1 files changed, 1232 insertions, 0 deletions

diff --git a/contrib/libs/mimalloc/src/os.c b/contrib/libs/mimalloc/src/os.c
new file mode 100644
index 00000000000..85415232d7b
--- /dev/null
+++ b/contrib/libs/mimalloc/src/os.c
@@ -0,0 +1,1232 @@
+/* ----------------------------------------------------------------------------
+Copyright (c) 2018-2021, Microsoft Research, Daan Leijen
+This is free software; you can redistribute it and/or modify it under the
+terms of the MIT license. A copy of the license can be found in the file
+"LICENSE" at the root of this distribution.
+-----------------------------------------------------------------------------*/
+#ifndef _DEFAULT_SOURCE
+#define _DEFAULT_SOURCE   // ensure mmap flags are defined
+#endif
+
+#if defined(__sun)
+// illumos provides new mman.h api when any of these are defined
+// otherwise the old api based on caddr_t which predates the void pointers one.
+// stock solaris provides only the former, chose to atomically to discard those
+// flags only here rather than project wide tough.
+#undef _XOPEN_SOURCE
+#undef _POSIX_C_SOURCE
+#endif
+#include "mimalloc.h"
+#include "mimalloc-internal.h"
+#include "mimalloc-atomic.h"
+
+#include <string.h>  // strerror
+
+#ifdef _MSC_VER
+#pragma warning(disable:4996)  // strerror
+#endif
+
+
+#if defined(_WIN32)
+#include <windows.h>
+#elif defined(__wasi__)
+// stdlib.h is all we need, and has already been included in mimalloc.h
+#else
+#include <sys/mman.h>  // mmap
+#include <unistd.h>    // sysconf
+#if defined(__linux__)
+#include <features.h>
+#if defined(__GLIBC__)
+#include <linux/mman.h> // linux mmap flags
+#else
+#include <sys/mman.h>
+#endif
+#endif
+#if defined(__APPLE__)
+#include <TargetConditionals.h>
+#if !TARGET_IOS_IPHONE && !TARGET_IOS_SIMULATOR
+#include <mach/vm_statistics.h>
+#endif
+#endif
+#if defined(__HAIKU__)
+#define madvise posix_madvise
+#define MADV_DONTNEED POSIX_MADV_DONTNEED
+#endif
+#endif
+
+/* -----------------------------------------------------------
+  Initialization.
+  On windows initializes support for aligned allocation and
+  large OS pages (if MIMALLOC_LARGE_OS_PAGES is true).
+----------------------------------------------------------- */
+bool    _mi_os_decommit(void* addr, size_t size, mi_stats_t* stats);
+
+static void* mi_align_up_ptr(void* p, size_t alignment) {
+  return (void*)_mi_align_up((uintptr_t)p, alignment);
+}
+
+static inline uintptr_t _mi_align_down(uintptr_t sz, size_t alignment) {
+  mi_assert_internal(alignment != 0);
+  uintptr_t mask = alignment - 1;
+  if ((alignment & mask) == 0) { // power of two?
+    return (sz & ~mask);
+  }
+  else {
+    return ((sz / alignment) * alignment);
+  }
+}
+
+static void* mi_align_down_ptr(void* p, size_t alignment) {
+  return (void*)_mi_align_down((uintptr_t)p, alignment);
+}
+
+// page size (initialized properly in `os_init`)
+static size_t os_page_size = 4096;
+
+// minimal allocation granularity
+static size_t os_alloc_granularity = 4096;
+
+// if non-zero, use large page allocation
+static size_t large_os_page_size = 0;
+
+// OS (small) page size
+size_t _mi_os_page_size() {
+  return os_page_size;
+}
+
+// if large OS pages are supported (2 or 4MiB), then return the size, otherwise return the small page size (4KiB)
+size_t _mi_os_large_page_size() {
+  return (large_os_page_size != 0 ? large_os_page_size : _mi_os_page_size());
+}
+
+static bool use_large_os_page(size_t size, size_t alignment) {
+  // if we have access, check the size and alignment requirements
+  if (large_os_page_size == 0 || !mi_option_is_enabled(mi_option_large_os_pages)) return false;
+  return ((size % large_os_page_size) == 0 && (alignment % large_os_page_size) == 0);
+}
+
+// round to a good OS allocation size (bounded by max 12.5% waste)
+size_t _mi_os_good_alloc_size(size_t size) {
+  size_t align_size;
+  if (size < 512*KiB) align_size = _mi_os_page_size();
+  else if (size < 2*MiB) align_size = 64*KiB;
+  else if (size < 8*MiB) align_size = 256*KiB;
+  else if (size < 32*MiB) align_size = 1*MiB;
+  else align_size = 4*MiB;
+  if (mi_unlikely(size >= (SIZE_MAX - align_size))) return size; // possible overflow?
+  return _mi_align_up(size, align_size);
+}
+
+#if defined(_WIN32)
+// We use VirtualAlloc2 for aligned allocation, but it is only supported on Windows 10 and Windows Server 2016.
+// So, we need to look it up dynamically to run on older systems. (use __stdcall for 32-bit compatibility)
+// NtAllocateVirtualAllocEx is used for huge OS page allocation (1GiB)
+//
+// We hide MEM_EXTENDED_PARAMETER to compile with older SDK's.
