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
, overall_best_distance
= UINT_MAX
;
981 unsigned int distrib_nr_child
= 0;
983 memset(nr_2d_11
, 0, sizeof(nr_2d_11
));
984 memset(nr_2d_10
, 0, sizeof(nr_2d_10
));
986 switch (type
->type_class
) {
990 ja_linear_node_get_nr_child(type
, node
);
993 for (i
= 0; i
< nr_child
; i
++) {
994 struct cds_ja_inode_flag
*iter
;
997 ja_linear_node_get_ith_pos(type
, node
, i
, &v
, &iter
);
1000 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1002 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1003 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1004 if ((v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1005 nr_2d_11
[bit_i
][bit_j
]++;
1007 if ((v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1008 nr_2d_10
[bit_i
][bit_j
]++;
1010 if (!(v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1011 nr_2d_01
[bit_i
][bit_j
]++;
1013 if (!(v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1014 nr_2d_00
[bit_i
][bit_j
]++;
1024 unsigned int pool_nr
;
1026 for (pool_nr
= 0; pool_nr
< (1U << type
->nr_pool_order
); pool_nr
++) {
1027 struct cds_ja_inode
*pool
=
1028 ja_pool_node_get_ith_pool(type
,
1031 ja_linear_node_get_nr_child(type
, pool
);
1034 for (j
= 0; j
< nr_child
; j
++) {
1035 struct cds_ja_inode_flag
*iter
;
1038 ja_linear_node_get_ith_pos(type
, pool
,
1042 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1044 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1045 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1046 if ((v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1047 nr_2d_11
[bit_i
][bit_j
]++;
1049 if ((v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1050 nr_2d_10
[bit_i
][bit_j
]++;
1052 if (!(v
& (1U << bit_i
)) && (v
& (1U << bit_j
))) {
1053 nr_2d_01
[bit_i
][bit_j
]++;
1055 if (!(v
& (1U << bit_i
)) && !(v
& (1U << bit_j
))) {
1056 nr_2d_00
[bit_i
][bit_j
]++;
1070 assert(mode
== JA_RECOMPACT_DEL
);
1071 nr_child
= shadow_node
->nr_child
;
1072 for (i
= 0; i
< nr_child
; i
++) {
1073 struct cds_ja_inode_flag
*iter
;
1075 iter
= ja_pigeon_node_get_ith_pos(type
, node
, i
);
1078 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1080 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1081 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1082 if ((i
& (1U << bit_i
)) && (i
& (1U << bit_j
))) {
1083 nr_2d_11
[bit_i
][bit_j
]++;
1085 if ((i
& (1U << bit_i
)) && !(i
& (1U << bit_j
))) {
1086 nr_2d_10
[bit_i
][bit_j
]++;
1088 if (!(i
& (1U << bit_i
)) && (i
& (1U << bit_j
))) {
1089 nr_2d_01
[bit_i
][bit_j
]++;
1091 if (!(i
& (1U << bit_i
)) && !(i
& (1U << bit_j
))) {
1092 nr_2d_00
[bit_i
][bit_j
]++;
1101 assert(mode
== JA_RECOMPACT_ADD_NEXT
);
1108 if (mode
== JA_RECOMPACT_ADD_NEXT
|| mode
== JA_RECOMPACT_ADD_SAME
) {
1109 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1110 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1111 if ((n
& (1U << bit_i
)) && (n
& (1U << bit_j
))) {
1112 nr_2d_11
[bit_i
][bit_j
]++;
1114 if ((n
& (1U << bit_i
)) && !(n
& (1U << bit_j
))) {
1115 nr_2d_10
[bit_i
][bit_j
]++;
1117 if (!(n
& (1U << bit_i
)) && (n
& (1U << bit_j
))) {
1118 nr_2d_01
[bit_i
][bit_j
]++;
1120 if (!(n
& (1U << bit_i
)) && !(n
& (1U << bit_j
))) {
1121 nr_2d_00
[bit_i
][bit_j
]++;
1129 * The best bit selector is that for which the number of nodes
1130 * in each sub-class is closest to one-fourth of the number of
1131 * children in the distribution. We calculate the distance using
1132 * 4 times the size of the sub-distribution to eliminate
1135 for (bit_i
= 0; bit_i
< JA_BITS_PER_BYTE
; bit_i
++) {
1136 for (bit_j
= 0; bit_j
< bit_i
; bit_j
++) {
1137 unsigned int distance_to_best
[4];
1139 distance_to_best
[0] = nr_2d_11
[bit_i
][bit_j
];
1140 distance_to_best
[1] = nr_2d_10
[bit_i
][bit_j
];
1141 distance_to_best
[2] = nr_2d_01
[bit_i
][bit_j
];
1142 distance_to_best
[3] = nr_2d_00
[bit_i
][bit_j
];
1144 /* Consider worse distance to best */
1145 if (distance_to_best
[1] > distance_to_best
[0])
1146 distance_to_best
[0] = distance_to_best
[1];
1147 if (distance_to_best
[2] > distance_to_best
[0])
1148 distance_to_best
[0] = distance_to_best
[2];
1149 if (distance_to_best
[3] > distance_to_best
[0])
1150 distance_to_best
[0] = distance_to_best
[3];
1152 * If our worse distance is better than overall,
1153 * we become new best candidate.
1155 if (distance_to_best
[0] < overall_best_distance
) {
1156 overall_best_distance
= distance_to_best
[0];
1163 dbg_printf("2 dimensions pool bit selection: (%u,%u)\n", bitsel
[0], bitsel
[1]);
1165 /* Return our bit selection */
1166 _bitsel
[0] = bitsel
[0];
1167 _bitsel
[1] = bitsel
[1];
1171 * ja_node_recompact_add: recompact a node, adding a new child.
