ja_inode_flag
**parent_node_flag_ptr
, /* Address of parent ptr in its parent */
1589 struct cds_ja_shadow_node
*shadow_node
, /* of parent */
1593 unsigned int type_index
;
1594 const struct cds_ja_type
*type
;
1595 struct cds_ja_inode
*node
;
1597 dbg_printf("ja_node_clear_ptr for node %p, shadow %p, target ptr %p\n",
1598 ja_node_ptr(*parent_node_flag_ptr
), shadow_node
, node_flag_ptr
);
1600 node
= ja_node_ptr(*parent_node_flag_ptr
);
1601 type_index
= ja_node_type(*parent_node_flag_ptr
);
1602 type
= &ja_types
[type_index
];
1603 ret
= _ja_node_clear_ptr(type
, node
, *parent_node_flag_ptr
, shadow_node
, node_flag_ptr
, n
);
1604 if (ret
== -EFBIG
) {
1605 /* Should try recompaction. */
1606 ret
= ja_node_recompact(JA_RECOMPACT_DEL
, ja
, type_index
, type
, node
,
1607 shadow_node
, parent_node_flag_ptr
, n
, NULL
,
1613 struct cds_hlist_head
cds_ja_lookup(struct cds_ja
*ja
, uint64_t key
)
1615 unsigned int tree_depth
, i
;
1616 struct cds_ja_inode_flag
*node_flag
;
1617 struct cds_hlist_head head
= { NULL
};
1619 if (caa_unlikely(key
> ja
->key_max
))
1621 tree_depth
= ja
->tree_depth
;
1622 node_flag
= rcu_dereference(ja
->root
);
1624 /* level 0: root node */
1625 if (!ja_node_ptr(node_flag
))
1628 for (i
= 1; i
< tree_depth
; i
++) {
1631 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (tree_depth
- i
- 1)));
1632 node_flag
= ja_node_get_nth(node_flag
, NULL
, NULL
, NULL
,
1634 dbg_printf("cds_ja_lookup iter key lookup %u finds node_flag %p\n",
1635 (unsigned int) iter_key
, node_flag
);
1636 if (!ja_node_ptr(node_flag
))
1640 /* Last level lookup succeded. We got an actual match. */
1641 head
.next
= (struct cds_hlist_node
*) node_flag
;
1646 * We reached an unpopulated node. Create it and the children we need,
1647 * and then attach the entire branch to the current node. This may
1648 * trigger recompaction of the current node. Locks needed: node lock
1649 * (for add), and, possibly, parent node lock (to update pointer due to
1650 * node recompaction).
1652 * First take node lock, check if recompaction is needed, then take
1653 * parent lock (if needed). Then we can proceed to create the new
1654 * branch. Publish the new branch, and release locks.
1655 * TODO: we currently always take the parent lock even when not needed.
1658 int ja_attach_node(struct cds_ja
*ja
,
1659 struct cds_ja_inode_flag
**attach_node_flag_ptr
,
1660 struct cds_ja_inode_flag
*attach_node_flag
,
1661 struct cds_ja_inode_flag
**node_flag_ptr
,
1662 struct cds_ja_inode_flag
*node_flag
,
1663 struct cds_ja_inode_flag
*parent_node_flag
,
1666 struct cds_ja_node
*child_node
)
1668 struct cds_ja_shadow_node
*shadow_node
= NULL
,
1669 *parent_shadow_node
= NULL
;
1670 struct cds_ja_inode
*node
= ja_node_ptr(node_flag
);
1671 struct cds_ja_inode
*parent_node
= ja_node_ptr(parent_node_flag
);
1672 struct cds_hlist_head head
;
1673 struct cds_ja_inode_flag
*iter_node_flag
, *iter_dest_node_flag
;
1675 struct cds_ja_inode_flag
*created_nodes
[JA_MAX_DEPTH
];
1676 int nr_created_nodes
= 0;
1678 dbg_printf("Attach node at level %u (node %p, node_flag %p)\n",
1679 level
, node
, node_flag
);
1682 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
, node_flag
);
1688 parent_shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
1690 if (!parent_shadow_node
) {
1696 if (node_flag_ptr
&& ja_node_ptr(*node_flag_ptr
)) {
1698 * Target node has been updated between RCU lookup and
1699 * lock acquisition. We need to re-try lookup and
1706 if (attach_node_flag_ptr
&& ja_node_ptr(*attach_node_flag_ptr
) !=
1707 ja_node_ptr(attach_node_flag
)) {
1709 * Target node has been updated between RCU lookup and
1710 * lock acquisition. We need to re-try lookup and
1717 /* Create new branch, starting from bottom */
1718 CDS_INIT_HLIST_HEAD(&head
);
