Commit | Line | Data |
---|---|---|
e1e02a22 | 1 | /* |
0235b0db MJ |
2 | * SPDX-License-Identifier: MIT |
3 | * | |
e1e02a22 PP |
4 | * Copyright (c) 2018 EfficiOS Inc. and Linux Foundation |
5 | * Copyright (c) 2018 Philippe Proulx <pproulx@efficios.com> | |
e1e02a22 PP |
6 | */ |
7 | ||
0235b0db MJ |
8 | #ifndef BABELTRACE_CTF_WRITER_OBJECT_POOL_INTERNAL_H |
9 | #define BABELTRACE_CTF_WRITER_OBJECT_POOL_INTERNAL_H | |
10 | ||
e1e02a22 PP |
11 | /* |
12 | * This is a generic object pool to avoid memory allocation/deallocation | |
13 | * for objects of which the lifespan is typically short, but which are | |
14 | * created a lot. | |
15 | * | |
16 | * The object pool, thanks to two user functions, knows how to allocate | |
17 | * a brand new object in memory when the pool is empty and how to | |
18 | * destroy an object when we destroy the pool. | |
19 | * | |
20 | * The object pool's user is responsible for: | |
21 | * | |
22 | * * Setting whatever references the object needs to keep and reset some | |
23 | * properties _after_ calling bt_ctf_object_pool_create_object(). This is | |
24 | * typically done in the bt_*_create() function which calls | |
25 | * bt_ctf_object_pool_create_object() (which could call the user-provided | |
26 | * allocation function if the pool is empty) and then sets the | |
27 | * appropriate properties on the possibly recycled object. | |
28 | * | |
29 | * * Releasing whatever references the object keeps _before_ calling | |
30 | * bt_ctf_object_pool_recycle_object(). This is typically done in a custom | |
31 | * bt_*_recycle() function which does the necessary before calling | |
32 | * bt_ctf_object_pool_recycle_object() with an object ready to be reused | |
33 | * at any time. | |
34 | */ | |
35 | ||
36 | #include <glib.h> | |
578e048b MJ |
37 | |
38 | #include "object.h" | |
e1e02a22 PP |
39 | |
40 | typedef void *(*bt_ctf_object_pool_new_object_func)(void *data); | |
41 | typedef void *(*bt_ctf_object_pool_destroy_object_func)(void *obj, void *data); | |
42 | ||
43 | struct bt_ctf_object_pool { | |
44 | /* | |
45 | * Container of recycled objects, owned by this. The array's size | |
46 | * is the pool's capacity. | |
47 | */ | |
48 | GPtrArray *objects; | |
49 | ||
50 | /* | |
51 | * Pool's size, that is, number of elements in the array above, | |
52 | * starting at index 0, which exist as recycled objects. | |
53 | */ | |
54 | size_t size; | |
55 | ||
56 | /* User functions */ | |
57 | struct { | |
58 | /* Allocate a new object in memory */ | |
59 | bt_ctf_object_pool_new_object_func new_object; | |
60 | ||
61 | /* Free direct and indirect memory occupied by object */ | |
62 | bt_ctf_object_pool_destroy_object_func destroy_object; | |
63 | } funcs; | |
64 | ||
65 | /* User data passed to user functions */ | |
66 | void *data; | |
67 | }; | |
68 | ||
69 | /* | |
70 | * Initializes an object pool which is already allocated. | |
71 | */ | |
72 | int bt_ctf_object_pool_initialize(struct bt_ctf_object_pool *pool, | |
73 | bt_ctf_object_pool_new_object_func new_object_func, | |
74 | bt_ctf_object_pool_destroy_object_func destroy_object_func, | |
75 | void *data); | |
76 | ||
77 | /* | |
78 | * Finalizes an object pool without deallocating it. | |
79 | */ | |