+#include <winternl.h>
+typedef PVOID    (__stdcall *PVirtualAlloc2)(HANDLE, PVOID, SIZE_T, ULONG, ULONG, /* MEM_EXTENDED_PARAMETER* */ void*, ULONG);
+typedef NTSTATUS (__stdcall *PNtAllocateVirtualMemoryEx)(HANDLE, PVOID*, SIZE_T*, ULONG, ULONG, /* MEM_EXTENDED_PARAMETER* */ PVOID, ULONG);
+static PVirtualAlloc2 pVirtualAlloc2 = NULL;
+static PNtAllocateVirtualMemoryEx pNtAllocateVirtualMemoryEx = NULL;
+
+// Similarly, GetNumaProcesorNodeEx is only supported since Windows 7
+#if (_WIN32_WINNT < 0x601)  // before Win7
+typedef struct _PROCESSOR_NUMBER { WORD Group; BYTE Number; BYTE Reserved; } PROCESSOR_NUMBER, *PPROCESSOR_NUMBER;
+#endif
+typedef VOID (__stdcall *PGetCurrentProcessorNumberEx)(PPROCESSOR_NUMBER ProcNumber);
+typedef BOOL (__stdcall *PGetNumaProcessorNodeEx)(PPROCESSOR_NUMBER Processor, PUSHORT NodeNumber);
+typedef BOOL (__stdcall* PGetNumaNodeProcessorMaskEx)(USHORT Node, PGROUP_AFFINITY ProcessorMask);
+static PGetCurrentProcessorNumberEx pGetCurrentProcessorNumberEx = NULL;
+static PGetNumaProcessorNodeEx      pGetNumaProcessorNodeEx = NULL;
+static PGetNumaNodeProcessorMaskEx  pGetNumaNodeProcessorMaskEx = NULL;
+
+static bool mi_win_enable_large_os_pages()
+{
+  if (large_os_page_size > 0) return true;
+
+  // Try to see if large OS pages are supported
+  // To use large pages on Windows, we first need access permission
+  // Set "Lock pages in memory" permission in the group policy editor
+  // <https://devblogs.microsoft.com/oldnewthing/20110128-00/?p=11643>
+  unsigned long err = 0;
+  HANDLE token = NULL;
+  BOOL ok = OpenProcessToken(GetCurrentProcess(), TOKEN_ADJUST_PRIVILEGES | TOKEN_QUERY, &token);
+  if (ok) {
+    TOKEN_PRIVILEGES tp;
+    ok = LookupPrivilegeValue(NULL, TEXT("SeLockMemoryPrivilege"), &tp.Privileges[0].Luid);
+    if (ok) {
+      tp.PrivilegeCount = 1;
+      tp.Privileges[0].Attributes = SE_PRIVILEGE_ENABLED;
+      ok = AdjustTokenPrivileges(token, FALSE, &tp, 0, (PTOKEN_PRIVILEGES)NULL, 0);
+      if (ok) {
+        err = GetLastError();
+        ok = (err == ERROR_SUCCESS);
+        if (ok) {
+          large_os_page_size = GetLargePageMinimum();
+        }
+      }
+    }
+    CloseHandle(token);
+  }
+  if (!ok) {
+    if (err == 0) err = GetLastError();
+    _mi_warning_message("cannot enable large OS page support, error %lu\n", err);
+  }
+  return (ok!=0);
+}
+
+void _mi_os_init(void) {
+  // get the page size
+  SYSTEM_INFO si;
+  GetSystemInfo(&si);
+  if (si.dwPageSize > 0) os_page_size = si.dwPageSize;
+  if (si.dwAllocationGranularity > 0) os_alloc_granularity = si.dwAllocationGranularity;
+  // get the VirtualAlloc2 function
+  HINSTANCE  hDll;
+  hDll = LoadLibrary(TEXT("kernelbase.dll"));
+  if (hDll != NULL) {
+    // use VirtualAlloc2FromApp if possible as it is available to Windows store apps
+    pVirtualAlloc2 = (PVirtualAlloc2)(void (*)(void))GetProcAddress(hDll, "VirtualAlloc2FromApp");
+    if (pVirtualAlloc2==NULL) pVirtualAlloc2 = (PVirtualAlloc2)(void (*)(void))GetProcAddress(hDll, "VirtualAlloc2");
+    FreeLibrary(hDll);
+  }
+  // NtAllocateVirtualMemoryEx is used for huge page allocation
+  hDll = LoadLibrary(TEXT("ntdll.dll"));
+  if (hDll != NULL) {
+    pNtAllocateVirtualMemoryEx = (PNtAllocateVirtualMemoryEx)(void (*)(void))GetProcAddress(hDll, "NtAllocateVirtualMemoryEx");
+    FreeLibrary(hDll);
+  }
+  // Try to use Win7+ numa API
+  hDll = LoadLibrary(TEXT("kernel32.dll"));
+  if (hDll != NULL) {
+    pGetCurrentProcessorNumberEx = (PGetCurrentProcessorNumberEx)(void (*)(void))GetProcAddress(hDll, "GetCurrentProcessorNumberEx");
+    pGetNumaProcessorNodeEx = (PGetNumaProcessorNodeEx)(void (*)(void))GetProcAddress(hDll, "GetNumaProcessorNodeEx");
+    pGetNumaNodeProcessorMaskEx = (PGetNumaNodeProcessorMaskEx)(void (*)(void))GetProcAddress(hDll, "GetNumaNodeProcessorMaskEx");
+    FreeLibrary(hDll);
+  }
+  if (mi_option_is_enabled(mi_option_large_os_pages) || mi_option_is_enabled(mi_option_reserve_huge_os_pages)) {
+    mi_win_enable_large_os_pages();
+  }
+}
+#elif defined(__wasi__)
+void _mi_os_init() {
+  os_page_size = 0x10000; // WebAssembly has a fixed page size: 64KB
+  os_alloc_granularity = 16;
+}
+#else
+void _mi_os_init() {
+  // get the page size
+  long result = sysconf(_SC_PAGESIZE);
+  if (result > 0) {
+    os_page_size = (size_t)result;
+    os_alloc_granularity = os_page_size;
+  }
+  large_os_page_size = 2*MiB; // TODO: can we query the OS for this?
+}
+#endif
+
+
+/* -----------------------------------------------------------
+  Raw allocation on Windows (VirtualAlloc) and Unix's (mmap).
+----------------------------------------------------------- */
+
+static bool mi_os_mem_free(void* addr, size_t size, bool was_committed, mi_stats_t* stats)
+{
+  if (addr == NULL || size == 0) return true; // || _mi_os_is_huge_reserved(addr)
+  bool err = false;
+#if defined(_WIN32)
+  err = (VirtualFree(addr, 0, MEM_RELEASE) == 0);
+#elif defined(__wasi__)
+  err = 0; // WebAssembly's heap cannot be shrunk
+#else
+  err = (munmap(addr, size) == -1);
+#endif
+  if (was_committed) _mi_stat_decrease(&stats->committed, size);
+  _mi_stat_decrease(&stats->reserved, size);
+  if (err) {
+    _mi_warning_message("munmap failed: %s, addr 0x%8li, size %lu\n", strerror(errno), (size_t)addr, size);
+    return false;
+  }
+  else {
+    return true;
+  }
+}
+
+static void* mi_os_get_aligned_hint(size_t try_alignment, size_t size);
+
+#ifdef _WIN32
+static void* mi_win_virtual_allocx(void* addr, size_t size, size_t try_alignment, DWORD flags) {
+#if (MI_INTPTR_SIZE >= 8)
+  // on 64-bit systems, try to use the virtual address area after 4TiB for 4MiB aligned allocations
+  void* hint;
+  if (addr == NULL && (hint = mi_os_get_aligned_hint(try_alignment,size)) != NULL) {
+    void* p = VirtualAlloc(hint, size, flags, PAGE_READWRITE);
+    if (p != NULL) return p;
+    DWORD err = GetLastError();
+    if (err != ERROR_INVALID_ADDRESS &&   // If linked with multiple instances, we may have tried to allocate at an already allocated area (#210)
+        err != ERROR_INVALID_PARAMETER) { // Windows7 instability (#230)
+      return NULL;
+    }
+    // fall through
+  } 
+#endif
+#if defined(MEM_EXTENDED_PARAMETER_TYPE_BITS)
+  // on modern Windows try use VirtualAlloc2 for aligned allocation
+  if (try_alignment > 0 && (try_alignment % _mi_os_page_size()) == 0 && pVirtualAlloc2 != NULL) {
+    MEM_ADDRESS_REQUIREMENTS reqs = { 0, 0, 0 };
+    reqs.Alignment = try_alignment;
+    MEM_EXTENDED_PARAMETER param = { {0, 0}, {0} };
+    param.Type = MemExtendedParameterAddressRequirements;
+    param.Pointer = &reqs;
+    return (*pVirtualAlloc2)(GetCurrentProcess(), addr, size, flags, PAGE_READWRITE, &param, 1);
+  }
+#endif
+  // last resort
+  return VirtualAlloc(addr, size, flags, PAGE_READWRITE);
+}
+
+static void* mi_win_virtual_alloc(void* addr, size_t size, size_t try_alignment, DWORD flags, bool large_only, bool allow_large, bool* is_large) {
+  mi_assert_internal(!(large_only && !allow_large));
+  static _Atomic(uintptr_t) large_page_try_ok; // = 0;
+  void* p = NULL;
+  if ((large_only || use_large_os_page(size, try_alignment))
+      && allow_large && (flags&MEM_COMMIT)!=0 && (flags&MEM_RESERVE)!=0) {
+    uintptr_t try_ok = mi_atomic_load_acquire(&large_page_try_ok);
+    if (!large_only && try_ok > 0) {
+      // if a large page allocation fails, it seems the calls to VirtualAlloc get very expensive.