1719 cds_hlist_add_head_rcu(&child_node
->list
, &head
);
1720 iter_node_flag
= (struct cds_ja_inode_flag
*) head
.next
;
1722 for (i
= ja
->tree_depth
; i
> (int) level
; i
--) {
1725 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (ja
->tree_depth
- i
)));
1726 dbg_printf("branch creation level %d, key %u\n",
1727 i
- 1, (unsigned int) iter_key
);
1728 iter_dest_node_flag
= NULL
;
1729 ret
= ja_node_set_nth(ja
, &iter_dest_node_flag
,
1735 created_nodes
[nr_created_nodes
++] = iter_dest_node_flag
;
1736 iter_node_flag
= iter_dest_node_flag
;
1742 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (ja
->tree_depth
- level
)));
1743 /* We need to use set_nth on the previous level. */
1744 iter_dest_node_flag
= node_flag
;
1745 ret
= ja_node_set_nth(ja
, &iter_dest_node_flag
,
1751 created_nodes
[nr_created_nodes
++] = iter_dest_node_flag
;
1752 iter_node_flag
= iter_dest_node_flag
;
1755 /* Publish new branch */
1756 dbg_printf("Publish branch %p, replacing %p\n",
1757 iter_node_flag
, *attach_node_flag_ptr
);
1758 rcu_assign_pointer(*attach_node_flag_ptr
, iter_node_flag
);
1765 for (i
= 0; i
< nr_created_nodes
; i
++) {
1769 flags
= RCUJA_SHADOW_CLEAR_FREE_LOCK
;
1771 flags
|= RCUJA_SHADOW_CLEAR_FREE_NODE
;
1772 tmpret
= rcuja_shadow_clear(ja
->ht
,
1780 if (parent_shadow_node
)
1781 rcuja_shadow_unlock(parent_shadow_node
);
1784 rcuja_shadow_unlock(shadow_node
);
1790 * Lock the parent containing the hlist head pointer, and add node to list of
1791 * duplicates. Failure can happen if concurrent update changes the
1792 * parent before we get the lock. We return -EAGAIN in that case.
1793 * Return 0 on success, negative error value on failure.
1796 int ja_chain_node(struct cds_ja
*ja
,
1797 struct cds_ja_inode_flag
*parent_node_flag
,
1798 struct cds_ja_inode_flag
**node_flag_ptr
,
1799 struct cds_ja_inode_flag
*node_flag
,
1800 struct cds_hlist_head
*head
,
1801 struct cds_ja_node
*node
)
1803 struct cds_ja_shadow_node
*shadow_node
;
1806 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
, parent_node_flag
);
1810 if (ja_node_ptr(*node_flag_ptr
) != ja_node_ptr(node_flag
)) {
1814 cds_hlist_add_head_rcu(&node
->list
, head
);
1816 rcuja_shadow_unlock(shadow_node
);
1820 int cds_ja_add(struct cds_ja
*ja
, uint64_t key
,
1821 struct cds_ja_node
*new_node
)
1823 unsigned int tree_depth
, i
;
1824 struct cds_ja_inode_flag
**attach_node_flag_ptr
,
1826 struct cds_ja_inode_flag
*node_flag
,
1832 if (caa_unlikely(key
> ja
->key_max
)) {
1835 tree_depth
= ja
->tree_depth
;
1838 dbg_printf("cds_ja_add attempt: key %" PRIu64
", node %p\n",
1840 parent2_node_flag
= NULL
;
1842 (struct cds_ja_inode_flag
*) &ja
->root
; /* Use root ptr address as key for mutex */
1843 attach_node_flag_ptr
= &ja
->root
;
1844 attach_node_flag
= rcu_dereference(ja
->root
);
1845 node_flag_ptr
= &ja
->root
;
1846 node_flag
= rcu_dereference(ja
->root
);
1848 /* Iterate on all internal levels */
1849 for (i
= 1; i
< tree_depth
; i
++) {
1852 dbg_printf("cds_ja_add iter attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
1853 attach_node_flag_ptr
, node_flag_ptr
, node_flag
);
1854 if (!ja_node_ptr(node_flag
)) {
1855 ret
= ja_attach_node(ja
, attach_node_flag_ptr
,
1861 if (ret
== -EAGAIN
|| ret
== -EEXIST
)
1866 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (tree_depth
- i
- 1)));
1867 parent2_node_flag
= parent_node_flag
;
1868 parent_node_flag
= node_flag
;
1869 node_flag
= ja_node_get_nth(node_flag
,
1870 &attach_node_flag_ptr
,
1874 dbg_printf("cds_ja_add iter key lookup %u finds node_flag %p attach_node_flag_ptr %p node_flag_ptr %p\n",
1875 (unsigned int) iter_key
, node_flag
,
1876 attach_node_flag_ptr
,
1881 * We reached bottom of tree, simply add node to last internal
1882 * level, or chain it if key is already present.
