Fix deadlock with concurrent identical actions #2104
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Address issue TraceMachina#2001 where workers deadlock when numerous identical actions run simultaneously. Root causes and fixes: 1. File permit exhaustion: download_to_directory used unbounded parallelism. Added MAX_CONCURRENT_FILE_OPS=64 with buffer_unordered. 2. Race condition: create_and_add_action checked for duplicates AFTER async work. Added early registration with placeholder BEFORE async work. Fixes TraceMachina#2001
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All CI checks are now passing. Thanks for taking another look. @MarcusSorealheis |
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Address issue #2001 where workers deadlock when numerous identical actions run simultaneously.
Root causes and fixes
File permit exhaustion
download_to_directoryused unbounded parallelism, which could exhaust file permitsunder high concurrency. This is fixed by introducing
MAX_CONCURRENT_FILE_OPS = 64and switching tobuffer_unorderedto boundconcurrent file operations.
Race condition during action registration
create_and_add_actionchecked for duplicate actions after async work had begun,allowing identical actions to pass the check concurrently. This is fixed by
registering a placeholder entry before async work begins, with cleanup on failure,
ensuring duplicates are rejected deterministically.
Fixes #2001
Type of change
How has this been tested?
cargo checkcargo test download_to_directorynix develop(formatting, linting, Vale docs checks)Note: There is currently no test in the codebase that reproduces the exact concurrent
identical-action scenario described in #2001. This change addresses the identified
root causes deterministically.
Checklist
This change is