48     * - a pointer to the child pool to which this element belongs, or
62       /* Next page in the same child pool. */
83  * pool has been destroyed). Mark the element as freed and free the whole page
99  * Create a parent pool for the allocation of same-sized objects.
122  * Create a child pool linked to the given parent.
124 void slab_create_child(struct slab_child_pool *pool,  in slab_create_child()  argument
127    pool->parent = parent;  in slab_create_child()
128    pool->pages = NULL;  in slab_create_child()
129    pool->free = NULL;  in slab_create_child()
130    pool->migrated = NULL;  in slab_create_child()
134  * Destroy the child pool.
136  * Pages associated to the pool will be orphaned. They are eventually freed
139 void slab_destroy_child(struct slab_child_pool *pool)  in slab_destroy_child()  argument
141    if (!pool->parent)  in slab_destroy_child()
144    simple_mtx_lock(&pool->parent->mutex);  in slab_destroy_child()
146    while (pool->pages) {  in slab_destroy_child()
147       struct slab_page_header *page = pool->pages;  in slab_destroy_child()
148       pool->pages = page->u.next;  in slab_destroy_child()
149       p_atomic_set(&page->u.num_remaining, pool->parent->num_elements);  in slab_destroy_child()
151       for (unsigned i = 0; i < pool->parent->num_elements; ++i) {  in slab_destroy_child()
152          struct slab_element_header *elt = slab_get_element(pool->parent, page, i);  in slab_destroy_child()
157    while (pool->migrated) {  in slab_destroy_child()
158       struct slab_element_header *elt = pool->migrated;  in slab_destroy_child()
159       pool->migrated = elt->next;  in slab_destroy_child()
163    simple_mtx_unlock(&pool->parent->mutex);  in slab_destroy_child()
165    while (pool->free) {  in slab_destroy_child()
166       struct slab_element_header *elt = pool->free;  in slab_destroy_child()
167       pool->free = elt->next;  in slab_destroy_child()
172    pool->parent = NULL;  in slab_destroy_child()
176 slab_add_new_page(struct slab_child_pool *pool)  in slab_add_new_page()  argument
179       pool->parent->num_elements * pool->parent->element_size);  in slab_add_new_page()
184    for (unsigned i = 0; i < pool->parent->num_elements; ++i) {  in slab_add_new_page()
185       struct slab_element_header *elt = slab_get_element(pool->parent, page, i);  in slab_add_new_page()
186       elt->owner = (intptr_t)pool;  in slab_add_new_page()
189       elt->next = pool->free;  in slab_add_new_page()
190       pool->free = elt;  in slab_add_new_page()
194    page->u.next = pool->pages;  in slab_add_new_page()
195    pool->pages = page;  in slab_add_new_page()
201  * Allocate an object from the child pool. Single-threaded (i.e. the caller
202  * must ensure that no operation happens on the same child pool in another
206 slab_alloc(struct slab_child_pool *pool)  in slab_alloc()  argument
210    if (!pool->free) {  in slab_alloc()
212        * different child pool.  in slab_alloc()
214       simple_mtx_lock(&pool->parent->mutex);  in slab_alloc()
215       pool->free = pool->migrated;  in slab_alloc()
216       pool->migrated = NULL;  in slab_alloc()
217       simple_mtx_unlock(&pool->parent->mutex);  in slab_alloc()
220       if (!pool->free && !slab_add_new_page(pool))  in slab_alloc()
224    elt = pool->free;  in slab_alloc()
225    pool->free = elt->next;  in slab_alloc()
235  * must ensure that no operation happens on the same child pool in another
238  * Freeing an object in a different child pool from the one where it was
239  * allocated is allowed, as long the pool belong to the same parent. No
242 void slab_free(struct slab_child_pool *pool, void *ptr)  in slab_free()  argument
250    if (p_atomic_read(&elt->owner) == (intptr_t)pool) {  in slab_free()
254       elt->next = pool->free;  in slab_free()
255       pool->free = elt;  in slab_free()
260    if (pool->parent)  in slab_free()
261       simple_mtx_lock(&pool->parent->mutex);  in slab_free()
263    /* Note: we _must_ re-read elt->owner here because the owning child pool  in slab_free()
272       if (pool->parent)  in slab_free()
273          simple_mtx_unlock(&pool->parent->mutex);  in slab_free()
275       if (pool->parent)  in slab_free()
276          simple_mtx_unlock(&pool->parent->mutex);  in slab_free()