+      // therefore, once a large page allocation failed, we don't try again for `large_page_try_ok` times.
+      mi_atomic_cas_strong_acq_rel(&large_page_try_ok, &try_ok, try_ok - 1);
+    }
+    else {
+      // large OS pages must always reserve and commit.
+      *is_large = true;
+      p = mi_win_virtual_allocx(addr, size, try_alignment, flags | MEM_LARGE_PAGES);
+      if (large_only) return p;
+      // fall back to non-large page allocation on error (`p == NULL`).
+      if (p == NULL) {
+        mi_atomic_store_release(&large_page_try_ok,10UL);  // on error, don't try again for the next N allocations
+      }
+    }
+  }
+  if (p == NULL) {
+    *is_large = ((flags&MEM_LARGE_PAGES) != 0);
+    p = mi_win_virtual_allocx(addr, size, try_alignment, flags);
+  }
+  if (p == NULL) {
+    _mi_warning_message("unable to allocate OS memory (%zu bytes, error code: %i, address: %p, large only: %d, allow large: %d)\n", size, GetLastError(), addr, large_only, allow_large);
+  }
+  return p;
+}
+
+#elif defined(__wasi__)
+static void* mi_wasm_heap_grow(size_t size, size_t try_alignment) {
+  uintptr_t base = __builtin_wasm_memory_size(0) * _mi_os_page_size();
+  uintptr_t aligned_base = _mi_align_up(base, (uintptr_t) try_alignment);
+  size_t alloc_size = _mi_align_up( aligned_base - base + size, _mi_os_page_size());
+  mi_assert(alloc_size >= size && (alloc_size % _mi_os_page_size()) == 0);
+  if (alloc_size < size) return NULL;
+  if (__builtin_wasm_memory_grow(0, alloc_size / _mi_os_page_size()) == SIZE_MAX) {
+    errno = ENOMEM;
+    return NULL;
+  }
+  return (void*)aligned_base;
+}
+#else
+#define MI_OS_USE_MMAP
+static void* mi_unix_mmapx(void* addr, size_t size, size_t try_alignment, int protect_flags, int flags, int fd) {
+  void* p = NULL;
+  #if (MI_INTPTR_SIZE >= 8) && !defined(MAP_ALIGNED)
+  // on 64-bit systems, use the virtual address area after 4TiB for 4MiB aligned allocations
+  void* hint;
+  if (addr == NULL && (hint = mi_os_get_aligned_hint(try_alignment, size)) != NULL) {
+    p = mmap(hint,size,protect_flags,flags,fd,0);
+    if (p==MAP_FAILED) p = NULL; // fall back to regular mmap
+  }
+  #else
+  UNUSED(try_alignment);
+  UNUSED(mi_os_get_aligned_hint);
+  #endif
+  if (p==NULL) {
+    p = mmap(addr,size,protect_flags,flags,fd,0);
+    if (p==MAP_FAILED) p = NULL;
+  }
+  return p;
+}
+
+static void* mi_unix_mmap(void* addr, size_t size, size_t try_alignment, int protect_flags, bool large_only, bool allow_large, bool* is_large) {
+  void* p = NULL;
+  #if !defined(MAP_ANONYMOUS)
+  #define MAP_ANONYMOUS  MAP_ANON
+  #endif
+  #if !defined(MAP_NORESERVE)
+  #define MAP_NORESERVE  0
+  #endif
+  int flags = MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE;
+  int fd = -1;
+  #if defined(MAP_ALIGNED)  // BSD
+  if (try_alignment > 0) {
+    size_t n = mi_bsr(try_alignment);
+    if (((size_t)1 << n) == try_alignment && n >= 12 && n <= 30) {  // alignment is a power of 2 and 4096 <= alignment <= 1GiB
+      flags |= MAP_ALIGNED(n);
+    }
+  }
+  #endif
+  #if defined(PROT_MAX)
+  protect_flags |= PROT_MAX(PROT_READ | PROT_WRITE); // BSD
+  #endif
+  #if defined(VM_MAKE_TAG)
+  // macOS: tracking anonymous page with a specific ID. (All up to 98 are taken officially but LLVM sanitizers had taken 99)
+  int os_tag = (int)mi_option_get(mi_option_os_tag);
+  if (os_tag < 100 || os_tag > 255) os_tag = 100;
+  fd = VM_MAKE_TAG(os_tag);
+  #endif
+  if ((large_only || use_large_os_page(size, try_alignment)) && allow_large) {
+    static _Atomic(uintptr_t) large_page_try_ok; // = 0;
+    uintptr_t try_ok = mi_atomic_load_acquire(&large_page_try_ok);
+    if (!large_only && try_ok > 0) {
+      // If the OS is not configured for large OS pages, or the user does not have
+      // enough permission, the `mmap` will always fail (but it might also fail for other reasons).
+      // Therefore, once a large page allocation failed, we don't try again for `large_page_try_ok` times
+      // to avoid too many failing calls to mmap.
+      mi_atomic_cas_strong_acq_rel(&large_page_try_ok, &try_ok, try_ok - 1);
+    }
+    else {
+      int lflags = flags & ~MAP_NORESERVE;  // using NORESERVE on huge pages seems to fail on Linux
+      int lfd = fd;
+      #ifdef MAP_ALIGNED_SUPER
+      lflags |= MAP_ALIGNED_SUPER;
+      #endif
+      #ifdef MAP_HUGETLB
+      lflags |= MAP_HUGETLB;
+      #endif
+      #ifdef MAP_HUGE_1GB
+      static bool mi_huge_pages_available = true;
+      if ((size % GiB) == 0 && mi_huge_pages_available) {
+        lflags |= MAP_HUGE_1GB;
+      }
+      else
+      #endif
+      {
+        #ifdef MAP_HUGE_2MB
+        lflags |= MAP_HUGE_2MB;
+        #endif
+      }
+      #ifdef VM_FLAGS_SUPERPAGE_SIZE_2MB
+      lfd |= VM_FLAGS_SUPERPAGE_SIZE_2MB;
+      #endif
+      if (large_only || lflags != flags) {
+        // try large OS page allocation
+        *is_large = true;
+        p = mi_unix_mmapx(addr, size, try_alignment, protect_flags, lflags, lfd);
+        #ifdef MAP_HUGE_1GB
+        if (p == NULL && (lflags & MAP_HUGE_1GB) != 0) {
+          mi_huge_pages_available = false; // don't try huge 1GiB pages again
+          _mi_warning_message("unable to allocate huge (1GiB) page, trying large (2MiB) pages instead (error %i)\n", errno);
+          lflags = ((lflags & ~MAP_HUGE_1GB) | MAP_HUGE_2MB);
+          p = mi_unix_mmapx(addr, size, try_alignment, protect_flags, lflags, lfd);
+        }
+        #endif
+        if (large_only) return p;
+        if (p == NULL) {
+          mi_atomic_store_release(&large_page_try_ok, (uintptr_t)10);  // on error, don't try again for the next N allocations
+        }
+      }
+    }
+  }
+  if (p == NULL) {
+    *is_large = false;
+    p = mi_unix_mmapx(addr, size, try_alignment, protect_flags, flags, fd);
+    #if defined(MADV_HUGEPAGE)
+    // Many Linux systems don't allow MAP_HUGETLB but they support instead
+    // transparent huge pages (THP). It is not required to call `madvise` with MADV_HUGE
+    // though since properly aligned allocations will already use large pages if available
+    // in that case -- in particular for our large regions (in `memory.c`).
