1 #ifndef BABELTRACE_OBJECT_POOL_INTERNAL_H
2 #define BABELTRACE_OBJECT_POOL_INTERNAL_H
5 * Copyright (c) 2018 EfficiOS Inc. and Linux Foundation
6 * Copyright (c) 2018 Philippe Proulx <pproulx@efficios.com>
8 * Permission is hereby granted, free of charge, to any person obtaining a copy
9 * of this software and associated documentation files (the "Software"), to deal
10 * in the Software without restriction, including without limitation the rights
11 * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
12 * copies of the Software, and to permit persons to whom the Software is
13 * furnished to do so, subject to the following conditions:
15 * The above copyright notice and this permission notice shall be included in
16 * all copies or substantial portions of the Software.
18 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
19 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
20 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
21 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
22 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
23 * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
28 * This is a generic object pool to avoid memory allocation/deallocation
29 * for objects of which the lifespan is typically short, but which are
32 * The object pool, thanks to two user functions, knows how to allocate
33 * a brand new object in memory when the pool is empty and how to
34 * destroy an object when we destroy the pool.
36 * The object pool's user is responsible for:
38 * * Setting whatever references the object needs to keep and reset some
39 * properties _after_ calling bt_object_pool_create_object(). This is
40 * typically done in the bt_*_create() function which calls
41 * bt_object_pool_create_object() (which could call the user-provided
42 * allocation function if the pool is empty) and then sets the
43 * appropriate properties on the possibly recycled object.
45 * * Releasing whatever references the object keeps _before_ calling
46 * bt_object_pool_recycle_object(). This is typically done in a custom
47 * bt_*_recycle() function which does the necessary before calling
48 * bt_object_pool_recycle_object() with an object ready to be reused
53 #include <babeltrace/object-internal.h>
55 typedef void *(*bt_object_pool_new_object_func
)(void *data
);
56 typedef void *(*bt_object_pool_destroy_object_func
)(void *obj
, void *data
);
58 struct bt_object_pool
{
60 * Container of recycled objects, owned by this. The array's size
61 * is the pool's capacity.
66 * Pool's size, that is, number of elements in the array above,
67 * starting at index 0, which exist as recycled objects.
73 /* Allocate a new object in memory */
74 bt_object_pool_new_object_func new_object
;
76 /* Free direct and indirect memory occupied by object */
77 bt_object_pool_destroy_object_func destroy_object
;
80 /* User data passed to user functions */
85 * Initializes an object pool which is already allocated.
87 int bt_object_pool_initialize(struct bt_object_pool
*pool
,
88 bt_object_pool_new_object_func new_object_func
,
89 bt_object_pool_destroy_object_func destroy_object_func
,
93 * Finalizes an object pool without deallocating it.
95 void bt_object_pool_finalize(struct bt_object_pool
*pool
);
98 * Creates an object from an object pool. If the pool is empty, this
99 * function calls the "new" user function to allocate a new object
100 * before returning it. Otherwise this function returns a recycled
101 * object, removing it from the pool.
103 * The returned object is owned by the caller.
106 void *bt_object_pool_create_object(struct bt_object_pool
*pool
)
108 struct bt_object
*obj
;
113 BT_LOGV("Creating object from pool: pool-addr=%p, pool-size=%zu, pool-cap=%u",
114 pool
, pool
->size
, pool
->objects
->len
);
117 if (pool
->size
> 0) {
118 /* Pick one from the pool */
120 obj
= pool
->objects
->pdata
[pool
->size
];
121 pool
->objects
->pdata
[pool
->size
] = NULL
;
125 /* Pool is empty: create a brand new object */
127 BT_LOGV("Pool is empty: allocating new object: pool-addr=%p",
131 obj
= pool
->funcs
.new_object(pool
->data
);
135 BT_LOGV("Created one object from pool: pool-addr=%p, obj-addr=%p",
143 * Recycles an object, that is, puts it back into the pool.
145 * The pool becomes the sole owner of the object to recycle.
148 void bt_object_pool_recycle_object(struct bt_object_pool
*pool
, void *obj
)
150 struct bt_object
*bt_obj
= obj
;
156 BT_LOGV("Recycling object: pool-addr=%p, pool-size=%zu, pool-cap=%u, obj-addr=%p",
157 pool
, pool
->size
, pool
->objects
->len
, obj
);
160 if (pool
->size
== pool
->objects
->len
) {
161 /* Backing array is full: make place for recycled object */
163 BT_LOGV("Object pool is full: increasing object pool capacity: "
164 "pool-addr=%p, old-pool-cap=%u, new-pool-cap=%u",
165 pool
, pool
->objects
->len
, pool
->objects
->len
+ 1);
167 g_ptr_array_set_size(pool
->objects
, pool
->size
+ 1);
170 /* Reset reference count to 1 since it could be 0 now */
171 bt_obj
->ref_count
= 1;
173 /* Back to the pool */
174 pool
->objects
->pdata
[pool
->size
] = obj
;
178 BT_LOGV("Recycled object: pool-addr=%p, pool-size=%zu, pool-cap=%u, obj-addr=%p",
179 pool
, pool
->size
, pool
->objects
->len
, obj
);
183 #endif /* BABELTRACE_OBJECT_POOL_INTERNAL_H */