1172 * Return 0 on success, -EAGAIN if need to retry, or other negative
1173 * error value otherwise.
1176 int ja_node_recompact(enum ja_recompact mode
,
1178 unsigned int old_type_index
,
1179 const struct cds_ja_type
*old_type
,
1180 struct cds_ja_inode
*old_node
,
1181 struct cds_ja_shadow_node
*shadow_node
,
1182 struct cds_ja_inode_flag
**old_node_flag_ptr
, uint8_t n
,
1183 struct cds_ja_inode_flag
*child_node_flag
,
1184 struct cds_ja_inode_flag
**nullify_node_flag_ptr
)
1186 unsigned int new_type_index
;
1187 struct cds_ja_inode
*new_node
;
1188 struct cds_ja_shadow_node
*new_shadow_node
= NULL
;
1189 const struct cds_ja_type
*new_type
;
1190 struct cds_ja_inode_flag
*new_node_flag
, *old_node_flag
;
1194 old_node_flag
= *old_node_flag_ptr
;
1197 case JA_RECOMPACT_ADD_SAME
:
1198 if (old_type
->type_class
== RCU_JA_POOL
) {
1200 * For pool type, try redistributing
1201 * into a different distribution of same
1202 * size if we have not reached limits.
1204 if (shadow_node
->nr_child
+ 1 > old_type
->max_child
) {
1205 new_type_index
= old_type_index
+ 1;
1206 } else if (shadow_node
->nr_child
+ 1 < old_type
->min_child
) {
1207 new_type_index
= old_type_index
- 1;
1209 new_type_index
= old_type_index
;
1212 new_type_index
= old_type_index
;
1215 case JA_RECOMPACT_ADD_NEXT
:
1216 if (!shadow_node
|| old_type_index
== NODE_INDEX_NULL
) {
1219 if (old_type
->type_class
== RCU_JA_POOL
) {
1221 * For pool type, try redistributing
1222 * into a different distribution of same
1223 * size if we have not reached limits.
1225 if (shadow_node
->nr_child
+ 1 > old_type
->max_child
) {
1226 new_type_index
= old_type_index
+ 1;
1228 new_type_index
= old_type_index
;
1231 new_type_index
= old_type_index
+ 1;
1235 case JA_RECOMPACT_DEL
:
1236 if (old_type_index
== 0) {
1237 new_type_index
= NODE_INDEX_NULL
;
1239 if (old_type
->type_class
== RCU_JA_POOL
) {
1241 * For pool type, try redistributing
1242 * into a different distribution of same
1243 * size if we have not reached limits.
1245 if (shadow_node
->nr_child
- 1 < old_type
->min_child
) {
1246 new_type_index
= old_type_index
- 1;
1248 new_type_index
= old_type_index
;
1251 new_type_index
= old_type_index
- 1;
1259 retry
: /* for fallback */
1260 dbg_printf("Recompact from type %d to type %d\n",
1261 old_type_index
, new_type_index
);
1262 new_type
= &ja_types
[new_type_index
];
1263 if (new_type_index
!= NODE_INDEX_NULL
) {
1264 new_node
= alloc_cds_ja_node(new_type
);
1268 if (new_type
->type_class
== RCU_JA_POOL
) {
1269 switch (new_type
->nr_pool_order
) {
1272 unsigned int node_distrib_bitsel
;
1274 node_distrib_bitsel
=
1275 ja_node_sum_distribution_1d(mode
, ja
,
1276 old_type_index
, old_type
,
1277 old_node
, shadow_node
,
1279 nullify_node_flag_ptr
);
1280 assert(!((unsigned long) new_node
& JA_POOL_1D_MASK
));
1281 new_node_flag
= ja_node_flag_pool_1d(new_node
,
1282 new_type_index
, node_distrib_bitsel
);
1287 unsigned int node_distrib_bitsel
[2];
1289 ja_node_sum_distribution_2d(mode
, ja
,
1290 old_type_index
, old_type
,
1291 old_node
, shadow_node
,
1293 nullify_node_flag_ptr
,
1294 node_distrib_bitsel
);
1295 assert(!((unsigned long) new_node
& JA_POOL_1D_MASK
));
1296 assert(!((unsigned long) new_node
& JA_POOL_2D_MASK
));
1297 new_node_flag
= ja_node_flag_pool_2d(new_node
,
1298 new_type_index
, node_distrib_bitsel
);
1305 new_node_flag
= ja_node_flag(new_node
, new_type_index
);
1308 dbg_printf("Recompact inherit lock from %p\n", shadow_node
);
1309 new_shadow_node
= rcuja_shadow_set(ja
->ht
, new_node_flag
, shadow_node
, ja
);
1310 if (!new_shadow_node
) {
1315 new_shadow_node
->fallback_removal_count
=
1316 JA_FALLBACK_REMOVAL_COUNT
;
1319 new_node_flag
= NULL
;
1322 assert(mode
!= JA_RECOMPACT_ADD_NEXT
|| old_type
->type_class
!= RCU_JA_PIGEON
);
1324 if (new_type_index
== NODE_INDEX_NULL
)
1327 switch (old_type
->type_class
) {
1331 ja_linear_node_get_nr_child(old_type
, old_node
);
1334 for (i
= 0; i
< nr_child
; i
++) {
1335 struct cds_ja_inode_flag
*iter
;
1338 ja_linear_node_get_ith_pos(old_type
, old_node
, i
, &v
, &iter
);
1341 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1343 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1346 if (new_type
