tzhouamandClaude Fable 5.1
4e3e8a1ebc
Verbatim copy of the edge/omni-edge working tree (tracked diffs + untracked edge/local, tests/edge/local, docs/edge, pipeline files). Taken so that vLLM-Omni v0.29.0rc1 can be merged on a branch without touching the user's working tree. logs_edge/ and benchmark .npy outputs excluded. Co-Authored-By: Claude Fable 5.1 <noreply@anthropic.com>
70 lines
2.5 KiB
Python
Executable File
70 lines
2.5 KiB
Python
Executable File
# SPDX-License-Identifier: Apache-2.0
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# SPDX-FileCopyrightText: Copyright contributors to the vLLM-Omni project
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"""Non-blocking exclusive file locks, on POSIX and on Windows.
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[edge-infer W1] ``vllm_omni.engine.stage_init_utils`` imports ``fcntl`` at module
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scope for the device-initialization lock. ``fcntl`` does not exist on Windows, and
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because that module is in the import closure of ``AsyncOmni`` the import fails
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before anything can be configured. The locking *logic* is sound and already
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torch-free; only the primitive has to change.
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Two behavioural differences are deliberate and worth knowing:
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* ``flock`` is advisory and whole-file; ``msvcrt.locking`` is mandatory and
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byte-range. We therefore lock **one byte at a fixed high offset**, far past the
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PID text the caller writes, so the lock never overlaps the data. Locking byte 0
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instead would make the caller's own ``ftruncate``/``write`` fail on Windows.
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* ``msvcrt.locking`` raises ``OSError`` when the region is already held, where
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``flock`` raises ``BlockingIOError``. This module normalizes to
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``BlockingIOError`` so the caller's existing ``except BlockingIOError`` branch
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-- which is what triggers stale-lock cleanup -- keeps working untouched.
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Both flavours release on process death, which is what the stale-lock path relies
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on: POSIX ``flock`` by the kernel dropping the fd, Windows by the file handle
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closing when the process exits.
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"""
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from __future__ import annotations
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import os
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_WINDOWS = os.name == "nt"
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# Far beyond any PID line the caller writes, so the locked byte and the file
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# contents never overlap.
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_LOCK_OFFSET = 1 << 30
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if _WINDOWS:
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import msvcrt
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def flock_exclusive_nb(fd: int) -> None:
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"""Take an exclusive, non-blocking lock. Raises BlockingIOError if held."""
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here = os.lseek(fd, 0, os.SEEK_CUR)
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os.lseek(fd, _LOCK_OFFSET, os.SEEK_SET)
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try:
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msvcrt.locking(fd, msvcrt.LK_NBLCK, 1)
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except OSError as exc:
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raise BlockingIOError(str(exc)) from exc
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finally:
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os.lseek(fd, here, os.SEEK_SET)
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def funlock(fd: int) -> None:
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here = os.lseek(fd, 0, os.SEEK_CUR)
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os.lseek(fd, _LOCK_OFFSET, os.SEEK_SET)
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try:
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msvcrt.locking(fd, msvcrt.LK_UNLCK, 1)
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finally:
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os.lseek(fd, here, os.SEEK_SET)
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else:
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import fcntl
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def flock_exclusive_nb(fd: int) -> None:
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fcntl.flock(fd, fcntl.LOCK_EX | fcntl.LOCK_NB)
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def funlock(fd: int) -> None:
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fcntl.flock(fd, fcntl.LOCK_UN)
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__all__ = ["flock_exclusive_nb", "funlock"]
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