+    // However, some systems only allow THP if called with explicit `madvise`, so
+    // when large OS pages are enabled for mimalloc, we call `madvise` anyways.
+    if (allow_large && use_large_os_page(size, try_alignment)) {
+      if (madvise(p, size, MADV_HUGEPAGE) == 0) {
+        *is_large = true; // possibly
+      };
+    }
+    #endif
+    #if defined(__sun)
+    if (allow_large && use_large_os_page(size, try_alignment)) {
+      struct memcntl_mha cmd = {0};
+      cmd.mha_pagesize = large_os_page_size;
+      cmd.mha_cmd = MHA_MAPSIZE_VA;
+      if (memcntl(p, size, MC_HAT_ADVISE, (caddr_t)&cmd, 0, 0) == 0) {
+        *is_large = true;
+      }
+    }
+    #endif
+  }
+  if (p == NULL) {
+    _mi_warning_message("unable to allocate OS memory (%zu bytes, error code: %i, address: %p, large only: %d, allow large: %d)\n", size, errno, addr, large_only, allow_large);
+  }
+  return p;
+}
+#endif
+
+// On 64-bit systems, we can do efficient aligned allocation by using
+// the 4TiB to 30TiB area to allocate them.
+#if (MI_INTPTR_SIZE >= 8) && (defined(_WIN32) || (defined(MI_OS_USE_MMAP) && !defined(MAP_ALIGNED)))
+static mi_decl_cache_align _Atomic(uintptr_t) aligned_base;
+
+// Return a 4MiB aligned address that is probably available.
+// If this returns NULL, the OS will determine the address but on some OS's that may not be 
+// properly aligned which can be more costly as it needs to be adjusted afterwards.
+// For a size > 1GiB this always returns NULL in order to guarantee good ASLR randomization; 
+// (otherwise an initial large allocation of say 2TiB has a 50% chance to include (known) addresses 
+//  in the middle of the 2TiB - 6TiB address range (see issue #372))
+
+#define KK_HINT_BASE ((uintptr_t)2 << 40)  // 2TiB start
+#define KK_HINT_AREA ((uintptr_t)4 << 40)  // upto 6TiB   (since before win8 there is "only" 8TiB available to processes)
+#define KK_HINT_MAX  ((uintptr_t)30 << 40) // wrap after 30TiB (area after 32TiB is used for huge OS pages)
+
+static void* mi_os_get_aligned_hint(size_t try_alignment, size_t size) 
+{
+  if (try_alignment == 0 || try_alignment > MI_SEGMENT_SIZE) return NULL;
+  if ((size%MI_SEGMENT_SIZE) != 0) return NULL;
+  if (size > 1*GiB) return NULL;  // guarantee the chance of fixed valid address is at most 1/(KK_HINT_AREA / 1<<30) = 1/4096.
+  #if (MI_SECURE>0)
+  size += MI_SEGMENT_SIZE;        // put in `MI_SEGMENT_SIZE` virtual gaps between hinted blocks; this splits VLA's but increases guarded areas.
+  #endif
+
+  uintptr_t hint = mi_atomic_add_acq_rel(&aligned_base, size);
+  if (hint == 0 || hint > KK_HINT_MAX) {   // wrap or initialize
+    uintptr_t init = KK_HINT_BASE;
+    #if (MI_SECURE>0 || MI_DEBUG==0)       // security: randomize start of aligned allocations unless in debug mode
+    uintptr_t r = _mi_heap_random_next(mi_get_default_heap());
+    init = init + ((MI_SEGMENT_SIZE * ((r>>17) & 0xFFFFF)) % KK_HINT_AREA);  // (randomly 20 bits)*4MiB == 0 to 4TiB
+    #endif
+    uintptr_t expected = hint + size;
+    mi_atomic_cas_strong_acq_rel(&aligned_base, &expected, init);
+    hint = mi_atomic_add_acq_rel(&aligned_base, size); // this may still give 0 or > KK_HINT_MAX but that is ok, it is a hint after all
+  }
+  if (hint%try_alignment != 0) return NULL;
+  return (void*)hint;
+}
+#else
+static void* mi_os_get_aligned_hint(size_t try_alignment, size_t size) {
+  UNUSED(try_alignment); UNUSED(size);
+  return NULL;
+}
+#endif
+
+
+// Primitive allocation from the OS.
+// Note: the `try_alignment` is just a hint and the returned pointer is not guaranteed to be aligned.
+static void* mi_os_mem_alloc(size_t size, size_t try_alignment, bool commit, bool allow_large, bool* is_large, mi_stats_t* stats) {
+  mi_assert_internal(size > 0 && (size % _mi_os_page_size()) == 0);
+  if (size == 0) return NULL;
+  if (!commit) allow_large = false;
+
+  void* p = NULL;
+  /*
+  if (commit && allow_large) {
+    p = _mi_os_try_alloc_from_huge_reserved(size, try_alignment);
+    if (p != NULL) {
+      *is_large = true;
+      return p;
+    }
+  }
+  */
+
+  #if defined(_WIN32)
+    int flags = MEM_RESERVE;
+    if (commit) flags |= MEM_COMMIT;
+    p = mi_win_virtual_alloc(NULL, size, try_alignment, flags, false, allow_large, is_large);
+  #elif defined(__wasi__)
+    *is_large = false;
+    p = mi_wasm_heap_grow(size, try_alignment);
+  #else
+    int protect_flags = (commit ? (PROT_WRITE | PROT_READ) : PROT_NONE);
+    p = mi_unix_mmap(NULL, size, try_alignment, protect_flags, false, allow_large, is_large);
+  #endif
+  mi_stat_counter_increase(stats->mmap_calls, 1);
+  if (p != NULL) {
+    _mi_stat_increase(&stats->reserved, size);
+    if (commit) { _mi_stat_increase(&stats->committed, size); }
+  }
+  return p;
+}
+
+
+// Primitive aligned allocation from the OS.
+// This function guarantees the allocated memory is aligned.
+static void* mi_os_mem_alloc_aligned(size_t size, size_t alignment, bool commit, bool allow_large, bool* is_large, mi_stats_t* stats) {
+  mi_assert_internal(alignment >= _mi_os_page_size() && ((alignment & (alignment - 1)) == 0));
+  mi_assert_internal(size > 0 && (size % _mi_os_page_size()) == 0);
+  if (!commit) allow_large = false;
+  if (!(alignment >= _mi_os_page_size() && ((alignment & (alignment - 1)) == 0))) return NULL;
+  size = _mi_align_up(size, _mi_os_page_size());
+
+  // try first with a hint (this will be aligned directly on Win 10+ or BSD)
+  void* p = mi_os_mem_alloc(size, alignment, commit, allow_large, is_large, stats);
+  if (p == NULL) return NULL;
+
+  // if not aligned, free it, overallocate, and unmap around it
+  if (((uintptr_t)p % alignment != 0)) {
+    mi_os_mem_free(p, size, commit, stats);
+    if (size >= (SIZE_MAX - alignment)) return NULL; // overflow
+    size_t over_size = size + alignment;
+
+#if _WIN32
+    // over-allocate and than re-allocate exactly at an aligned address in there.
