pp->n_free_blocks = 1 << (pm->def_log2_page_sz - PMALLOC_LOG2_BLOCK_SZ);
pp->index = pp - pm->pages;
pp->arena_index = a->index;
pp->n_free_blocks = 1 << (pm->def_log2_page_sz - PMALLOC_LOG2_BLOCK_SZ);
pp->index = pp - pm->pages;
pp->arena_index = a->index;