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61009379 MD |
1 | /* |
2 | * rcuja/rcuja.c | |
3 | * | |
4 | * Userspace RCU library - RCU Judy Array | |
5 | * | |
6 | * Copyright 2012 - Mathieu Desnoyers <mathieu.desnoyers@efficios.com> | |
7 | * | |
8 | * This library is free software; you can redistribute it and/or | |
9 | * modify it under the terms of the GNU Lesser General Public | |
10 | * License as published by the Free Software Foundation; either | |
11 | * version 2.1 of the License, or (at your option) any later version. | |
12 | * | |
13 | * This library is distributed in the hope that it will be useful, | |
14 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
15 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU | |
16 | * Lesser General Public License for more details. | |
17 | * | |
18 | * You should have received a copy of the GNU Lesser General Public | |
19 | * License along with this library; if not, write to the Free Software | |
20 | * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA | |
21 | */ | |
22 | ||
e5227865 | 23 | #include <stdint.h> |
61009379 MD |
24 | #include <urcu/rcuja.h> |
25 | #include "rcuja-internal.h" | |
26 | ||
e5227865 MD |
27 | enum rcu_ja_child_type { |
28 | RCU_JA_LINEAR = 0, /* Type A */ | |
29 | /* 32-bit: 1 to 12 children, 8 to 64 bytes */ | |
30 | /* 64-bit: 1 to 14 children, 16 to 128 bytes */ | |
31 | RCU_JA_BITMAP = 1, /* Type B */ | |
32 | /* 32-bit: 13 to 120 children, 128 to 512 bytes */ | |
33 | /* 64-bit: 15 to 124 children, 256 to 1024 bytes */ | |
34 | RCU_JA_PIGEON = 2, /* Type C */ | |
35 | /* 32-bit: 121 to 256 children, 1024 bytes */ | |
36 | /* 64-bit: 125 to 256 children, 2048 bytes */ | |
37 | /* Leaf nodes are implicit from their height in the tree */ | |
38 | }; | |
39 | ||
40 | struct rcu_ja_type_select { | |
41 | enum rcu_ja_child_type type; | |
42 | uint16_t max_nr_child; /* 1 to 256 */ | |
43 | uint16_t node_order; /* node size is (1 << node_order), in bytes */ | |
44 | }; | |
45 | ||
46 | /* | |
47 | * Iteration on the array to find the right node size for the number of | |
48 | * children stops when it reaches max_nr_child == 0 (this is the largest | |
49 | * possible node size, which contains 256 children). | |
50 | */ | |
51 | const struct rcu_ja_type_select ja_select_u32[] = { | |
52 | { .type = RCU_JA_LINEAR, .max_nr_child = 1, .node_order = 3, }, | |
53 | { .type = RCU_JA_LINEAR, .max_nr_child = 3, .node_order = 4, }, | |
54 | { .type = RCU_JA_LINEAR, .max_nr_child = 6, .node_order = 5, }, | |
55 | { .type = RCU_JA_LINEAR, .max_nr_child = 12, .node_order = 6, }, | |
56 | ||
57 | { .type = RCU_JA_BITMAP, .max_nr_child = 24, .node_order = 7, }, | |
58 | { .type = RCU_JA_BITMAP, .max_nr_child = 56, .node_order = 8, }, | |
59 | { .type = RCU_JA_BITMAP, .max_nr_child = 120, .node_order = 9, }, | |
60 | ||
61 | { .type = RCU_JA_PIGEON, .max_nr_child = 256, .node_order = 10, }, | |
62 | }; | |
63 | ||
64 | const struct rcu_ja_type_select ja_select_u64[] = { | |
65 | { .type = RCU_JA_LINEAR, .max_nr_child = 1, .node_order = 4, }, | |
66 | { .type = RCU_JA_LINEAR, .max_nr_child = 3, .node_order = 5, }, | |
67 | { .type = RCU_JA_LINEAR, .max_nr_child = 7, .node_order = 6, }, | |
68 | { .type = RCU_JA_LINEAR, .max_nr_child = 14, .node_order = 7, }, | |
69 | ||
70 | { .type = RCU_JA_BITMAP, .max_nr_child = 28, .node_order = 8, }, | |
71 | { .type = RCU_JA_BITMAP, .max_nr_child = 60, .node_order = 9, }, | |
72 | { .type = RCU_JA_BITMAP, .max_nr_child = 124, .node_order = 10, }, | |
73 | ||
74 | { .type = RCU_JA_PIGEON, .max_nr_child = 256, .node_order = 11, }, | |
75 | }; | |
76 | ||
77 | /* | |
78 | * The rcu_ja_node starts with a byte counting the number of children in | |
79 | * the node. Then, the node-specific data is placed. | |
80 | * TODO: where should we put the mutex for the node ? | |
81 | * -> mutex could be a 0-value node count. | |
82 | * TODO: where do we keep nr children for pigeon ? | |
83 | */ | |
84 | struct rcu_ja_node { | |
85 | char data[]; | |
86 | }; | |
87 | ||
88 | struct rcu_ja_node *create_rcu_ja_node(struct rcu_ja_type_select *sel) | |
89 | { | |
90 | return zmalloc(1 << sel->node_order); | |
91 | } | |
92 | ||
93 | void free_rcu_ja_node(struct rcu_ja_node *node) | |
94 | { | |
95 | free(node); | |
96 | } | |
97 | ||
98 | ||
99 |