+    // this may fail due to threads allocating at the same time so we
+    // retry this at most 3 times before giving up.
+    // (we can not decommit around the overallocation on Windows, because we can only
+    //  free the original pointer, not one pointing inside the area)
+    int flags = MEM_RESERVE;
+    if (commit) flags |= MEM_COMMIT;
+    for (int tries = 0; tries < 3; tries++) {
+      // over-allocate to determine a virtual memory range
+      p = mi_os_mem_alloc(over_size, alignment, commit, false, is_large, stats);
+      if (p == NULL) return NULL; // error
+      if (((uintptr_t)p % alignment) == 0) {
+        // if p happens to be aligned, just decommit the left-over area
+        _mi_os_decommit((uint8_t*)p + size, over_size - size, stats);
+        break;
+      }
+      else {
+        // otherwise free and allocate at an aligned address in there
+        mi_os_mem_free(p, over_size, commit, stats);
+        void* aligned_p = mi_align_up_ptr(p, alignment);
+        p = mi_win_virtual_alloc(aligned_p, size, alignment, flags, false, allow_large, is_large);
+        if (p == aligned_p) break; // success!
+        if (p != NULL) { // should not happen?
+          mi_os_mem_free(p, size, commit, stats);
+          p = NULL;
+        }
+      }
+    }
+#else
+    // overallocate...
+    p = mi_os_mem_alloc(over_size, alignment, commit, false, is_large, stats);
+    if (p == NULL) return NULL;
+    // and selectively unmap parts around the over-allocated area.
+    void* aligned_p = mi_align_up_ptr(p, alignment);
+    size_t pre_size = (uint8_t*)aligned_p - (uint8_t*)p;
+    size_t mid_size = _mi_align_up(size, _mi_os_page_size());
+    size_t post_size = over_size - pre_size - mid_size;
+    mi_assert_internal(pre_size < over_size && post_size < over_size && mid_size >= size);
+    if (pre_size > 0)  mi_os_mem_free(p, pre_size, commit, stats);
+    if (post_size > 0) mi_os_mem_free((uint8_t*)aligned_p + mid_size, post_size, commit, stats);
+    // we can return the aligned pointer on `mmap` systems
+    p = aligned_p;
+#endif
+  }
+
+  mi_assert_internal(p == NULL || (p != NULL && ((uintptr_t)p % alignment) == 0));
+  return p;
+}
+
+/* -----------------------------------------------------------
+  OS API: alloc, free, alloc_aligned
+----------------------------------------------------------- */
+
+void* _mi_os_alloc(size_t size, mi_stats_t* tld_stats) {
+  UNUSED(tld_stats);
+  mi_stats_t* stats = &_mi_stats_main;
+  if (size == 0) return NULL;
+  size = _mi_os_good_alloc_size(size);
+  bool is_large = false;
+  return mi_os_mem_alloc(size, 0, true, false, &is_large, stats);
+}
+
+void  _mi_os_free_ex(void* p, size_t size, bool was_committed, mi_stats_t* tld_stats) {
+  UNUSED(tld_stats);
+  mi_stats_t* stats = &_mi_stats_main;
+  if (size == 0 || p == NULL) return;
+  size = _mi_os_good_alloc_size(size);
+  mi_os_mem_free(p, size, was_committed, stats);
+}
+
+void  _mi_os_free(void* p, size_t size, mi_stats_t* stats) {
+  _mi_os_free_ex(p, size, true, stats);
+}
+
+void* _mi_os_alloc_aligned(size_t size, size_t alignment, bool commit, bool* large, mi_stats_t* tld_stats)
+{
+  UNUSED(tld_stats);
+  if (size == 0) return NULL;
+  size = _mi_os_good_alloc_size(size);
+  alignment = _mi_align_up(alignment, _mi_os_page_size());
+  bool allow_large = false;
+  if (large != NULL) {
+    allow_large = *large;
+    *large = false;
+  }
+  return mi_os_mem_alloc_aligned(size, alignment, commit, allow_large, (large!=NULL?large:&allow_large), &_mi_stats_main /*tld->stats*/ );
+}
+
+
+
+/* -----------------------------------------------------------
+  OS memory API: reset, commit, decommit, protect, unprotect.
+----------------------------------------------------------- */
+
+
+// OS page align within a given area, either conservative (pages inside the area only),
+// or not (straddling pages outside the area is possible)
+static void* mi_os_page_align_areax(bool conservative, void* addr, size_t size, size_t* newsize) {
+  mi_assert(addr != NULL && size > 0);
+  if (newsize != NULL) *newsize = 0;
+  if (size == 0 || addr == NULL) return NULL;
+
+  // page align conservatively within the range
+  void* start = (conservative ? mi_align_up_ptr(addr, _mi_os_page_size())
+    : mi_align_down_ptr(addr, _mi_os_page_size()));
+  void* end = (conservative ? mi_align_down_ptr((uint8_t*)addr + size, _mi_os_page_size())
+    : mi_align_up_ptr((uint8_t*)addr + size, _mi_os_page_size()));
+  ptrdiff_t diff = (uint8_t*)end - (uint8_t*)start;
+  if (diff <= 0) return NULL;
+
+  mi_assert_internal((conservative && (size_t)diff <= size) || (!conservative && (size_t)diff >= size));
+  if (newsize != NULL) *newsize = (size_t)diff;
+  return start;
+}
+
+static void* mi_os_page_align_area_conservative(void* addr, size_t size, size_t* newsize) {
+  return mi_os_page_align_areax(true, addr, size, newsize);
+}
+
+static void mi_mprotect_hint(int err) {
+#if defined(MI_OS_USE_MMAP) && (MI_SECURE>=2) // guard page around every mimalloc page
+  if (err == ENOMEM) {
+    _mi_warning_message("the previous warning may have been caused by a low memory map limit.\n"
+                        "  On Linux this is controlled by the vm.max_map_count. For example:\n"
+                        "  > sudo sysctl -w vm.max_map_count=262144\n");
+  }
+#else
+  UNUSED(err);
+#endif
+}
+
+// Commit/Decommit memory.
+// Usually commit is aligned liberal, while decommit is aligned conservative.