->type_class
== RCU_JA_POOL
&& ret
) {
1347 goto fallback_toosmall
;
1355 unsigned int pool_nr
;
1357 for (pool_nr
= 0; pool_nr
< (1U << old_type
->nr_pool_order
); pool_nr
++) {
1358 struct cds_ja_inode
*pool
=
1359 ja_pool_node_get_ith_pool(old_type
,
1362 ja_linear_node_get_nr_child(old_type
, pool
);
1365 for (j
= 0; j
< nr_child
; j
++) {
1366 struct cds_ja_inode_flag
*iter
;
1369 ja_linear_node_get_ith_pos(old_type
, pool
,
1373 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1375 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1378 if (new_type
->type_class
== RCU_JA_POOL
1380 goto fallback_toosmall
;
1388 assert(mode
== JA_RECOMPACT_ADD_NEXT
);
1395 assert(mode
== JA_RECOMPACT_DEL
);
1396 nr_child
= shadow_node
->nr_child
;
1397 for (i
= 0; i
< nr_child
; i
++) {
1398 struct cds_ja_inode_flag
*iter
;
1400 iter
= ja_pigeon_node_get_ith_pos(old_type
, old_node
, i
);
1403 if (mode
== JA_RECOMPACT_DEL
&& *nullify_node_flag_ptr
== iter
)
1405 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1408 if (new_type
->type_class
== RCU_JA_POOL
&& ret
) {
1409 goto fallback_toosmall
;
1422 if (mode
== JA_RECOMPACT_ADD_NEXT
|| mode
== JA_RECOMPACT_ADD_SAME
) {
1424 ret
= _ja_node_set_nth(new_type
, new_node
, new_node_flag
,
1426 n
, child_node_flag
);
1427 if (new_type
->type_class
== RCU_JA_POOL
&& ret
) {
1428 goto fallback_toosmall
;
1434 dbg_printf("Using fallback for %u children, node type index: %u, mode %s\n",
1435 new_shadow_node
->nr_child
, old_type_index
, mode
== JA_RECOMPACT_ADD_NEXT
? "add_next" :
1436 (mode
== JA_RECOMPACT_DEL
? "del" : "add_same"));
1437 uatomic_inc(&node_fallback_count_distribution
[new_shadow_node
->nr_child
]);
1440 /* Return pointer to new recompacted node through old_node_flag_ptr */
1441 *old_node_flag_ptr
= new_node_flag
;
1445 flags
= RCUJA_SHADOW_CLEAR_FREE_NODE
;
1447 * It is OK to free the lock associated with a node
1448 * going to NULL, since we are holding the parent lock.
1449 * This synchronizes removal with re-add of that node.
1451 if (new_type_index
== NODE_INDEX_NULL
)
1452 flags
= RCUJA_SHADOW_CLEAR_FREE_LOCK
;
1453 ret
= rcuja_shadow_clear(ja
->ht
, old_node_flag
, shadow_node
,
1463 /* fallback if next pool is too small */
1464 assert(new_shadow_node
);
1465 ret
= rcuja_shadow_clear(ja
->ht
, new_node_flag
, new_shadow_node
,
1466 RCUJA_SHADOW_CLEAR_FREE_NODE
);
1470 case JA_RECOMPACT_ADD_SAME
:
1472 * JA_RECOMPACT_ADD_SAME is only triggered if a linear
1473 * node within a pool has unused entries. It should
1474 * therefore _never_ be too small.
1478 case JA_RECOMPACT_ADD_NEXT
:
1480 const struct cds_ja_type
*next_type
;
1483 * Recompaction attempt on add failed. Should only
1484 * happen if target node type is pool. Caused by
1485 * hard-to-split distribution. Recompact using the next
1486 * distribution size.
1488 assert(new_type
->type_class
== RCU_JA_POOL
);
1489 next_type
= &ja_types
[new_type_index
+ 1];
1491 * Try going to the next pool size if our population
1492 * fits within its range. This is not flagged as a
1495 if (shadow_node
->nr_child
+ 1 >= next_type
->min_child
1496 && shadow_node
->nr_child
+ 1 <= next_type
->max_child
) {
1501 dbg_printf("Add fallback to type %d\n", new_type_index
);
1502 uatomic_inc(&ja
->nr_fallback
);
1508 case JA_RECOMPACT_DEL
:
1510 * Recompaction attempt on delete failed. Should only
1511 * happen if target node type is pool. This is caused by
1512 * a hard-to-split distribution. Recompact on same node
1513 * size, but flag current node as "fallback" to ensure
1514 * we don't attempt recompaction before some activity
1515 * has reshuffled our node.
1517 assert(new_type
->type_class
== RCU_JA_POOL
);
1518 new_type_index
= old_type_index
;
1519 dbg_printf("Delete fallback keeping type %d\n", new_type_index
);
1520 uatomic_inc(&ja
->nr_fallback
);
1529 * Last resort fallback: pigeon.
1531 new_type_index
= (1UL << JA_TYPE_BITS
) - 1;
1532 dbg_printf("Fallback to type %d\n", new_type_index
);
1533 uatomic_inc(&ja
->nr_fallback
);
1539 * Return 0 on success, -EAGAIN if need to retry, or other negative
1540 * error value otherwise.
