Function slab_map_lookup

src/foundation/slab_alloc.c:149–163

Lock-free. Returns the slab page whose base == (ptr & mask), or NULL if the * masked base is not a registered slab page (i.e. ptr is a plain heap block). */

/* Lock-free. Returns the slab page whose base == (ptr & mask), or NULL if the
 * masked base is not a registered slab page (i.e. ptr is a plain heap block). */
static slab_page_t *slab_map_lookup(uintptr_t base) {
    size_t i1, i2, i3;
    if (!slab_map_indices(base, &i1, &i2, &i3)) {
        return NULL;
    }
    slab_map_l2_t *l2 = atomic_load_explicit(&g_slab_map_root[i1], memory_order_acquire);
    if (!l2) {
        return NULL;
    }
    slab_map_l3_t *l3 = atomic_load_explicit(&l2->e[i2], memory_order_acquire);
    if (!l3) {
        return NULL;
    }
    return atomic_load_explicit(&l3->e[i3], memory_order_acquire);
}

/* Cold path. Sets the leaf entry for `base` to `val` (page to register, NULL to
 * unregister), allocating intermediate tables on demand. Returns false only if