SoW-2020-0002: Trace Hit Counters: trigger error reporting integration
[lttng-tools.git] / src / common / index-allocator.c
1 /*
2 * Copyright (C) 2020 Francis Deslauriers <francis.deslauriers@efficios.com>
3 *
4 * SPDX-License-Identifier: GPL-2.0-only
5 *
6 */
7
8 #include <assert.h>
9 #include <inttypes.h>
10
11 #include <urcu.h>
12 #include <urcu/list.h>
13
14 #include "macros.h"
15 #include "error.h"
16
17 #include "index-allocator.h"
18
19 struct lttng_index_allocator {
20 struct cds_list_head unused_list;
21 uint64_t size;
22 uint64_t position;
23 };
24
25 struct lttng_index {
26 uint64_t index;
27 struct cds_list_head head;
28 };
29
30 struct lttng_index_allocator *lttng_index_allocator_create(
31 uint64_t index_count)
32 {
33 struct lttng_index_allocator *allocator = NULL;
34
35 allocator = zmalloc(sizeof(*allocator));
36 if (!allocator) {
37 PERROR("Failed to allocate free index queue");
38 goto end;
39 }
40 allocator->size = index_count;
41 allocator->position = 0;
42
43 CDS_INIT_LIST_HEAD(&allocator->unused_list);
44
45 end:
46 return allocator;
47 }
48
49 uint64_t lttng_index_allocator_get_index_count(struct lttng_index_allocator *allocator)
50 {
51 return allocator->size;
52 }
53
54 enum lttng_index_allocator_status lttng_index_allocator_alloc(
55 struct lttng_index_allocator *allocator,
56 uint64_t *allocated_index)
57 {
58 enum lttng_index_allocator_status status =
59 LTTNG_INDEX_ALLOCATOR_STATUS_OK;
60
61 if (cds_list_empty(&allocator->unused_list)) {
62 if (allocator->position >= allocator->size) {
63 /* No indices left. */
64 status = LTTNG_INDEX_ALLOCATOR_STATUS_EMPTY;
65 goto end;
66 }
67
68 *allocated_index = allocator->position++;
69 } else {
70 struct lttng_index *index;
71
72 index = cds_list_first_entry(&allocator->unused_list,
73 typeof(*index), head);
74 cds_list_del(&index->head);
75 *allocated_index = index->index;
76 free(index);
77 }
78
79 end:
80 return status;
81 }
82
83 enum lttng_index_allocator_status lttng_index_allocator_release(
84 struct lttng_index_allocator *allocator, uint64_t idx)
85 {
86 struct lttng_index *index = NULL;
87 enum lttng_index_allocator_status status =
88 LTTNG_INDEX_ALLOCATOR_STATUS_OK;
89
90 assert(idx < allocator->size);
91
92 index = zmalloc(sizeof(*index));
93 if (!index) {
94 PERROR("Failed to allocate free index queue");
95 status = LTTNG_INDEX_ALLOCATOR_STATUS_ERROR;
96 goto end;
97 }
98
99 index->index = idx;
100 cds_list_add_tail(&index->head, &allocator->unused_list);
101
102 end:
103 return status;
104 }
105
106 void lttng_index_allocator_destroy(struct lttng_index_allocator *allocator)
107 {
108 struct lttng_index *index = NULL, *tmp_index = NULL;
109
110 if (!allocator) {
111 return;
112 }
113
114 cds_list_for_each_entry_safe(index, tmp_index,
115 &allocator->unused_list, head) {
116 cds_list_del(&index->head);
117 free(index);
118 }
119
120 free(allocator);
121 }
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