+// (but not for the reset version where we want commit to be conservative as well)
+static bool mi_os_commitx(void* addr, size_t size, bool commit, bool conservative, bool* is_zero, mi_stats_t* stats) {
+  // page align in the range, commit liberally, decommit conservative
+  if (is_zero != NULL) { *is_zero = false; }
+  size_t csize;
+  void* start = mi_os_page_align_areax(conservative, addr, size, &csize);
+  if (csize == 0) return true;  // || _mi_os_is_huge_reserved(addr))
+  int err = 0;
+  if (commit) {
+    _mi_stat_increase(&stats->committed, size);  // use size for precise commit vs. decommit
+    _mi_stat_counter_increase(&stats->commit_calls, 1);
+  }
+  else {
+    _mi_stat_decrease(&stats->committed, size);
+  }
+
+  #if defined(_WIN32)
+  if (commit) {
+    // if the memory was already committed, the call succeeds but it is not zero'd
+    // *is_zero = true;
+    void* p = VirtualAlloc(start, csize, MEM_COMMIT, PAGE_READWRITE);
+    err = (p == start ? 0 : GetLastError());
+  }
+  else {
+    BOOL ok = VirtualFree(start, csize, MEM_DECOMMIT);
+    err = (ok ? 0 : GetLastError());
+  }
+  #elif defined(__wasi__)
+  // WebAssembly guests can't control memory protection
+  #elif defined(MAP_FIXED)
+  if (!commit) {
+    // use mmap with MAP_FIXED to discard the existing memory (and reduce commit charge)
+    void* p = mmap(start, csize, PROT_NONE, (MAP_FIXED | MAP_PRIVATE | MAP_ANONYMOUS | MAP_NORESERVE), -1, 0);
+    if (p != start) { err = errno; }
+  }
+  else {
+    // for commit, just change the protection
+    err = mprotect(start, csize, (PROT_READ | PROT_WRITE));
+    if (err != 0) { err = errno; }
+    #if defined(MADV_FREE_REUSE)
+      while ((err = madvise(start, csize, MADV_FREE_REUSE)) != 0 && errno == EAGAIN) { errno = 0; }
+    #endif
+  }
+  #else
+  err = mprotect(start, csize, (commit ? (PROT_READ | PROT_WRITE) : PROT_NONE));
+  if (err != 0) { err = errno; }
+  #endif
+  if (err != 0) {
+    _mi_warning_message("%s error: start: %p, csize: 0x%x, err: %i\n", commit ? "commit" : "decommit", start, csize, err);
+    mi_mprotect_hint(err);
+  }
+  mi_assert_internal(err == 0);
+  return (err == 0);
+}
+
+bool _mi_os_commit(void* addr, size_t size, bool* is_zero, mi_stats_t* tld_stats) {
+  UNUSED(tld_stats);
+  mi_stats_t* stats = &_mi_stats_main;
+  return mi_os_commitx(addr, size, true, false /* liberal */, is_zero, stats);
+}
+
+bool _mi_os_decommit(void* addr, size_t size, mi_stats_t* tld_stats) {
+  UNUSED(tld_stats);
+  mi_stats_t* stats = &_mi_stats_main;
+  bool is_zero;
+  return mi_os_commitx(addr, size, false, true /* conservative */, &is_zero, stats);
+}
+
+static bool mi_os_commit_unreset(void* addr, size_t size, bool* is_zero, mi_stats_t* stats) {  
+  return mi_os_commitx(addr, size, true, true /* conservative */, is_zero, stats);
+}
+
+// Signal to the OS that the address range is no longer in use
+// but may be used later again. This will release physical memory
+// pages and reduce swapping while keeping the memory committed.
+// We page align to a conservative area inside the range to reset.
+static bool mi_os_resetx(void* addr, size_t size, bool reset, mi_stats_t* stats) {
+  // page align conservatively within the range
+  size_t csize;
+  void* start = mi_os_page_align_area_conservative(addr, size, &csize);
+  if (csize == 0) return true;  // || _mi_os_is_huge_reserved(addr)
+  if (reset) _mi_stat_increase(&stats->reset, csize);
+        else _mi_stat_decrease(&stats->reset, csize);
+  if (!reset) return true; // nothing to do on unreset!
+
+  #if (MI_DEBUG>1)
+  if (MI_SECURE==0) {
+    memset(start, 0, csize); // pretend it is eagerly reset
+  }
+  #endif
+
+#if defined(_WIN32)
+  // Testing shows that for us (on `malloc-large`) MEM_RESET is 2x faster than DiscardVirtualMemory
+  void* p = VirtualAlloc(start, csize, MEM_RESET, PAGE_READWRITE);
+  mi_assert_internal(p == start);
+  #if 1
+  if (p == start && start != NULL) {
+    VirtualUnlock(start,csize); // VirtualUnlock after MEM_RESET removes the memory from the working set
+  }
+  #endif
+  if (p != start) return false;
+#else
+#if defined(MADV_FREE)
+  #if defined(MADV_FREE_REUSABLE)
+    #define KK_MADV_FREE_INITIAL  MADV_FREE_REUSABLE
+  #else
+    #define KK_MADV_FREE_INITIAL  MADV_FREE
+  #endif
+  static _Atomic(uintptr_t) advice = ATOMIC_VAR_INIT(KK_MADV_FREE_INITIAL);
+  int oadvice = (int)mi_atomic_load_relaxed(&advice);
+  int err;
+  while ((err = madvise(start, csize, oadvice)) != 0 && errno == EAGAIN) { errno = 0;  };
+  if (err != 0 && errno == EINVAL && oadvice == KK_MADV_FREE_INITIAL) {  
+    // if MADV_FREE/MADV_FREE_REUSABLE is not supported, fall back to MADV_DONTNEED from now on
+    mi_atomic_store_release(&advice, (uintptr_t)MADV_DONTNEED);
+    err = madvise(start, csize, MADV_DONTNEED);
+  }
+#elif defined(__wasi__)
+  int err = 0;
+#else
+  int err = madvise(start, csize, MADV_DONTNEED);
+#endif
+  if (err != 0) {
+    _mi_warning_message("madvise reset error: start: %p, csize: 0x%x, errno: %i\n", start, csize, errno);
+  }
+  //mi_assert(err == 0);
+  if (err != 0) return false;
+#endif
+  return true;
+}
+
+// Signal to the OS that the address range is no longer in use
+// but may be used later again. This will release physical memory
+// pages and reduce swapping while keeping the memory committed.
+// We page align to a conservative area inside the range to reset.
+bool _mi_os_reset(void* addr, size_t size, mi_stats_t* tld_stats) {
+  UNUSED(tld_stats);
+  mi_stats_t* stats = &_mi_stats_main;
+  if (mi_option_is_enabled(mi_option_reset_decommits)) {
+    return _mi_os_decommit(addr, size, stats);
+  }
+  else {
+    return mi_os_resetx(addr, size, true, stats);
+  }
+}
+
+bool _mi_os_unreset(void* addr, size_t size, bool* is_zero, mi_stats_t* tld_stats) {
+  UNUSED(tld_stats);
+  mi_stats_t* stats = &_mi_stats_main;
+  if (mi_option_is_enabled(mi_option_reset_decommits)) {
+    return mi_os_commit_unreset(addr, size, is_zero, stats);  // re-commit it (conservatively!)
+  }
+  else {
+    *is_zero = false;
+    return mi_os_resetx(addr, size, false, stats);
+  }
+}
+
+
+// Protect a region in memory to be not accessible.
