Function mi_os_alloc_huge_os_pagesx

3rd/mimalloc-2.0.9/src/os.c:1157–1198

#if defined(_WIN32) && (MI_INTPTR_SIZE >= 8)
static void* mi_os_alloc_huge_os_pagesx(void* addr, size_t size, int numa_node)
{
  mi_assert_internal(size%MI_GiB == 0);
  mi_assert_internal(addr != NULL);
  const DWORD flags = MEM_LARGE_PAGES | MEM_COMMIT | MEM_RESERVE;

  mi_win_enable_large_os_pages();

  MI_MEM_EXTENDED_PARAMETER params[3] = { {{0,0},{0}},{{0,0},{0}},{{0,0},{0}} };
  // on modern Windows try use NtAllocateVirtualMemoryEx for 1GiB huge pages
  static bool mi_huge_pages_available = true;
  if (pNtAllocateVirtualMemoryEx != NULL && mi_huge_pages_available) {
    params[0].Type.Type = MiMemExtendedParameterAttributeFlags;
    params[0].Arg.ULong64 = MI_MEM_EXTENDED_PARAMETER_NONPAGED_HUGE;
    ULONG param_count = 1;
    if (numa_node >= 0) {
      param_count++;
      params[1].Type.Type = MiMemExtendedParameterNumaNode;
      params[1].Arg.ULong = (unsigned)numa_node;
    }
    SIZE_T psize = size;
    void* base = addr;
    NTSTATUS err = (*pNtAllocateVirtualMemoryEx)(GetCurrentProcess(), &base, &psize, flags, PAGE_READWRITE, params, param_count);
    if (err == 0 && base != NULL) {
      return base;
    }
    else {
      // fall back to regular large pages
      mi_huge_pages_available = false; // don't try further huge pages
      _mi_warning_message("unable to allocate using huge (1GiB) pages, trying large (2MiB) pages instead (status 0x%lx)\n", err);
    }
  }
  // on modern Windows try use VirtualAlloc2 for numa aware large OS page allocation
  if (pVirtualAlloc2 != NULL && numa_node >= 0) {
    params[0].Type.Type = MiMemExtendedParameterNumaNode;
    params[0].Arg.ULong = (unsigned)numa_node;
    return (*pVirtualAlloc2)(GetCurrentProcess(), addr, size, flags, PAGE_READWRITE, params, 1);
  }

  // otherwise use regular virtual alloc on older windows
  return VirtualAlloc(addr, size, flags, PAGE_READWRITE);
}

#elif defined(MI_OS_USE_MMAP) && (MI_INTPTR_SIZE >= 8) && !defined(__HAIKU__)
#include <sys/syscall.h>