Function mi_arena_allocate

3rd/mimalloc-2.0.9/src/arena.c:194–246

allocate from an arena with fallback to the OS

// allocate from an arena with fallback to the OS
static mi_decl_noinline void* mi_arena_allocate(int numa_node, size_t size, size_t alignment, bool* commit, bool* large,
                                                bool* is_pinned, bool* is_zero,
                                                mi_arena_id_t req_arena_id, size_t* memid, mi_os_tld_t* tld )
{
  MI_UNUSED_RELEASE(alignment);
  mi_assert_internal(alignment <= MI_SEGMENT_ALIGN);
  const size_t max_arena = mi_atomic_load_relaxed(&mi_arena_count);
  const size_t bcount = mi_block_count_of_size(size);
  if mi_likely(max_arena == 0) return NULL;
  mi_assert_internal(size <= bcount * MI_ARENA_BLOCK_SIZE);

  size_t arena_index = mi_arena_id_index(req_arena_id);
  if (arena_index < MI_MAX_ARENAS) {
    // try a specific arena if requested
    mi_arena_t* arena = mi_atomic_load_ptr_relaxed(mi_arena_t, &mi_arenas[arena_index]);
    if ((arena != NULL) &&
        (arena->numa_node < 0 || arena->numa_node == numa_node) && // numa local?
        (*large || !arena->is_large)) // large OS pages allowed, or arena is not large OS pages
    {
      void* p = mi_arena_alloc_from(arena, arena_index, bcount, commit, large, is_pinned, is_zero, req_arena_id, memid, tld);
      mi_assert_internal((uintptr_t)p % alignment == 0);
      if (p != NULL) return p;
    }
  }
  else {
    // try numa affine allocation
    for (size_t i = 0; i < max_arena; i++) {
      mi_arena_t* arena = mi_atomic_load_ptr_relaxed(mi_arena_t, &mi_arenas[i]);
      if (arena == NULL) break; // end reached
      if ((arena->numa_node < 0 || arena->numa_node == numa_node) && // numa local?
          (*large || !arena->is_large)) // large OS pages allowed, or arena is not large OS pages
      {
        void* p = mi_arena_alloc_from(arena, i, bcount, commit, large, is_pinned, is_zero, req_arena_id, memid, tld);
        mi_assert_internal((uintptr_t)p % alignment == 0);
        if (p != NULL) return p;
      }
    }

    // try from another numa node instead..
    for (size_t i = 0; i < max_arena; i++) {
      mi_arena_t* arena = mi_atomic_load_ptr_relaxed(mi_arena_t, &mi_arenas[i]);
      if (arena == NULL) break; // end reached
      if ((arena->numa_node >= 0 && arena->numa_node != numa_node) && // not numa local!
          (*large || !arena->is_large)) // large OS pages allowed, or arena is not large OS pages
      {
        void* p = mi_arena_alloc_from(arena, i, bcount, commit, large, is_pinned, is_zero, req_arena_id, memid, tld);
        mi_assert_internal((uintptr_t)p % alignment == 0);
        if (p != NULL) return p;
      }
    }
  }
  return NULL;
}

void* _mi_arena_alloc_aligned(size_t size, size_t alignment, size_t align_offset, bool* commit, bool* large, bool* is_pinned, bool* is_zero,
                              mi_arena_id_t req_arena_id, size_t* memid, mi_os_tld_t* tld)