1543 int ja_node_set_nth(struct cds_ja
*ja
,
1544 struct cds_ja_inode_flag
**node_flag
, uint8_t n
,
1545 struct cds_ja_inode_flag
*child_node_flag
,
1546 struct cds_ja_shadow_node
*shadow_node
)
1549 unsigned int type_index
;
1550 const struct cds_ja_type
*type
;
1551 struct cds_ja_inode
*node
;
1553 dbg_printf("ja_node_set_nth for n=%u, node %p, shadow %p\n",
1554 (unsigned int) n
, ja_node_ptr(*node_flag
), shadow_node
);
1556 node
= ja_node_ptr(*node_flag
);
1557 type_index
= ja_node_type(*node_flag
);
1558 type
= &ja_types
[type_index
];
1559 ret
= _ja_node_set_nth(type
, node
, *node_flag
, shadow_node
,
1560 n
, child_node_flag
);
1563 /* Not enough space in node, need to recompact to next type. */
1564 ret
= ja_node_recompact(JA_RECOMPACT_ADD_NEXT
, ja
, type_index
, type
, node
,
1565 shadow_node
, node_flag
, n
, child_node_flag
, NULL
);
1568 /* Node needs to be recompacted. */
1569 ret
= ja_node_recompact(JA_RECOMPACT_ADD_SAME
, ja
, type_index
, type
, node
,
1570 shadow_node
, node_flag
, n
, child_node_flag
, NULL
);
1577 * Return 0 on success, -EAGAIN if need to retry, or other negative
1578 * error value otherwise.
1581 int ja_node_clear_ptr(struct cds_ja
*ja
,
1582 struct cds_ja_inode_flag
**node_flag_ptr
, /* Pointer to location to nullify */
1583 struct cds_ja_inode_flag
**parent_node_flag_ptr
, /* Address of parent ptr in its parent */
1584 struct cds_ja_shadow_node
*shadow_node
, /* of parent */
1588 unsigned int type_index
;
1589 const struct cds_ja_type
*type
;
1590 struct cds_ja_inode
*node
;
1592 dbg_printf("ja_node_clear_ptr for node %p, shadow %p, target ptr %p\n",
1593 ja_node_ptr(*parent_node_flag_ptr
), shadow_node
, node_flag_ptr
);
1595 node
= ja_node_ptr(*parent_node_flag_ptr
);
1596 type_index
= ja_node_type(*parent_node_flag_ptr
);
1597 type
= &ja_types
[type_index
];
1598 ret
= _ja_node_clear_ptr(type
, node
, *parent_node_flag_ptr
, shadow_node
, node_flag_ptr
, n
);
1599 if (ret
== -EFBIG
) {
1600 /* Should try recompaction. */
1601 ret
= ja_node_recompact(JA_RECOMPACT_DEL
, ja
, type_index
, type
, node
,
1602 shadow_node
, parent_node_flag_ptr
, n
, NULL
,
1608 struct cds_hlist_head
cds_ja_lookup(struct cds_ja
*ja
, uint64_t key
)
1610 unsigned int tree_depth
, i
;
1611 struct cds_ja_inode_flag
*node_flag
;
1612 struct cds_hlist_head head
= { NULL
};
1614 if (caa_unlikely(key
> ja
->key_max
))
1616 tree_depth
= ja
->tree_depth
;
1617 node_flag
= rcu_dereference(ja
->root
);
1619 /* level 0: root node */
1620 if (!ja_node_ptr(node_flag
))
1623 for (i
= 1; i
< tree_depth
; i
++) {
1626 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (tree_depth
- i
- 1)));
1627 node_flag
= ja_node_get_nth(node_flag
, NULL
, NULL
, NULL
,
1629 dbg_printf("cds_ja_lookup iter key lookup %u finds node_flag %p\n",
1630 (unsigned int) iter_key
, node_flag
);
1631 if (!ja_node_ptr(node_flag
))
1635 /* Last level lookup succeded. We got an actual match. */
1636 head
.next
= (struct cds_hlist_node
*) node_flag
;
1641 * We reached an unpopulated node. Create it and the children we need,
1642 * and then attach the entire branch to the current node. This may
1643 * trigger recompaction of the current node. Locks needed: node lock
1644 * (for add), and, possibly, parent node lock (to update pointer due to
1645 * node recompaction).
1647 * First take node lock, check if recompaction is needed, then take
1648 * parent lock (if needed). Then we can proceed to create the new
1649 * branch. Publish the new branch, and release locks.
1650 * TODO: we currently always take the parent lock even when not needed.
