Function base_extent_alloc

deps/jemalloc/src/base.c:307–342

* Allocate an extent that is at least as large as specified size, with * specified alignment. */

 * specified alignment.
 */
static extent_t *
base_extent_alloc(tsdn_t *tsdn, base_t *base, size_t size, size_t alignment) {
	malloc_mutex_assert_owner(tsdn, &base->mtx);

	extent_hooks_t *extent_hooks = base_extent_hooks_get(base);
	/*
	 * Drop mutex during base_block_alloc(), because an extent hook will be
	 * called.
	 */
	malloc_mutex_unlock(tsdn, &base->mtx);
	base_block_t *block = base_block_alloc(tsdn, base, extent_hooks,
	    base_ind_get(base), &base->pind_last, &base->extent_sn_next, size,
	    alignment);
	malloc_mutex_lock(tsdn, &base->mtx);
	if (block == NULL) {
		return NULL;
	}
	block->next = base->blocks;
	base->blocks = block;
	if (config_stats) {
		base->allocated += sizeof(base_block_t);
		base->resident += PAGE_CEILING(sizeof(base_block_t));
		base->mapped += block->size;
		if (metadata_thp_madvise() &&
		    !(opt_metadata_thp == metadata_thp_auto
		      && !base->auto_thp_switched)) {
			assert(base->n_thp > 0);
			base->n_thp += HUGEPAGE_CEILING(sizeof(base_block_t)) >>
			    LG_HUGEPAGE;
		}
		assert(base->allocated <= base->resident);
		assert(base->resident <= base->mapped);
		assert(base->n_thp << LG_HUGEPAGE <= base->mapped);
	}
	return &block->extent;
}

base_t *
b0get(void) {