1884 if (!ja_node_ptr(node_flag
)) {
1885 dbg_printf("cds_ja_add attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
1886 attach_node_flag_ptr
, node_flag_ptr
, node_flag
);
1887 ret
= ja_attach_node(ja
, attach_node_flag_ptr
,
1889 node_flag_ptr
, parent_node_flag
,
1890 parent2_node_flag
, key
, i
, new_node
);
1892 ret
= ja_chain_node(ja
,
1896 (struct cds_hlist_head
*) attach_node_flag_ptr
,
1899 if (ret
== -EAGAIN
|| ret
== -EEXIST
)
1906 * Note: there is no need to lookup the pointer address associated with
1907 * each node's nth item after taking the lock: it's already been done by
1908 * cds_ja_del while holding the rcu read-side lock, and our node rules
1909 * ensure that when a match value -> pointer is found in a node, it is
1910 * _NEVER_ changed for that node without recompaction, and recompaction
1911 * reallocates the node.
1912 * However, when a child is removed from "linear" nodes, its pointer
1913 * is set to NULL. We therefore check, while holding the locks, if this
1914 * pointer is NULL, and return -ENOENT to the caller if it is the case.
1917 int ja_detach_node(struct cds_ja
*ja
,
1918 struct cds_ja_inode_flag
**snapshot
,
1919 struct cds_ja_inode_flag
***snapshot_ptr
,
1920 uint8_t *snapshot_n
,
1923 struct cds_ja_node
*node
)
1925 struct cds_ja_shadow_node
*shadow_nodes
[JA_MAX_DEPTH
];
1926 struct cds_ja_inode_flag
**node_flag_ptr
= NULL
,
1927 *parent_node_flag
= NULL
,
1928 **parent_node_flag_ptr
= NULL
;
1929 struct cds_ja_inode_flag
*iter_node_flag
;
1930 int ret
, i
, nr_shadow
= 0, nr_clear
= 0, nr_branch
= 0;
1933 assert(nr_snapshot
== ja
->tree_depth
+ 1);
1936 * From the last internal level node going up, get the node
1937 * lock, check if the node has only one child left. If it is the
1938 * case, we continue iterating upward. When we reach a node
1939 * which has more that one child left, we lock the parent, and
1940 * proceed to the node deletion (removing its children too).
1942 for (i
= nr_snapshot
- 2; i
>= 1; i
--) {
1943 struct cds_ja_shadow_node
*shadow_node
;
1945 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
1951 shadow_nodes
[nr_shadow
++] = shadow_node
;
1954 * Check if node has been removed between RCU
1955 * lookup and lock acquisition.
1957 assert(snapshot_ptr
[i
+ 1]);
1958 if (ja_node_ptr(*snapshot_ptr
[i
+ 1])
1959 != ja_node_ptr(snapshot
[i
+ 1])) {
1964 assert(shadow_node
->nr_child
> 0);
1965 if (shadow_node
->nr_child
== 1 && i
> 1)
1968 if (shadow_node
->nr_child
> 1 || i
== 1) {
1969 /* Lock parent and break */
1970 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
1976 shadow_nodes
[nr_shadow
++] = shadow_node
;
1979 * Check if node has been removed between RCU
1980 * lookup and lock acquisition.