1653 int ja_attach_node(struct cds_ja
*ja
,
1654 struct cds_ja_inode_flag
**attach_node_flag_ptr
,
1655 struct cds_ja_inode_flag
*attach_node_flag
,
1656 struct cds_ja_inode_flag
**node_flag_ptr
,
1657 struct cds_ja_inode_flag
*node_flag
,
1658 struct cds_ja_inode_flag
*parent_node_flag
,
1661 struct cds_ja_node
*child_node
)
1663 struct cds_ja_shadow_node
*shadow_node
= NULL
,
1664 *parent_shadow_node
= NULL
;
1665 struct cds_ja_inode
*node
= ja_node_ptr(node_flag
);
1666 struct cds_ja_inode
*parent_node
= ja_node_ptr(parent_node_flag
);
1667 struct cds_hlist_head head
;
1668 struct cds_ja_inode_flag
*iter_node_flag
, *iter_dest_node_flag
;
1670 struct cds_ja_inode_flag
*created_nodes
[JA_MAX_DEPTH
];
1671 int nr_created_nodes
= 0;
1673 dbg_printf("Attach node at level %u (node %p, node_flag %p)\n",
1674 level
, node
, node_flag
);
1677 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
, node_flag
);
1683 parent_shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
1685 if (!parent_shadow_node
) {
1691 if (node_flag_ptr
&& ja_node_ptr(*node_flag_ptr
)) {
1693 * Target node has been updated between RCU lookup and
1694 * lock acquisition. We need to re-try lookup and
1701 if (attach_node_flag_ptr
&& ja_node_ptr(*attach_node_flag_ptr
) !=
1702 ja_node_ptr(attach_node_flag
)) {
1704 * Target node has been updated between RCU lookup and
1705 * lock acquisition. We need to re-try lookup and
1712 /* Create new branch, starting from bottom */
1713 CDS_INIT_HLIST_HEAD(&head
);
1714 cds_hlist_add_head_rcu(&child_node
->list
, &head
);
1715 iter_node_flag
= (struct cds_ja_inode_flag
*) head
.next
;
1717 for (i
= ja
->tree_depth
; i
> (int) level
; i
--) {
1720 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (ja
->tree_depth
- i
)));
1721 dbg_printf("branch creation level %d, key %u\n",
1722 i
- 1, (unsigned int) iter_key
);
1723 iter_dest_node_flag
= NULL
;
1724 ret
= ja_node_set_nth(ja
, &iter_dest_node_flag
,
1730 created_nodes
[nr_created_nodes
++] = iter_dest_node_flag
;
1731 iter_node_flag
= iter_dest_node_flag
;
1737 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (ja
->tree_depth
- level
)));
1738 /* We need to use set_nth on the previous level. */
1739 iter_dest_node_flag
= node_flag
;
1740 ret
= ja_node_set_nth(ja
, &iter_dest_node_flag
,
1746 created_nodes
[nr_created_nodes
++] = iter_dest_node_flag
;
1747 iter_node_flag
= iter_dest_node_flag
;
1750 /* Publish new branch */
1751 dbg_printf("Publish branch %p, replacing %p\n",
1752 iter_node_flag
, *attach_node_flag_ptr
);
1753 rcu_assign_pointer(*attach_node_flag_ptr
, iter_node_flag
);
1760 for (i
= 0; i
< nr_created_nodes
; i
++) {
1764 flags
= RCUJA_SHADOW_CLEAR_FREE_LOCK
;
1766 flags
|= RCUJA_SHADOW_CLEAR_FREE_NODE
;
1767 tmpret
= rcuja_shadow_clear(ja
->ht
,
1775 if (parent_shadow_node
)
1776 rcuja_shadow_unlock(parent_shadow_node
);
1779 rcuja_shadow_unlock(shadow_node
);
1785 * Lock the parent containing the hlist head pointer, and add node to list of
1786 * duplicates. Failure can happen if concurrent update changes the
1787 * parent before we get the lock. We return -EAGAIN in that case.
1788 * Return 0 on success, negative error value on failure.
1791 int ja_chain_node(struct cds_ja
*ja
,
1792 struct cds_ja_inode_flag
*parent_node_flag
,
1793 struct cds_ja_inode_flag
**node_flag_ptr
,
1794 struct cds_ja_inode_flag
*node_flag
,
1795 struct cds_hlist_head
*head
,
1796 struct cds_ja_node
*node
)
1798 struct cds_ja_shadow_node
*shadow_node
;
1801 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
, parent_node_flag
);
1805 if (ja_node_ptr(*node_flag_ptr
) != ja_node_ptr(node_flag
)) {
1809 cds_hlist_add_head_rcu(&node
->list
, head
);
1811 rcuja_shadow_unlock(shadow_node
);
1815 int cds_ja_add(struct cds_ja
*ja
, uint64_t key
,
1816 struct cds_ja_node
*new_node
)
1818 unsigned int tree_depth
, i
;
1819 struct cds_ja_inode_flag
**attach_node_flag_ptr
,
1821 struct cds_ja_inode_flag
*node_flag
,
1827 if (caa_unlikely(key
> ja
->key_max
)) {
1830 tree_depth
= ja
->tree_depth
;
1833 dbg_printf("cds_ja_add attempt: key %" PRIu64
", node %p\n",
1835 parent2_node_flag
= NULL
;
1837 (struct cds_ja_inode_flag
*) &ja
->root
; /* Use root ptr address as key for mutex */
1838 attach_node_flag_ptr
= &ja
->root
;
1839 attach_node_flag
= rcu_dereference(ja
->root
);
1840 node_flag_ptr
= &ja
->root
;
1841 node_flag
= rcu_dereference(ja
->root
);
1843 /* Iterate on all internal levels */
1844 for (i
= 1; i
< tree_depth
; i
++) {
1847 dbg_printf("cds_ja_add iter attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
1848 attach_node_flag_ptr
, node_flag_ptr
, node_flag
);
1849 if (!ja_node_ptr(node_flag
)) {
1850 ret
= ja_attach_node(ja
, attach_node_flag_ptr
,
1856 if (ret
== -EAGAIN
|| ret
== -EEXIST
)
1861 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (tree_depth
- i
- 1)));
1862 parent2_node_flag
= parent_node_flag
;
1863 parent_node_flag
= node_flag
;
1864 node_flag
= ja_node_get_nth(node_flag
,
1865 &attach_node_flag_ptr
,
1869 dbg_printf("cds_ja_add iter key lookup %u finds node_flag %p attach_node_flag_ptr %p node_flag_ptr %p\n",
1870 (unsigned int) iter_key
, node_flag
,
1871 attach_node_flag_ptr
,
1876 * We reached bottom of tree, simply add node to last internal
1877 * level, or chain it if key is already present.
