ceph::mutex is a new type that's intended to replace use of the legacy Mutex (pthreads mutex wrapper) and also direct use of std::mutex. - For debug builds, ceph::mutex is an alias for ceph::mutex_debug, which is a Mutex-like implementation from Adam that wraps pthreads and wires into lockdep--but is also conformant with the Lockable concept. Similarly, ceph::condition_variable is ceph::condition_variable_debug, which works with mutex_debug and adds various asserts (taken from Mutex and Cond) to catch some common patterns of mutex/cond misuse. This 'debug' mode is enabled for the notcmalloc shaman builds. - For release builds, ceph::mutex etc alias directly to std::mutex so there is no overhead. - do_cmake.sh is updated to -DCMAKE_BUILD_TYPE=Debug by default. This means you get the debug ceph::mutex version (that does lockdep). It also means optimizations are turned down so you can gdb through core files with less pain from symbols optimized away. :) - The only code that has been converted to ceph::mutex so far is Finisher. You can see what that transition looks like here: https://github.com/ceph/ceph/pull/24133/commits/8535965ba4298537c489897ccb191a0f458d60d7 - lock("Foo::lock") -> lock(ceph::make_mutex("Foo::lock")) in ctor - Lock() -> lock(), Unlock() -> unlock(), etc. - Mutex::Locker l(lock) -> unique_lock l(lock) (or lock_guard) - cond.Signal() -> cond.notify_all() Everything is now in place to make these changes across the rest of the code. I suggest doing this subsystem by subsystem to minimize merge conflicts and so that each component can independently sequence it through their testing, resolve conflicts, etc. sage
