Cheng Shao pushed to branch wip/rts-mutex-static-initializer at Glasgow Haskell Compiler / GHC Commits: c2d9398a by Cheng Shao at 2025-12-12T01:41:00+01:00 rts: replace initMutex/closeMutex with static initializer This patch drops all `initMutex`/`closeMutex` logic from the RTS, and instead define and use a static initializer `MUTEX_INIT` to initialize a `Mutex`. For both pthreads/win32 cases, a mutex is just a process-private cheap resource that doesn't really need to be freed upon RTS exit; it can be statically initialized inplace using either `PTHREAD_MUTEX_INITIALIZER` or `SRWLOCK_INIT`, hence we define `MUTEX_INIT` and prefer to use it to initialize a `Mutex`. All `closeMutex` invocations are dropped. Most `initMutex` invocations are dropped, except non-global ones, and the ones that need to be re-initialized in the child process after `forkProcess`, these are replaced by assigning `MUTEX_INIT`. The patch also drops `initIpe`/`exitIpe`/`stat_exit` since they are now no-ops. Also cleans up legacy wasm32 stub definitions, since wasi-libc started shipping basic pthread stubs in wasip1 sysroot. Sadly, we can't do the same for condition variables, since `PTHREAD_COND_INITIALIZER` defaults to real-time but we want monotonic time. The main motivation of this patch is not just housecleaning: it is to make it easier to acquire/release a global Mutex in C initializer functions generated by GHC (some custom instrumentation for debugging purpose). Now that a global Mutex can be statically initialized in-place using `MUTEX_INIT`, the initializer code can acquire/release it without worrying about Mutex initialization, otherwise it needs to be initialized in another initializer function with higher priority, which complicates the implementation. Co-authored-by: Codex - - - - - 34 changed files: - rts/Capability.c - rts/FileLock.c - rts/Globals.c - rts/IPE.c - rts/IPE.h - rts/Linker.c - rts/Pool.c - rts/Profiling.c - rts/RtsStartup.c - rts/Schedule.c - rts/StableName.c - rts/StablePtr.c - rts/StaticPtrTable.c - rts/Stats.c - rts/Stats.h - rts/Task.c - rts/TopHandler.c - rts/Trace.c - rts/adjustor/AdjustorPool.c - rts/eventlog/EventLog.c - rts/eventlog/EventLogWriter.c - rts/include/rts/OSThreads.h - rts/posix/OSThreads.c - rts/posix/Signals.c - rts/posix/ticker/Pthread.c - rts/posix/ticker/TimerFd.c - rts/sm/GC.c - rts/sm/NonMoving.c - rts/sm/NonMovingMark.c - rts/sm/Storage.c - rts/win32/OSThreads.c - rts/win32/ThrIOManager.c - testsuite/tests/ffi/should_run/IncallAffinity_c.c - testsuite/tests/rts/RestartEventLogging_c.c The diff was not included because it is too large. View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c2d9398a059ea7487f18488d8aac813b... -- View it on GitLab: https://gitlab.haskell.org/ghc/ghc/-/commit/c2d9398a059ea7487f18488d8aac813b... You're receiving this email because of your account on gitlab.haskell.org.