gh-144319: obtain SeLockMemoryPrivilege on Windows#144928
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pablogsal merged 3 commits intopython:mainfrom Mar 23, 2026
Merged
gh-144319: obtain SeLockMemoryPrivilege on Windows#144928pablogsal merged 3 commits intopython:mainfrom
pablogsal merged 3 commits intopython:mainfrom
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can be used on Windows
chris-eibl
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ZeroIntensity,
corona10,
emmatyping,
ericsnowcurrently and
erlend-aasland
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Skipping news because that's already covered by @pablogsal 's previous PRs. |
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pablogsal
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LGTM! Thanks for working in this 🤘
| // but without having all privileges adjusted (ERROR_NOT_ALL_ASSIGNED). | ||
| BOOL status = AdjustTokenPrivileges(hToken, FALSE, &tp, sizeof(TOKEN_PRIVILEGES), NULL, NULL); | ||
| DWORD error = GetLastError(); | ||
| if (!status || (error != ERROR_SUCCESS)) |
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If I am not missing anything seems that the MSDN docs state that AdjustTokenPrivileges returns nonzero (success) even when not all privileges were adjusted: we correctly handle this via GetLastError(). However, the error message "failed to obtain SeLockMemoryPrivilege for huge pages" doesn’t distinguish between:
- The token adjustment API failing entirely
- The privilege simply not being held
The second case is the common, expected failure mode (user just doesn’t have the privilege). A more actionable error message for that case would help like perhaps "SeLockMemoryPrivilege not held; grant it via Local Security Policy or disable PYTHON_PYMALLOC_HUGEPAGES".
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CuriousLearner
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Mar 24, 2026
…on into fix-pythongh-138577 * 'fix-pythongh-138577' of github.com:CuriousLearner/cpython: pythongh-146202: Create tmp_dir in regrtest worker (python#146347) pythongh-144319: obtain SeLockMemoryPrivilege on Windows (python#144928) pythongh-146199: Fix error handling in `code_richcompare` when `PyObject_RichCompareBool` fails (python#146200) pythongh-146197: Include a bit more information in sys._emscripten_info.runtime (python#146346) pythongh-135871: Reload lock internal state while spinning in `PyMutex_LockTimed` (pythongh-146064) pythongh-145719: Add `.efi` file detection in `mimetypes` (python#145720)
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Obtain SeLockMemoryPrivilege on startup on Windows to be able to use large pages when requested by setting the environment variable
PYTHON_PYMALLOC_HUGEPAGES.I've decided to fail if that doesn't succeed instead of silently switching to normal 4K pages and updated the documentation.
Using
bench_obmalloc.pyfrom the issue I getfor an AMD64 VS2026 release build (no PGO) on my PC (Haswell i5-4570, Windows 10).
📚 Documentation preview 📚: https://cpython-previews--144928.org.readthedocs.build/