windows flags

Author: Pablo Galindo Salgado

Doc/using/configure.rst

@@ -793,6 +793,9 @@ also be used to improve performance.
    The configure script checks that the platform supports ``MAP_HUGETLB``
    and emits a warning if it is not available.
 
+   On Windows, use the ``--pymalloc-hugepages`` flag with ``build.bat`` or
+   set the ``UsePymallocHugepages`` MSBuild property.
+
    .. versionadded:: 3.15
 
 .. option:: --without-doc-strings

Doc/whatsnew/3.15.rst

@@ -1481,6 +1481,7 @@ Build changes
   page support for :ref:`pymalloc <pymalloc>` arenas. When enabled, arena size
   increases to 2 MiB and allocation uses ``MAP_HUGETLB`` (Linux) or
   ``MEM_LARGE_PAGES`` (Windows) with automatic fallback to regular pages.
+  On Windows, use ``build.bat --pymalloc-hugepages``.
 
 * Annotating anonymous mmap usage is now supported if Linux kernel supports
   :manpage:`PR_SET_VMA_ANON_NAME <PR_SET_VMA(2const)>` (Linux 5.17 or newer).

Lib/lib2to3/Grammar3.12.10.final.0.pickle

@@ -0,0 +1,2 @@
+Fix race conditions during runtime finalization that could lead to accessing
+freed memory.

Lib/lib2to3/PatternGrammar3.12.10.final.0.pickle

@@ -42,6 +42,7 @@ echo.  --experimental-jit-interpreter  Enable the experimental Tier 2 interprete
 echo.  --pystats      Enable PyStats collection.
 echo.  --tail-call-interp  Enable tail-calling interpreter (requires LLVM 19 or higher).
 echo.  --enable-stackref-debug  Enable stackref debugging mode.
+echo.  --pymalloc-hugepages  Enable huge page support for pymalloc arenas.
 echo.
 echo.Available flags to avoid building certain modules.
 echo.These flags have no effect if '-e' is not given:
@@ -100,6 +101,7 @@ if "%~1"=="--without-remote-debug" (set DisableRemoteDebug=true) & shift & goto
 if "%~1"=="--pystats" (set PyStats=1) & shift & goto CheckOpts
 if "%~1"=="--tail-call-interp" (set UseTailCallInterp=true) & shift & goto CheckOpts
 if "%~1"=="--enable-stackref-debug" (set StackRefDebug=true) & shift & goto CheckOpts
+if "%~1"=="--pymalloc-hugepages" (set UsePymallocHugepages=true) & shift & goto CheckOpts
 rem These use the actual property names used by MSBuild.  We could just let
 rem them in through the environment, but we specify them on the command line
 rem anyway for visibility so set defaults after this
@@ -205,6 +207,7 @@ echo on
  /p:UseTailCallInterp=%UseTailCallInterp%^
  /p:DisableRemoteDebug=%DisableRemoteDebug%^
  /p:StackRefDebug=%StackRefDebug%^
+ /p:UsePymallocHugepages=%UsePymallocHugepages%^
  %1 %2 %3 %4 %5 %6 %7 %8 %9
 
 @echo off

Misc/NEWS.d/next/Core_and_Builtins/2025-02-27-18-48-42.gh-issue-124878.DS0MIL.rst

@@ -50,11 +50,12 @@
     <_PlatformPreprocessorDefinition Condition="$(Platform) == 'x64' and $(PlatformToolset) != 'ClangCL'">_M_X64;$(_PlatformPreprocessorDefinition)</_PlatformPreprocessorDefinition>
     <_Py3NamePreprocessorDefinition>PY3_DLLNAME=L"$(Py3DllName)$(PyDebugExt)";</_Py3NamePreprocessorDefinition>
     <_FreeThreadedPreprocessorDefinition Condition="$(DisableGil) == 'true'">Py_GIL_DISABLED=1;</_FreeThreadedPreprocessorDefinition>
+    <_PymallocHugepagesPreprocessorDefinition Condition="$(UsePymallocHugepages) == 'true'">PYMALLOC_USE_HUGEPAGES=1;</_PymallocHugepagesPreprocessorDefinition>
   </PropertyGroup>
   <ItemDefinitionGroup>
     <ClCompile>
       <AdditionalIncludeDirectories>$(PySourcePath)Include;$(PySourcePath)Include\internal;$(PySourcePath)Include\internal\mimalloc;$(PySourcePath)PC;%(AdditionalIncludeDirectories)</AdditionalIncludeDirectories>
-      <PreprocessorDefinitions>WIN32;$(_Py3NamePreprocessorDefinition)$(_PlatformPreprocessorDefinition)$(_DebugPreprocessorDefinition)$(_PyStatsPreprocessorDefinition)$(_PydPreprocessorDefinition)$(_FreeThreadedPreprocessorDefinition)%(PreprocessorDefinitions)</PreprocessorDefinitions>
+      <PreprocessorDefinitions>WIN32;$(_Py3NamePreprocessorDefinition)$(_PlatformPreprocessorDefinition)$(_DebugPreprocessorDefinition)$(_PyStatsPreprocessorDefinition)$(_PydPreprocessorDefinition)$(_FreeThreadedPreprocessorDefinition)$(_PymallocHugepagesPreprocessorDefinition)%(PreprocessorDefinitions)</PreprocessorDefinitions>
       <PreprocessorDefinitions Condition="'$(SupportPGO)' and ($(Configuration) == 'PGInstrument' or $(Configuration) == 'PGUpdate')">_Py_USING_PGO=1;%(PreprocessorDefinitions)</PreprocessorDefinitions>
 
       <Optimization>MaxSpeed</Optimization>

PCbuild/build.bat

@@ -359,6 +359,11 @@ Supported flags are:
 * WITH_COMPUTED_GOTOS: build the interpreter using "computed gotos".
   Currently only supported by clang-cl.
 
+* UsePymallocHugepages: enable huge page support for pymalloc arenas.
+  When enabled, the arena size on 64-bit platforms is increased to 2 MiB
+  and arena allocation uses MEM_LARGE_PAGES with automatic fallback to
+  regular pages. Can also be enabled via `--pymalloc-hugepages` flag.
+
 
 Static library
 --------------