1879 if (!ja_node_ptr(node_flag
)) {
1880 dbg_printf("cds_ja_add attach_node_flag_ptr %p node_flag_ptr %p node_flag %p\n",
1881 attach_node_flag_ptr
, node_flag_ptr
, node_flag
);
1882 ret
= ja_attach_node(ja
, attach_node_flag_ptr
,
1884 node_flag_ptr
, parent_node_flag
,
1885 parent2_node_flag
, key
, i
, new_node
);
1887 ret
= ja_chain_node(ja
,
1891 (struct cds_hlist_head
*) attach_node_flag_ptr
,
1894 if (ret
== -EAGAIN
|| ret
== -EEXIST
)
1901 * Note: there is no need to lookup the pointer address associated with
1902 * each node's nth item after taking the lock: it's already been done by
1903 * cds_ja_del while holding the rcu read-side lock, and our node rules
1904 * ensure that when a match value -> pointer is found in a node, it is
1905 * _NEVER_ changed for that node without recompaction, and recompaction
1906 * reallocates the node.
1907 * However, when a child is removed from "linear" nodes, its pointer
1908 * is set to NULL. We therefore check, while holding the locks, if this
1909 * pointer is NULL, and return -ENOENT to the caller if it is the case.
1912 int ja_detach_node(struct cds_ja
*ja
,
1913 struct cds_ja_inode_flag
**snapshot
,
1914 struct cds_ja_inode_flag
***snapshot_ptr
,
1915 uint8_t *snapshot_n
,
1918 struct cds_ja_node
*node
)
1920 struct cds_ja_shadow_node
*shadow_nodes
[JA_MAX_DEPTH
];
1921 struct cds_ja_inode_flag
**node_flag_ptr
= NULL
,
1922 *parent_node_flag
= NULL
,
1923 **parent_node_flag_ptr
= NULL
;
1924 struct cds_ja_inode_flag
*iter_node_flag
;
1925 int ret
, i
, nr_shadow
= 0, nr_clear
= 0, nr_branch
= 0;
1928 assert(nr_snapshot
== ja
->tree_depth
+ 1);
1931 * From the last internal level node going up, get the node
1932 * lock, check if the node has only one child left. If it is the
1933 * case, we continue iterating upward. When we reach a node
1934 * which has more that one child left, we lock the parent, and
1935 * proceed to the node deletion (removing its children too).
1937 for (i
= nr_snapshot
- 2; i
>= 1; i
--) {
1938 struct cds_ja_shadow_node
*shadow_node
;
1940 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
1946 shadow_nodes
[nr_shadow
++] = shadow_node
;
1949 * Check if node has been removed between RCU
1950 * lookup and lock acquisition.
1952 assert(snapshot_ptr
[i
+ 1]);
1953 if (ja_node_ptr(*snapshot_ptr
[i
+ 1])
1954 != ja_node_ptr(snapshot
[i
+ 1])) {
1959 assert(shadow_node
->nr_child
> 0);
1960 if (shadow_node
->nr_child
== 1 && i
> 1)
1963 if (shadow_node
->nr_child
> 1 || i
== 1) {
1964 /* Lock parent and break */
1965 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
1971 shadow_nodes
[nr_shadow
++] = shadow_node
;
1974 * Check if node has been removed between RCU
1975 * lookup and lock acquisition.
1977 assert(snapshot_ptr
[i
]);
1978 if (ja_node_ptr(*snapshot_ptr
[i
])
1979 != ja_node_ptr(snapshot
[i
])) {
1984 node_flag_ptr
= snapshot_ptr
[i
+ 1];
1985 n
= snapshot_n
[i
+ 1];
1986 parent_node_flag_ptr
= snapshot_ptr
[i
];
1987 parent_node_flag
= snapshot
[i
];
1991 * Lock parent's parent, in case we need
1992 * to recompact parent.
1994 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
,
2000 shadow_nodes
[nr_shadow
++] = shadow_node
;
2003 * Check if node has been removed between RCU
2004 * lookup and lock acquisition.
2006 assert(snapshot_ptr
[i
- 1]);
2007 if (ja_node_ptr(*snapshot_ptr
[i
- 1])
2008 != ja_node_ptr(snapshot
[i
- 1])) {
2019 * At this point, we want to delete all nodes that are about to
2020 * be removed from shadow_nodes (except the last one, which is
2021 * either the root or the parent of the upmost node with 1
2022 * child). OK to free lock here, because RCU read lock is held,
2023 * and free only performed in call_rcu.
