50     * - a pointer to the child pool to which this element belongs, or
64       /* Next page in the same child pool. */
85  * pool has been destroyed). Mark the element as freed and free the whole page
101  * Create a parent pool for the allocation of same-sized objects.
124  * Create a child pool linked to the given parent.
126 void slab_create_child(struct slab_child_pool *pool,  in slab_create_child()  argument
129    pool->parent = parent;  in slab_create_child()
130    pool->pages = NULL;  in slab_create_child()
131    pool->free = NULL;  in slab_create_child()
132    pool->migrated = NULL;  in slab_create_child()
136  * Destroy the child pool.
138  * Pages associated to the pool will be orphaned. They are eventually freed
141 void slab_destroy_child(struct slab_child_pool *pool)  in slab_destroy_child()  argument
143    if (!pool->parent)  in slab_destroy_child()
146    mtx_lock(&pool->parent->mutex);  in slab_destroy_child()
148    while (pool->pages) {  in slab_destroy_child()
149       struct slab_page_header *page = pool->pages;  in slab_destroy_child()
150       pool->pages = page->u.next;  in slab_destroy_child()
151       p_atomic_set(&page->u.num_remaining, pool->parent->num_elements);  in slab_destroy_child()
153       for (unsigned i = 0; i < pool->parent->num_elements; ++i) {  in slab_destroy_child()
154          struct slab_element_header *elt = slab_get_element(pool->parent, page, i);  in slab_destroy_child()
159    while (pool->migrated) {  in slab_destroy_child()
160       struct slab_element_header *elt = pool->migrated;  in slab_destroy_child()
161       pool->migrated = elt->next;  in slab_destroy_child()
165    mtx_unlock(&pool->parent->mutex);  in slab_destroy_child()
167    while (pool->free) {  in slab_destroy_child()
168       struct slab_element_header *elt = pool->free;  in slab_destroy_child()
169       pool->free = elt->next;  in slab_destroy_child()
174    pool->parent = NULL;  in slab_destroy_child()
178 slab_add_new_page(struct slab_child_pool *pool)  in slab_add_new_page()  argument
181       pool->parent->num_elements * pool->parent->element_size);  in slab_add_new_page()
186    for (unsigned i = 0; i < pool->parent->num_elements; ++i) {  in slab_add_new_page()
187       struct slab_element_header *elt = slab_get_element(pool->parent, page, i);  in slab_add_new_page()
188       elt->owner = (intptr_t)pool;  in slab_add_new_page()
191       elt->next = pool->free;  in slab_add_new_page()
192       pool->free = elt;  in slab_add_new_page()
196    page->u.next = pool->pages;  in slab_add_new_page()
197    pool->pages = page;  in slab_add_new_page()
203  * Allocate an object from the child pool. Single-threaded (i.e. the caller
204  * must ensure that no operation happens on the same child pool in another
208 slab_alloc(struct slab_child_pool *pool)  in slab_alloc()  argument
212    if (!pool->free) {  in slab_alloc()
214        * different child pool.  in slab_alloc()
216       mtx_lock(&pool->parent->mutex);  in slab_alloc()
217       pool->free = pool->migrated;  in slab_alloc()
218       pool->migrated = NULL;  in slab_alloc()
219       mtx_unlock(&pool->parent->mutex);  in slab_alloc()
222       if (!pool->free && !slab_add_new_page(pool))  in slab_alloc()
226    elt = pool->free;  in slab_alloc()
227    pool->free = elt->next;  in slab_alloc()
237  * must ensure that no operation happens on the same child pool in another
240  * Freeing an object in a different child pool from the one where it was
241  * allocated is allowed, as long the pool belong to the same parent. No
244 void slab_free(struct slab_child_pool *pool, void *ptr)  in slab_free()  argument
252    if (p_atomic_read(&elt->owner) == (intptr_t)pool) {  in slab_free()
256       elt->next = pool->free;  in slab_free()
257       pool->free = elt;  in slab_free()
262    mtx_lock(&pool->parent->mutex);  in slab_free()
264    /* Note: we _must_ re-read elt->owner here because the owning child pool  in slab_free()
273       mtx_unlock(&pool->parent->mutex);  in slab_free()
275       mtx_unlock(&pool->parent->mutex);  in slab_free()
285 slab_alloc_st(struct slab_mempool *pool)  in slab_alloc_st()  argument
287    return slab_alloc(&pool->child);  in slab_alloc_st()
294 slab_free_st(struct slab_mempool *pool, void *ptr)  in slab_free_st()  argument
296    slab_free(&pool->child, ptr);  in slab_free_st()
300 slab_destroy(struct slab_mempool *pool)  in slab_destroy()  argument
302    slab_destroy_child(&pool->child);  in slab_destroy()
303    slab_destroy_parent(&pool->parent);  in slab_destroy()
313 slab_create(struct slab_mempool *pool,  in slab_create()  argument
317    slab_create_parent(&pool->parent, item_size, num_items);  in slab_create()
318    slab_create_child(&pool->child, &pool->parent);  in slab_create()