On Wed, 19 Feb 2025 18:55:31 -0500 Steven Rostedt <rostedt@xxxxxxxxxxx> wrote: > On Thu, 20 Feb 2025 07:56:39 +0900 > Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx> wrote: > > > > >> this field, we don't need to take lock, though taking the wait_lock may > > > >> still be needed to examine other information inside the mutex. > > > > Do we need to take it just for accessing owner, which is in an atomic? > > Updating the task_struct would be in the same location as the blocked_on is > anyway. I would make it into a wrapper function that is a nop when disabled. Should we make it depends on DEBUG_MUTEXES too? I think no. We can introduce a different kconfig and wrapper function which calls debug_mutex_*(). > > > > > > > But perhaps if we add a new config option for this feature, we could just > > > > add the lock that a task is blocked on before it goes to sleep and > > > > reference that instead. That would be easier than trying to play games > > > > getting the lock owner from the blocked_on field. > > > > > > Yes, it could be a new config option. This will be a useful feature that > > > I believe most distros will turn it on. Or we may just include that in > > > the core code without any option. > > > > Do we need another option? or just extend DETECT_HUNG_TASK? > > DETECT_HUNG_TASK is just that, for detecting hung tasks. This adds more > information to that, which increases the size of the task_struct not to > mention adds code in the mutex/rwsem handlers. > > I would definitely make it a separate config that may depend on > DETECT_HUNG_TASK. OK, what about CONFIG_TASK_BLOCKER? Thank you, > > -- Steve > -- Masami Hiramatsu (Google) <mhiramat@xxxxxxxxxx>