2026 for (i
= 0; i
< nr_clear
; i
++) {
2027 ret
= rcuja_shadow_clear(ja
->ht
,
2028 shadow_nodes
[i
]->node_flag
,
2030 RCUJA_SHADOW_CLEAR_FREE_NODE
2031 | RCUJA_SHADOW_CLEAR_FREE_LOCK
);
2035 iter_node_flag
= parent_node_flag
;
2036 /* Remove from parent */
2037 ret
= ja_node_clear_ptr(ja
,
2038 node_flag_ptr
, /* Pointer to location to nullify */
2039 &iter_node_flag
, /* Old new parent ptr in its parent */
2040 shadow_nodes
[nr_branch
- 1], /* of parent */
2045 dbg_printf("ja_detach_node: publish %p instead of %p\n",
2046 iter_node_flag
, *parent_node_flag_ptr
);
2047 /* Update address of parent ptr in its parent */
2048 rcu_assign_pointer(*parent_node_flag_ptr
, iter_node_flag
);
2051 for (i
= 0; i
< nr_shadow
; i
++)
2052 rcuja_shadow_unlock(shadow_nodes
[i
]);
2057 int ja_unchain_node(struct cds_ja
*ja
,
2058 struct cds_ja_inode_flag
*parent_node_flag
,
2059 struct cds_ja_inode_flag
**node_flag_ptr
,
2060 struct cds_ja_inode_flag
*node_flag
,
2061 struct cds_ja_node
*node
)
2063 struct cds_ja_shadow_node
*shadow_node
;
2064 struct cds_hlist_node
*hlist_node
;
2065 struct cds_hlist_head hlist_head
;
2066 int ret
= 0, count
= 0, found
= 0;
2068 shadow_node
= rcuja_shadow_lookup_lock(ja
->ht
, parent_node_flag
);
2071 if (ja_node_ptr(*node_flag_ptr
) != ja_node_ptr(node_flag
)) {
2075 hlist_head
.next
= (struct cds_hlist_node
*) ja_node_ptr(node_flag
);
2077 * Retry if another thread removed all but one of duplicates
2078 * since check (this check was performed without lock).
2079 * Ensure that the node we are about to remove is still in the
2080 * list (while holding lock).
2082 cds_hlist_for_each_rcu(hlist_node
, &hlist_head
) {
2084 /* FIXME: currently a work-around */
2085 hlist_node
->prev
= (struct cds_hlist_node
*) node_flag_ptr
;
2088 if (hlist_node
== &node
->list
)
2092 if (!found
|| count
== 1) {
2096 cds_hlist_del_rcu(&node
->list
);
2098 * Validate that we indeed removed the node from linked list.
2100 assert(ja_node_ptr(*node_flag_ptr
) != (struct cds_ja_inode
*) node
);
2102 rcuja_shadow_unlock(shadow_node
);
2107 * Called with RCU read lock held.
2109 int cds_ja_del(struct cds_ja
*ja
, uint64_t key
,
2110 struct cds_ja_node
*node
)
2112 unsigned int tree_depth
, i
;
2113 struct cds_ja_inode_flag
*snapshot
[JA_MAX_DEPTH
];
2114 struct cds_ja_inode_flag
**snapshot_ptr
[JA_MAX_DEPTH
];
2115 uint8_t snapshot_n
[JA_MAX_DEPTH
];
2116 struct cds_ja_inode_flag
*node_flag
;
2117 struct cds_ja_inode_flag
**prev_node_flag_ptr
,
2122 if (caa_unlikely(key
> ja
->key_max
))
2124 tree_depth
= ja
->tree_depth
;
2128 dbg_printf("cds_ja_del attempt: key %" PRIu64
", node %p\n",
2131 /* snapshot for level 0 is only for shadow node lookup */
2134 snapshot_ptr
[nr_snapshot
] = NULL
;
2135 snapshot
[nr_snapshot
++] = (struct cds_ja_inode_flag
*) &ja
->root
;
2136 node_flag
= rcu_dereference(ja
->root
);
2137 prev_node_flag_ptr
= &ja
->root
;
2138 node_flag_ptr
= &ja
->root
;
2140 /* Iterate on all internal levels */
2141 for (i
= 1; i
< tree_depth
; i
++) {
2144 dbg_printf("cds_ja_del iter node_flag %p\n",
2146 if (!ja_node_ptr(node_flag
)) {
2149 iter_key
= (uint8_t) (key
>> (JA_BITS_PER_BYTE
* (tree_depth
- i
- 1)));
2150 snapshot_n
[nr_snapshot
+ 1] = iter_key
;
2151 snapshot_ptr
[nr_snapshot
] = prev_node_flag_ptr
;
2152 snapshot
[nr_snapshot
++] = node_flag
;
2153 node_flag
= ja_node_get_nth(node_flag
,
2154 &prev_node_flag_ptr
,
2158 dbg_printf("cds_ja_del iter key lookup %u finds node_flag %p, prev_node_flag_ptr %p\n",
2159 (unsigned int) iter_key
, node_flag
,
2160 prev_node_flag_ptr
);
2163 * We reached bottom of tree, try to find the node we are trying
2164 * to remove. Fail if we cannot find it.
2166 if (!ja_node_ptr(node_flag
)) {
2167 dbg_printf("cds_ja_del: no node found for key %" PRIu64
"\n",
2171 struct cds_hlist_head hlist_head
;
2172 struct cds_hlist_node
*hlist_node
;
2173 struct cds_ja_node
*entry
, *match
= NULL
;
2177 (struct cds_hlist_node
*) ja_node_ptr(node_flag
);
2178 cds_hlist_for_each_entry_rcu(entry
,
2182 dbg_printf("cds_ja_del: compare %p with entry %p\n", node
, entry
);
2188 dbg_printf("cds_ja_del: no node match for node %p key %" PRIu64
"\n", node
, key
);
2194 * Removing last of duplicates. Last snapshot
2195 * does not have a shadow node (external leafs).
2197 snapshot_ptr
[nr_snapshot
] = prev_node_flag_ptr
;
2198 snapshot
[nr_snapshot
++] = node_flag
;
2199 ret
= ja_detach_node(ja
, snapshot
, snapshot_ptr
,
2200 snapshot_n
, nr_snapshot
, key
, node
);
2202 ret
= ja_unchain_node(ja
, snapshot
[nr_snapshot
- 1],
2203 node_flag_ptr
, node_flag
, match
);
2207 * Explanation of -ENOENT handling: caused by concurrent delete
2208 * between RCU lookup and actual removal. Need to re-do the
2209 * lookup and removal attempt.