1982 assert(snapshot_ptr
[i
]);
1983 if (ja_node_ptr(*snapshot_ptr
[i
])
1984 != ja_node_ptr(snapshot
[i
])) {
1989 node_flag_ptr
= snapshot_ptr
[i
+ 1];
1990 n
= snapshot_n
[i
+ 1];
1991 parent_node_flag_ptr
= snapshot_ptr
[i
];
1992 parent_node_flag
= snapshot
[i
];
1996 * Lock parent's parent, in case we need
1997 * to recompact parent.
1999 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
2005 shadow_nodes
[nr_shadow
++] = shadow_node
;
2008 * Check if node has been removed between RCU
2009 * lookup and lock acquisition.
2011 assert(snapshot_ptr
[i
- 1]);
2012 if (ja_node_ptr(*snapshot_ptr
[i
- 1])
2013 != ja_node_ptr(snapshot
[i
- 1])) {
2024 * At this point, we want to delete all nodes that are about to
2025 * be removed from shadow_nodes (except the last one, which is
2026 * either the root or the parent of the upmost node with 1
2027 * child). OK to free lock here, because RCU read lock is held,
2028 * and free only performed in call_rcu.
2031 for (i
= 0; i
< nr_clear
; i
++) {
2032 ret
= rcuja_shadow_clear(ja
->ht
,
2033 shadow_nodes
[i
]->node_flag
,
2035 RCUJA_SHADOW_CLEAR_FREE_NODE
2036 | RCUJA_SHADOW_CLEAR_FREE_LOCK
);
2040 iter_node_flag
= parent_node_flag
;
2041 /* Remove from parent */
2042 ret
= ja_node_clear_ptr(ja
,
2043 node_flag_ptr
, /* Pointer to location to nullify */
2044 &iter_node_flag
, /* Old new parent ptr in its parent */
2045 shadow_nodes
[nr_branch
- 1], /* of parent */
2050 dbg_printf("ja_detach_node: publish %p instead of %p\n",
2051 iter_node_flag
, *parent_node_flag_ptr
);
2052 /* Update address of parent ptr in its parent */
2053 rcu_assign_pointer(*parent_node_flag_ptr
, iter_node_flag
);
2056 for (i
= 0; i
< nr_shadow
; i
++)
2057 rcuja_shadow_unlock(shadow_nodes
[i
]);
2062 int ja_unchain_node(struct cds_ja
*ja
,
2063 struct cds_ja_inode_flag
*parent_node_flag
,
2064 struct cds_ja_inode_flag
**node_flag_ptr
,
2065 struct cds_ja_inode_flag
*node_flag
,
2066 struct cds_ja_node
*node
)
2068 struct cds_ja_shadow_node
*shadow_node
;
2069 struct cds_hlist_node
*hlist_node
;
2070 struct cds_hlist_head hlist_head
;
2071 int ret
= 0, count
= 0, found
= 0;
2073 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
, parent_node_flag
);
2076 if (ja_node_ptr(*node_flag_ptr
) != ja_node_ptr(node_flag
)) {
2080 hlist_head
.next
= (struct cds_hlist_node
*) ja_node_ptr(node_flag
);
2082 * Retry if another thread removed all but one of duplicates
2083 * since check (this check was performed without lock).
2084 * Ensure that the node we are about to remove is still in the
2085 * list (while holding lock).
2087 cds_hlist_for_each_rcu(hlist_node
, &hlist_head
) {
2089 /* FIXME: currently a work-around */
2090 hlist_node
->prev
= (struct cds_hlist_node
*) node_flag_ptr
;
2093 if (hlist_node
== &node
->list
)
2097 if (!found
|| count
== 1) {
2101 cds_hlist_del_rcu(&node
->list
);
2103 * Validate that we indeed removed the node from linked list.
2105 assert(ja_node_ptr(*node_flag_ptr
) != (struct cds_ja_inode
*) node
);
2107 rcuja_shadow_unlock(shadow_node
);
2112 * Called with RCU read lock held.
