worker: ability to disable thread unsafe tasks
The worker on Windows is implemented using a thread pool. If worker
tasks are not thread safe, badness can occur. In addition, if tasks
are executing CPU bound code and holding onto the GIL, there will be
non-substantial overhead in Python context switching between active
threads. This can result in significant slowdowns of tasks.
This commit teaches the code for determining whether to use a worker
to take thread safety into account. Effectively, thread unsafe tasks
don't use the thread-based worker on Windows.
Differential Revision: https://phab.mercurial-scm.org/D3962
# Files that just need to be migrated to the formatter.
# Do not add new files here!
mercurial/cext/dirs.c
mercurial/cext/manifest.c
mercurial/cext/osutil.c
mercurial/cext/revlog.c
# Vendored code that we should never format:
contrib/python-zstandard/c-ext/bufferutil.c
contrib/python-zstandard/c-ext/compressiondict.c
contrib/python-zstandard/c-ext/compressionparams.c
contrib/python-zstandard/c-ext/compressionreader.c
contrib/python-zstandard/c-ext/compressionwriter.c
contrib/python-zstandard/c-ext/compressobj.c
contrib/python-zstandard/c-ext/compressor.c
contrib/python-zstandard/c-ext/compressoriterator.c
contrib/python-zstandard/c-ext/constants.c
contrib/python-zstandard/c-ext/decompressionreader.c
contrib/python-zstandard/c-ext/decompressionwriter.c
contrib/python-zstandard/c-ext/decompressobj.c
contrib/python-zstandard/c-ext/decompressor.c
contrib/python-zstandard/c-ext/decompressoriterator.c
contrib/python-zstandard/c-ext/frameparams.c
contrib/python-zstandard/c-ext/python-zstandard.h
contrib/python-zstandard/zstd.c
contrib/python-zstandard/zstd/common/bitstream.h
contrib/python-zstandard/zstd/common/compiler.h
contrib/python-zstandard/zstd/common/cpu.h
contrib/python-zstandard/zstd/common/entropy_common.c
contrib/python-zstandard/zstd/common/error_private.c
contrib/python-zstandard/zstd/common/error_private.h
contrib/python-zstandard/zstd/common/fse_decompress.c
contrib/python-zstandard/zstd/common/fse.h
contrib/python-zstandard/zstd/common/huf.h
contrib/python-zstandard/zstd/common/mem.h
contrib/python-zstandard/zstd/common/pool.c
contrib/python-zstandard/zstd/common/pool.h
contrib/python-zstandard/zstd/common/threading.c
contrib/python-zstandard/zstd/common/threading.h
contrib/python-zstandard/zstd/common/xxhash.c
contrib/python-zstandard/zstd/common/xxhash.h
contrib/python-zstandard/zstd/common/zstd_common.c
contrib/python-zstandard/zstd/common/zstd_errors.h
contrib/python-zstandard/zstd/common/zstd_internal.h
contrib/python-zstandard/zstd/compress/fse_compress.c
contrib/python-zstandard/zstd/compress/huf_compress.c
contrib/python-zstandard/zstd/compress/zstd_compress.c
contrib/python-zstandard/zstd/compress/zstd_compress_internal.h
contrib/python-zstandard/zstd/compress/zstd_double_fast.c
contrib/python-zstandard/zstd/compress/zstd_double_fast.h
contrib/python-zstandard/zstd/compress/zstd_fast.c
contrib/python-zstandard/zstd/compress/zstd_fast.h
contrib/python-zstandard/zstd/compress/zstd_lazy.c
contrib/python-zstandard/zstd/compress/zstd_lazy.h
contrib/python-zstandard/zstd/compress/zstd_ldm.c
contrib/python-zstandard/zstd/compress/zstd_ldm.h
contrib/python-zstandard/zstd/compress/zstdmt_compress.c
contrib/python-zstandard/zstd/compress/zstdmt_compress.h
contrib/python-zstandard/zstd/compress/zstd_opt.c
contrib/python-zstandard/zstd/compress/zstd_opt.h
contrib/python-zstandard/zstd/decompress/huf_decompress.c
contrib/python-zstandard/zstd/decompress/zstd_decompress.c
contrib/python-zstandard/zstd/deprecated/zbuff_common.c
contrib/python-zstandard/zstd/deprecated/zbuff_compress.c
contrib/python-zstandard/zstd/deprecated/zbuff_decompress.c
contrib/python-zstandard/zstd/deprecated/zbuff.h
contrib/python-zstandard/zstd/dictBuilder/cover.c
contrib/python-zstandard/zstd/dictBuilder/divsufsort.c
contrib/python-zstandard/zstd/dictBuilder/divsufsort.h
contrib/python-zstandard/zstd/dictBuilder/zdict.c
contrib/python-zstandard/zstd/dictBuilder/zdict.h
contrib/python-zstandard/zstd/zstd.h
hgext/fsmonitor/pywatchman/bser.c
mercurial/thirdparty/xdiff/xdiff.h
mercurial/thirdparty/xdiff/xdiffi.c
mercurial/thirdparty/xdiff/xdiffi.h
mercurial/thirdparty/xdiff/xemit.c
mercurial/thirdparty/xdiff/xemit.h
mercurial/thirdparty/xdiff/xhistogram.c
mercurial/thirdparty/xdiff/xinclude.h
mercurial/thirdparty/xdiff/xmacros.h
mercurial/thirdparty/xdiff/xmerge.c
mercurial/thirdparty/xdiff/xpatience.c
mercurial/thirdparty/xdiff/xprepare.c
mercurial/thirdparty/xdiff/xprepare.h
mercurial/thirdparty/xdiff/xtypes.h
mercurial/thirdparty/xdiff/xutils.c
mercurial/thirdparty/xdiff/xutils.h
mercurial/thirdparty/zope/interface/_zope_interface_coptimizations.c