+static  bool mi_os_protectx(void* addr, size_t size, bool protect) {
+  // page align conservatively within the range
+  size_t csize = 0;
+  void* start = mi_os_page_align_area_conservative(addr, size, &csize);
+  if (csize == 0) return false;
+  /*
+  if (_mi_os_is_huge_reserved(addr)) {
+	  _mi_warning_message("cannot mprotect memory allocated in huge OS pages\n");
+  }
+  */
+  int err = 0;
+#ifdef _WIN32
+  DWORD oldprotect = 0;
+  BOOL ok = VirtualProtect(start, csize, protect ? PAGE_NOACCESS : PAGE_READWRITE, &oldprotect);
+  err = (ok ? 0 : GetLastError());
+#elif defined(__wasi__)
+  err = 0;
+#else
+  err = mprotect(start, csize, protect ? PROT_NONE : (PROT_READ | PROT_WRITE));
+  if (err != 0) { err = errno; }
+#endif
+  if (err != 0) {
+    _mi_warning_message("mprotect error: start: %p, csize: 0x%x, err: %i\n", start, csize, err);
+    mi_mprotect_hint(err);
+  }
+  return (err == 0);
+}
+
+bool _mi_os_protect(void* addr, size_t size) {
+  return mi_os_protectx(addr, size, true);
+}
+
+bool _mi_os_unprotect(void* addr, size_t size) {
+  return mi_os_protectx(addr, size, false);
+}
+
+
+
+bool _mi_os_shrink(void* p, size_t oldsize, size_t newsize, mi_stats_t* stats) {
+  // page align conservatively within the range
+  mi_assert_internal(oldsize > newsize && p != NULL);
+  if (oldsize < newsize || p == NULL) return false;
+  if (oldsize == newsize) return true;
+
+  // oldsize and newsize should be page aligned or we cannot shrink precisely
+  void* addr = (uint8_t*)p + newsize;
+  size_t size = 0;
+  void* start = mi_os_page_align_area_conservative(addr, oldsize - newsize, &size);
+  if (size == 0 || start != addr) return false;
+
+#ifdef _WIN32
+  // we cannot shrink on windows, but we can decommit
+  return _mi_os_decommit(start, size, stats);
+#else
+  return mi_os_mem_free(start, size, true, stats);
+#endif
+}
+
+
+/* ----------------------------------------------------------------------------
+Support for allocating huge OS pages (1Gib) that are reserved up-front
+and possibly associated with a specific NUMA node. (use `numa_node>=0`)
+-----------------------------------------------------------------------------*/
+#define MI_HUGE_OS_PAGE_SIZE  (GiB)
+
+#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%GiB == 0);
+  mi_assert_internal(addr != NULL);
+  const DWORD flags = MEM_LARGE_PAGES | MEM_COMMIT | MEM_RESERVE;
+
+  mi_win_enable_large_os_pages();
+
+  #if defined(MEM_EXTENDED_PARAMETER_TYPE_BITS)
+  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) {
+    #ifndef MEM_EXTENDED_PARAMETER_NONPAGED_HUGE
+    #define MEM_EXTENDED_PARAMETER_NONPAGED_HUGE  (0x10)
+    #endif
+    params[0].Type = 5; // == MemExtendedParameterAttributeFlags;
+    params[0].ULong64 = MEM_EXTENDED_PARAMETER_NONPAGED_HUGE;
+    ULONG param_count = 1;
+    if (numa_node >= 0) {
+      param_count++;
+      params[1].Type = MemExtendedParameterNumaNode;
+      params[1].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 (1gb) pages, trying large (2mb) 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 = MemExtendedParameterNumaNode;
+    params[0].ULong = (unsigned)numa_node;
+    return (*pVirtualAlloc2)(GetCurrentProcess(), addr, size, flags, PAGE_READWRITE, params, 1);
+  }
+  #else
+    UNUSED(numa_node);
+  #endif
+  // 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>
+#ifndef MPOL_PREFERRED
+#define MPOL_PREFERRED 1
+#endif
+#if defined(SYS_mbind)
+static long mi_os_mbind(void* start, unsigned long len, unsigned long mode, const unsigned long* nmask, unsigned long maxnode, unsigned flags) {
+  return syscall(SYS_mbind, start, len, mode, nmask, maxnode, flags);
+}
+#else
+static long mi_os_mbind(void* start, unsigned long len, unsigned long mode, const unsigned long* nmask, unsigned long maxnode, unsigned flags) {
+  UNUSED(start); UNUSED(len); UNUSED(mode); UNUSED(nmask); UNUSED(maxnode); UNUSED(flags);
+  return 0;
+}
+#endif
+static void* mi_os_alloc_huge_os_pagesx(void* addr, size_t size, int numa_node) {
+  mi_assert_internal(size%GiB == 0);
+  bool is_large = true;
+  void* p = mi_unix_mmap(addr, size, MI_SEGMENT_SIZE, PROT_READ | PROT_WRITE, true, true, &is_large);
+  if (p == NULL) return NULL;
+  if (numa_node >= 0 && numa_node < 8*MI_INTPTR_SIZE) { // at most 64 nodes
+    uintptr_t numa_mask = (1UL << numa_node);
+    // TODO: does `mbind` work correctly for huge OS pages? should we
+    // use `set_mempolicy` before calling mmap instead?
+    // see: <https://lkml.org/lkml/2017/2/9/875>
+    long err = mi_os_mbind(p, size, MPOL_PREFERRED, &numa_mask, 8*MI_INTPTR_SIZE, 0);
+    if (err != 0) {
+      _mi_warning_message("failed to bind huge (1gb) pages to numa node %d: %s\n", numa_node, strerror(errno));
+    }
+  }
+  return p;
+}
+#else
+static void* mi_os_alloc_huge_os_pagesx(void* addr, size_t size, int numa_node) {
+  UNUSED(addr); UNUSED(size); UNUSED(numa_node);
+  return NULL;
+}
+#endif
+
+#if (MI_INTPTR_SIZE >= 8)
+// To ensure proper alignment, use our own area for huge OS pages
+static mi_decl_cache_align _Atomic(uintptr_t)  mi_huge_start; // = 0
+
+// Claim an aligned address range for huge pages
+static uint8_t* mi_os_claim_huge_pages(size_t pages, size_t* total_size) {
+  if (total_size != NULL) *total_size = 0;
+  const size_t size = pages * MI_HUGE_OS_PAGE_SIZE;
+
+  uintptr_t start = 0;
+  uintptr_t end = 0;
+  uintptr_t huge_start = mi_atomic_load_relaxed(&mi_huge_start);
+  do {
+    start = huge_start;
+    if (start == 0) {
+      // Initialize the start address after the 32TiB area
+      start = ((uintptr_t)32 << 40);  // 32TiB virtual start address
+#if (MI_SECURE>0 || MI_DEBUG==0)      // security: randomize start of huge pages unless in debug mode
+      uintptr_t r = _mi_heap_random_next(mi_get_default_heap());
+      start = start + ((uintptr_t)MI_HUGE_OS_PAGE_SIZE * ((r>>17) & 0x0FFF));  // (randomly 12bits)*1GiB == between 0 to 4TiB
+#endif
+    }
+    end = start + size;
+    mi_assert_internal(end % MI_SEGMENT_SIZE == 0);
+  } while (!mi_atomic_cas_strong_acq_rel(&mi_huge_start, &huge_start, end));
+
+  if (total_size != NULL) *total_size = size;
+  return (uint8_t*)start;
+}
+#else
+static uint8_t* mi_os_claim_huge_pages(size_t pages, size_t* total_size) {
+  UNUSED(pages);
+  if (total_size != NULL) *total_size = 0;
+  return NULL;
+}
+#endif
+
+// Allocate MI_SEGMENT_SIZE aligned huge pages
+void* _mi_os_alloc_huge_os_pages(size_t pages, int numa_node, mi_msecs_t max_msecs, size_t* pages_reserved, size_t* psize) {
+  if (psize != NULL) *psize = 0;
+  if (pages_reserved != NULL) *pages_reserved = 0;
+  size_t size = 0;
+  uint8_t* start = mi_os_claim_huge_pages(pages, &size);
+  if (start == NULL) return NULL; // or 32-bit systems
+
+  // Allocate one page at the time but try to place them contiguously
+  // We allocate one page at the time to be able to abort if it takes too long
+  // or to at least allocate as many as available on the system.