2114 int cds_ja_del(struct cds_ja
*ja
, uint64_t key
,
2115 struct cds_ja_node
*node
)
2117 unsigned int tree_depth
, i
;
2118 struct cds_ja_inode_flag
*snapshot
[JA_MAX_DEPTH
];
2119 struct cds_ja_inode_flag
**snapshot_ptr
[JA_MAX_DEPTH
];
2120 uint8_t snapshot_n
[JA_MAX_DEPTH
];
2121 struct cds_ja_inode_flag
*node_flag
;
2122 struct cds_ja_inode_flag
**prev_node_flag_ptr
,
2127 if (caa_unlikely(key
> ja
->key_max
))
2129 tree_depth
= ja
->tree_depth
;
2133 dbg_printf("cds_ja_del attempt: key %" PRIu64
", node %p\n",
2136 /* snapshot for level 0 is only for shadow node lookup */
2139 snapshot_ptr
[nr_snapshot
] = NULL
;
2140 snapshot
[nr_snapshot
++] = (struct cds_ja_inode_flag
*) &ja
->root
;
2141 node_flag
= rcu_dereference(ja
->root
);
2142 prev_node_flag_ptr
= &ja
->root
;
2143 node_flag_ptr
= &ja
->root
;
2145 /* Iterate on all internal levels */
2146 for (i
= 1; i
< tree_depth
; i
++) {
2149 dbg_printf("cds_ja_del iter node_flag %p\n",
2151 if (!ja_node_ptr(node_flag
)) {
2154 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (tree_depth
- i
- 1)));
2155 snapshot_n
[nr_snapshot
+ 1] = iter_key
;
2156 snapshot_ptr
[nr_snapshot
] = prev_node_flag_ptr
;
2157 snapshot
[nr_snapshot
++] = node_flag
;
2158 node_flag
= ja_node_get_nth(node_flag
,
2159 &prev_node_flag_ptr
,
2163 dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p, prev_node_flag_ptr %p\n",
2164 (unsigned int) iter_key
, node_flag
,
2165 prev_node_flag_ptr
);
2168 * We reached bottom of tree, try to find the node we are trying
2169 * to remove. Fail if we cannot find it.
2171 if (!ja_node_ptr(node_flag
)) {
2172 dbg_printf("cds_ja_del: no node found for key %" PRIu64
"\n",
2176 struct cds_hlist_head hlist_head
;
2177 struct cds_hlist_node
*hlist_node
;
2178 struct cds_ja_node
*entry
, *match
= NULL
;
2182 (struct cds_hlist_node
*) ja_node_ptr(node_flag
);
2183 cds_hlist_for_each_entry_rcu(entry
,
2187 dbg_printf("cds_ja_del: compare %p with entry %p\n", node
, entry
);
2193 dbg_printf("cds_ja_del: no node match for node %p key %" PRIu64
"\n", node
, key
);
2199 * Removing last of duplicates. Last snapshot
2200 * does not have a shadow node (external leafs).
2202 snapshot_ptr
[nr_snapshot
] = prev_node_flag_ptr
;
2203 snapshot
[nr_snapshot
++] = node_flag
;
2204 ret
= ja_detach_node(ja
, snapshot
, snapshot_ptr
,
2205 snapshot_n
, nr_snapshot
, key
, node
);
2207 ret
= ja_unchain_node(ja
, snapshot
[nr_snapshot
- 1],
2208 node_flag_ptr
, node_flag
, match
);
2212 * Explanation of -ENOENT handling: caused by concurrent delete
2213 * between RCU lookup and actual removal. Need to re-do the
2214 * lookup and removal attempt.
2216 if (ret
== -EAGAIN
|| ret
== -ENOENT
)
2221 struct cds_ja
*_cds_ja_new(unsigned int key_bits
,
2222 const struct rcu_flavor_struct
*flavor
)
2226 struct cds_ja_shadow_node
*root_shadow_node
;
2228 ja
= calloc(sizeof(*ja
), 1);
2240 ja
->key_max
= (1ULL << key_bits
) - 1;
2243 ja
->key_max
= UINT64_MAX
;
2249 /* ja->root is NULL */
2250 /* tree_depth 0 is for pointer to root node */
2251 ja
->tree_depth
= (key_bits
>> JA_LOG2_BITS_PER_BYTE
) + 1;
2252 assert(ja
->tree_depth
<= JA_MAX_DEPTH
);
2253 ja
->ht
= rcuja_create_ht(flavor
);
2258 * Note: we should not free this node until judy array destroy.
2260 root_shadow_node
= rcuja_shadow_set(ja
->ht
,
2261 (struct cds_ja_inode_flag
*) &ja
->root
,
2263 if (!root_shadow_node
) {
2267 root_shadow_node
->level
= 0;
2272 ret
= rcuja_delete_ht(ja
->ht
);
2282 * Called from RCU read-side CS.
