On Fri, Jan 08, 2021 at 08:13:25AM -0700, Jens Axboe wrote: > > Anyway, bedtime for me; right now it looks like at least for task == > > current we always want TWA_SIGNAL. I'll look into that more tomorrow > > when I get up, but so far it smells like switching everything to > > TWA_SIGNAL would be the right thing to do, if not going back to bool > > notify for task_work_add()... > > Before the change, the fact that we ran task_work off get_signal() and > thus processed even non-notify work in that path was a bit of a mess, > imho. If you have work that needs processing now, in the same manner as > signals, then you really should be using TWA_SIGNAL. For this pipe case, > and I'd need to setup and reproduce it again, the task must have a > signal pending and that would have previously caused the task_work to > run, and now it does not. TWA_RESUME technically didn't change its > behavior, it's still the same notification type, we just don't run > task_work unconditionally (regardless of notification type) from > get_signal(). It sure as hell did change behaviour. Think of the effect of getting hit with SIGSTOP. That's what that "bit of a mess" had been about. Work done now vs. possibly several days later when SIGCONT finally gets sent. > I think the main question here is if we want to re-instate the behavior > of running task_work off get_signal(). I'm leaning towards not doing > that and ensuring that callers that DO need that are using TWA_SIGNAL. Can you show the callers that DO NOT need it?
