| 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 | |
| 23 | #include <stdint.h> |
| 24 | #include <urcu/rcuja.h> |
| 25 | #include "rcuja-internal.h" |
| 26 | |
| 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 | |