2211 if (ret
== -EAGAIN
|| ret
== -ENOENT
)
2216 struct cds_ja
*_cds_ja_new(unsigned int key_bits
,
2217 const struct rcu_flavor_struct
*flavor
)
2221 struct cds_ja_shadow_node
*root_shadow_node
;
2223 ja
= calloc(sizeof(*ja
), 1);
2235 ja
->key_max
= (1ULL << key_bits
) - 1;
2238 ja
->key_max
= UINT64_MAX
;
2244 /* ja->root is NULL */
2245 /* tree_depth 0 is for pointer to root node */
2246 ja
->tree_depth
= (key_bits
>> JA_LOG2_BITS_PER_BYTE
) + 1;
2247 assert(ja
->tree_depth
<= JA_MAX_DEPTH
);
2248 ja
->ht
= rcuja_create_ht(flavor
);
2253 * Note: we should not free this node until judy array destroy.
2255 root_shadow_node
= rcuja_shadow_set(ja
->ht
,
2256 (struct cds_ja_inode_flag
*) &ja
->root
,
2258 if (!root_shadow_node
) {
2262 root_shadow_node
->level
= 0;
2267 ret
= rcuja_delete_ht(ja
->ht
);
2277 * Called from RCU read-side CS.
2279 __attribute__((visibility("protected")))
2280 void rcuja_free_all_children(struct cds_ja_shadow_node
*shadow_node
,
2281 struct cds_ja_inode_flag
*node_flag
,
2282 void (*free_node_cb
)(struct rcu_head
*head
))
2284 const struct rcu_flavor_struct
*flavor
;
2285 unsigned int type_index
;
2286 struct cds_ja_inode
*node
;
2287 const struct cds_ja_type
*type
;
2289 flavor
= cds_lfht_rcu_flavor(shadow_node
->ja
->ht
);
2290 node
= ja_node_ptr(node_flag
);
2291 assert(node
!= NULL
);
2292 type_index
= ja_node_type(node_flag
);
2293 type
= &ja_types
[type_index
];
2295 switch (type
->type_class
) {
2299 ja_linear_node_get_nr_child(type
, node
);
2302 for (i
= 0; i
< nr_child
; i
++) {
2303 struct cds_ja_inode_flag
*iter
;
2304 struct cds_hlist_head head
;
2305 struct cds_ja_node
*entry
;
2306 struct cds_hlist_node
*pos
;
2309 ja_linear_node_get_ith_pos(type
, node
, i
, &v
, &iter
);
2312 head
.next
= (struct cds_hlist_node
*) iter
;
2313 cds_hlist_for_each_entry_rcu(entry
, pos
, &head
, list
) {
2314 flavor
->update_call_rcu(&entry
->head
, free_node_cb
);
2321 unsigned int pool_nr
;
2323 for (pool_nr
= 0; pool_nr
< (1U << type
->nr_pool_order
); pool_nr
++) {
2324 struct cds_ja_inode
*pool
=
2325 ja_pool_node_get_ith_pool(type
, node
, pool_nr
);
2327 ja_linear_node_get_nr_child(type
, pool
);
2330 for (j
= 0; j
< nr_child
; j
++) {
2331 struct cds_ja_inode_flag
*iter
;
2332 struct cds_hlist_head head
;
2333 struct cds_ja_node
*entry
;
2334 struct cds_hlist_node
*pos
;
2337 ja_linear_node_get_ith_pos(type
, node
, j
, &v
, &iter
);
2340 head
.next
= (struct cds_hlist_node
*) iter
;
2341 cds_hlist_for_each_entry_rcu(entry
, pos
, &head
, list
) {
2342 flavor
->update_call_rcu(&entry
->head
, free_node_cb
);
2355 nr_child
= shadow_node
->nr_child
;
2356 for (i
= 0; i
< nr_child
; i
++) {
2357 struct cds_ja_inode_flag
*iter
;
2358 struct cds_hlist_head head
;
2359 struct cds_ja_node
*entry
;
2360 struct cds_hlist_node
*pos
;
2362 iter
= ja_pigeon_node_get_ith_pos(type
, node
, i
);
2365 head
.next
= (struct cds_hlist_node
*) iter
;
2366 cds_hlist_for_each_entry_rcu(entry
, pos
, &head
, list
) {
2367 flavor
->update_call_rcu(&entry
->head
, free_node_cb
);
2378 void print_debug_fallback_distribution(void)
2382 fprintf(stderr
, "Fallback node distribution:\n");
2383 for (i
= 0; i
< JA_ENTRY_PER_NODE
; i
++) {
2384 if (!node_fallback_count_distribution
[i
])
2386 fprintf(stderr
, " %3u: %4lu\n",
2387 i
, node_fallback_count_distribution
[i
]);
2392 * There should be no more concurrent add to the judy array while it is
2393 * being destroyed (ensured by the caller).
2395 int cds_ja_destroy(struct cds_ja
*ja
,
2396 void (*free_node_cb
)(struct rcu_head
*head
))
2400 rcuja_shadow_prune(ja
->ht
,
2401 RCUJA_SHADOW_CLEAR_FREE_NODE
| RCUJA_SHADOW_CLEAR_FREE_LOCK
,
2403 ret
= rcuja_delete_ht(ja
->ht
);
2406 if (uatomic_read(&ja
->nr_fallback
))
2408 "[warning] RCU Judy Array used %lu fallback node(s)\n",
2409 uatomic_read(&ja
->nr_fallback
));
2410 print_debug_fallback_distribution();