+  mi_msecs_t start_t = _mi_clock_start();
+  size_t page;
+  for (page = 0; page < pages; page++) {
+    // allocate a page
+    void* addr = start + (page * MI_HUGE_OS_PAGE_SIZE);
+    void* p = mi_os_alloc_huge_os_pagesx(addr, MI_HUGE_OS_PAGE_SIZE, numa_node);
+
+    // Did we succeed at a contiguous address?
+    if (p != addr) {
+      // no success, issue a warning and break
+      if (p != NULL) {
+        _mi_warning_message("could not allocate contiguous huge page %zu at %p\n", page, addr);
+        _mi_os_free(p, MI_HUGE_OS_PAGE_SIZE, &_mi_stats_main);
+      }
+      break;
+    }
+
+    // success, record it
+    _mi_stat_increase(&_mi_stats_main.committed, MI_HUGE_OS_PAGE_SIZE);
+    _mi_stat_increase(&_mi_stats_main.reserved, MI_HUGE_OS_PAGE_SIZE);
+
+    // check for timeout
+    if (max_msecs > 0) {
+      mi_msecs_t elapsed = _mi_clock_end(start_t);
+      if (page >= 1) {
+        mi_msecs_t estimate = ((elapsed / (page+1)) * pages);
+        if (estimate > 2*max_msecs) { // seems like we are going to timeout, break
+          elapsed = max_msecs + 1;
+        }
+      }
+      if (elapsed > max_msecs) {
+        _mi_warning_message("huge page allocation timed out\n");
+        break;
+      }
+    }
+  }
+  mi_assert_internal(page*MI_HUGE_OS_PAGE_SIZE <= size);
+  if (pages_reserved != NULL) *pages_reserved = page;
+  if (psize != NULL) *psize = page * MI_HUGE_OS_PAGE_SIZE;
+  return (page == 0 ? NULL : start);
+}
+
+// free every huge page in a range individually (as we allocated per page)
+// note: needed with VirtualAlloc but could potentially be done in one go on mmap'd systems.
+void _mi_os_free_huge_pages(void* p, size_t size, mi_stats_t* stats) {
+  if (p==NULL || size==0) return;
+  uint8_t* base = (uint8_t*)p;
+  while (size >= MI_HUGE_OS_PAGE_SIZE) {
+    _mi_os_free(base, MI_HUGE_OS_PAGE_SIZE, stats);
+    size -= MI_HUGE_OS_PAGE_SIZE;
+  }
+}
+
+/* ----------------------------------------------------------------------------
+Support NUMA aware allocation
+-----------------------------------------------------------------------------*/
+#ifdef _WIN32  
+static size_t mi_os_numa_nodex() {
+  USHORT numa_node = 0;
+  if (pGetCurrentProcessorNumberEx != NULL && pGetNumaProcessorNodeEx != NULL) {
+    // Extended API is supported
+    PROCESSOR_NUMBER pnum;
+    (*pGetCurrentProcessorNumberEx)(&pnum);
+    USHORT nnode = 0;
+    BOOL ok = (*pGetNumaProcessorNodeEx)(&pnum, &nnode);
+    if (ok) numa_node = nnode;
+  }
+  else {
+    // Vista or earlier, use older API that is limited to 64 processors. Issue #277
+    DWORD pnum = GetCurrentProcessorNumber();
+    UCHAR nnode = 0;
+    BOOL ok = GetNumaProcessorNode((UCHAR)pnum, &nnode);
+    if (ok) numa_node = nnode;    
+  }
+  return numa_node;
+}
+
+static size_t mi_os_numa_node_countx(void) {
+  ULONG numa_max = 0;
+  GetNumaHighestNodeNumber(&numa_max);
+  // find the highest node number that has actual processors assigned to it. Issue #282
+  while(numa_max > 0) {
+    if (pGetNumaNodeProcessorMaskEx != NULL) {
+      // Extended API is supported
+      GROUP_AFFINITY affinity;
+      if ((*pGetNumaNodeProcessorMaskEx)((USHORT)numa_max, &affinity)) {
+        if (affinity.Mask != 0) break;  // found the maximum non-empty node
+      }
+    }
+    else {
+      // Vista or earlier, use older API that is limited to 64 processors.
+      ULONGLONG mask;
+      if (GetNumaNodeProcessorMask((UCHAR)numa_max, &mask)) {
+        if (mask != 0) break; // found the maximum non-empty node
+      };
+    }
+    // max node was invalid or had no processor assigned, try again
+    numa_max--;
+  }
+  return ((size_t)numa_max + 1);
+}
+#elif defined(__linux__)
+#include <sys/syscall.h>  // getcpu
+#include <stdio.h>        // access
+
+static size_t mi_os_numa_nodex(void) {
+#ifdef SYS_getcpu
+  unsigned long node = 0;
+  unsigned long ncpu = 0;
+  long err = syscall(SYS_getcpu, &ncpu, &node, NULL);
+  if (err != 0) return 0;
+  return node;
+#else
+  return 0;
+#endif
+}
+static size_t mi_os_numa_node_countx(void) {
+  char buf[128];
+  unsigned node = 0;
+  for(node = 0; node < 256; node++) {
+    // enumerate node entries -- todo: it there a more efficient way to do this? (but ensure there is no allocation)
+    snprintf(buf, 127, "/sys/devices/system/node/node%u", node + 1);
+    if (access(buf,R_OK) != 0) break;
+  }
+  return (node+1);
+}
+#else
+static size_t mi_os_numa_nodex(void) {
+  return 0;
+}
+static size_t mi_os_numa_node_countx(void) {
+  return 1;
+}
+#endif
+
+_Atomic(size_t)  _mi_numa_node_count; // = 0   // cache the node count
+
+size_t _mi_os_numa_node_count_get(void) {
+  size_t count = mi_atomic_load_acquire(&_mi_numa_node_count);
+  if (count <= 0) {
+    long ncount = mi_option_get(mi_option_use_numa_nodes); // given explicitly?
+    if (ncount > 0) {
+      count = (size_t)ncount;
+    }
+    else {
+      count = mi_os_numa_node_countx(); // or detect dynamically
+      if (count == 0) count = 1;
+    }    
+    mi_atomic_store_release(&_mi_numa_node_count, count); // save it
+    _mi_verbose_message("using %zd numa regions\n", count);
+  }
+  return count;
+}
+
+int _mi_os_numa_node_get(mi_os_tld_t* tld) {
+  UNUSED(tld);
+  size_t numa_count = _mi_os_numa_node_count();
+  if (numa_count<=1) return 0; // optimize on single numa node systems: always node 0
+  // never more than the node count and >= 0
+  size_t numa_node = mi_os_numa_nodex();
+  if (numa_node >= numa_count) { numa_node = numa_node % numa_count; }
+  return (int)numa_node;
+}