80 | void bt_ctf_object_pool_finalize(struct bt_ctf_object_pool *pool); | |
81 | ||
82 | /* | |
83 | * Creates an object from an object pool. If the pool is empty, this | |
84 | * function calls the "new" user function to allocate a new object | |
85 | * before returning it. Otherwise this function returns a recycled | |
86 | * object, removing it from the pool. | |
87 | * | |
88 | * The returned object is owned by the caller. | |
89 | */ | |
90 | static inline | |
91 | void *bt_ctf_object_pool_create_object(struct bt_ctf_object_pool *pool) | |
92 | { | |
93 | struct bt_ctf_object *obj; | |
94 | ||
98b15851 | 95 | BT_ASSERT_DBG(pool); |
e1e02a22 | 96 | |
ef267d12 PP |
97 | #ifdef BT_LOGT |
98 | BT_LOGT("Creating object from pool: pool-addr=%p, pool-size=%zu, pool-cap=%u", | |
e1e02a22 PP |
99 | pool, pool->size, pool->objects->len); |
100 | #endif | |
101 | ||
102 | if (pool->size > 0) { | |
103 | /* Pick one from the pool */ | |
104 | pool->size--; | |
105 | obj = pool->objects->pdata[pool->size]; | |
106 | pool->objects->pdata[pool->size] = NULL; | |
107 | goto end; | |
108 | } | |
109 | ||
110 | /* Pool is empty: create a brand new object */ | |
ef267d12 PP |
111 | #ifdef BT_LOGT |
112 | BT_LOGT("Pool is empty: allocating new object: pool-addr=%p", | |
e1e02a22 PP |
113 | pool); |
114 | #endif | |
115 | ||
116 | obj = pool->funcs.new_object(pool->data); | |
117 | ||
118 | end: | |
ef267d12 PP |
119 | #ifdef BT_LOGT |
120 | BT_LOGT("Created one object from pool: pool-addr=%p, obj-addr=%p", | |
e1e02a22 PP |
121 | pool, obj); |
122 | #endif | |
123 | ||
124 | return obj; | |
125 | } | |
126 | ||
127 | /* | |
128 | * Recycles an object, that is, puts it back into the pool. | |
129 | * | |
130 | * The pool becomes the sole owner of the object to recycle. | |
131 | */ | |
132 | static inline | |
133 | void bt_ctf_object_pool_recycle_object(struct bt_ctf_object_pool *pool, void *obj) | |
134 | { | |
135 | struct bt_ctf_object *bt_obj = obj; | |
136 | ||
98b15851 PP |
137 | BT_ASSERT_DBG(pool); |
138 | BT_ASSERT_DBG(obj); | |
e1e02a22 | 139 | |
ef267d12 PP |
140 | #ifdef BT_LOGT |
141 | BT_LOGT("Recycling object: pool-addr=%p, pool-size=%zu, pool-cap=%u, obj-addr=%p", | |
e1e02a22 PP |
142 | pool, pool->size, pool->objects->len, obj); |
143 | #endif | |
144 | ||
145 | if (pool->size == pool->objects->len) { | |
146 | /* Backing array is full: make place for recycled object */ | |
ef267d12 PP |
147 | #ifdef BT_LOGT |
148 | BT_LOGT("Object pool is full: increasing object pool capacity: " | |
e1e02a22 PP |
149 | "pool-addr=%p, old-pool-cap=%u, new-pool-cap=%u", |
150 | pool, pool->objects->len, pool->objects->len + 1); | |
151 | #endif | |
152 | g_ptr_array_set_size(pool->objects, pool->size + 1); | |
153 | } | |
154 | ||
155 | /* Reset reference count to 1 since it could be 0 now */ | |
156 | bt_obj->ref_count = 1; | |
157 | ||
158 | /* Back to the pool */ | |
159 | pool->objects->pdata[pool->size] = obj; | |
160 | pool->size++; | |
161 | ||
ef267d12 PP |
162 | #ifdef BT_LOGT |
163 | BT_LOGT("Recycled object: pool-addr=%p, pool-size=%zu, pool-cap=%u, obj-addr=%p", | |
e1e02a22 PP |
164 | pool, pool->size, pool->objects->len, obj); |
165 | #endif | |
166 | } | |
167 | ||
168 | #endif /* BABELTRACE_CTF_WRITER_OBJECT_POOL_INTERNAL_H */ |