2284 __attribute__((visibility("protected")))
2285 void rcuja_free_all_children(struct cds_ja_shadow_node
*shadow_node
,
2286 struct cds_ja_inode_flag
*node_flag
,
2287 void (*free_node_cb
)(struct rcu_head
*head
))
2289 const struct rcu_flavor_struct
*flavor
;
2290 unsigned int type_index
;
2291 struct cds_ja_inode
*node
;
2292 const struct cds_ja_type
*type
;
2294 flavor
= cds_lfht_rcu_flavor(shadow_node
->ja
->ht
);
2295 node
= ja_node_ptr(node_flag
);
2296 assert(node
!= NULL
);
2297 type_index
= ja_node_type(node_flag
);
2298 type
= &ja_types
[type_index
];
2300 switch (type
->type_class
) {
2304 ja_linear_node_get_nr_child(type
, node
);
2307 for (i
= 0; i
< nr_child
; i
++) {
2308 struct cds_ja_inode_flag
*iter
;
2309 struct cds_hlist_head head
;
2310 struct cds_ja_node
*entry
;
2311 struct cds_hlist_node
*pos
;
2314 ja_linear_node_get_ith_pos(type
, node
, i
, &v
, &iter
);
2317 head
.next
= (struct cds_hlist_node
*) iter
;
2318 cds_hlist_for_each_entry_rcu(entry
, pos
, &head
, list
) {
2319 flavor
->update_call_rcu(&entry
->head
, free_node_cb
);
2326 unsigned int pool_nr
;
2328 for (pool_nr
= 0; pool_nr
< (1U << type
->nr_pool_order
); pool_nr
++) {
2329 struct cds_ja_inode
*pool
=
2330 ja_pool_node_get_ith_pool(type
, node
, pool_nr
);
2332 ja_linear_node_get_nr_child(type
, pool
);
2335 for (j
= 0; j
< nr_child
; j
++) {
2336 struct cds_ja_inode_flag
*iter
;
2337 struct cds_hlist_head head
;
2338 struct cds_ja_node
*entry
;
2339 struct cds_hlist_node
*pos
;
2342 ja_linear_node_get_ith_pos(type
, node
, j
, &v
, &iter
);
2345 head
.next
= (struct cds_hlist_node
*) iter
;
2346 cds_hlist_for_each_entry_rcu(entry
, pos
, &head
, list
) {
2347 flavor
->update_call_rcu(&entry
->head
, free_node_cb
);
2360 nr_child
= shadow_node
->nr_child
;
2361 for (i
= 0; i
< nr_child
; i
++) {
2362 struct cds_ja_inode_flag
*iter
;
2363 struct cds_hlist_head head
;
2364 struct cds_ja_node
*entry
;
2365 struct cds_hlist_node
*pos
;
2367 iter
= ja_pigeon_node_get_ith_pos(type
, node
, i
);
2370 head
.next
= (struct cds_hlist_node
*) iter
;
2371 cds_hlist_for_each_entry_rcu(entry
, pos
, &head
, list
) {
2372 flavor
->update_call_rcu(&entry
->head
, free_node_cb
);
2383 void print_debug_fallback_distribution(void)
2387 fprintf(stderr
, "Fallback node distribution:\n");
2388 for (i
= 0; i
< JA_ENTRY_PER_NODE
; i
++) {
2389 if (!node_fallback_count_distribution
[i
])
2391 fprintf(stderr
, " %3u: %4lu\n",
2392 i
, node_fallback_count_distribution
[i
]);
2397 * There should be no more concurrent add to the judy array while it is
2398 * being destroyed (ensured by the caller).
2400 int cds_ja_destroy(struct cds_ja
*ja
,
2401 void (*free_node_cb
)(struct rcu_head
*head
))
2405 rcuja_shadow_prune(ja
->ht
,
2406 RCUJA_SHADOW_CLEAR_FREE_NODE
| RCUJA_SHADOW_CLEAR_FREE_LOCK
,
2408 ret
= rcuja_delete_ht(ja
->ht
);
2411 if (uatomic_read(&ja
->nr_fallback
))
2413 "[warning] RCU Judy Array used %lu fallback node(s)\n",
2414 uatomic_read(&ja
->nr_fallback
));
2415 print_debug_fallback_distribution();