Hi! > > > So, this means, on suspend(): > > > > > > 1. Don't worry about TASK_UNINTERRUPTIBLE > > > 2. Do worry about TASK_INTERRUPTIBLE > > > We have to cease IO and must not call wake_up_interruptible() > > > > "cease IO"? No, I believe it is enough not to start new I/O. Userspace > > is frozen at that point, it can't ask you to do I/O. > > > > > Isn't that a race until suspend() is called? > > > > I do not think so. > > What about URBs in flight which are waited for with TASK_INTERRUPTIBLE? Same thing as if someone sent a signal to that process. (We are talking about user processes here, right? Kernel threads have to take care themselves). > > > On resume(): > > > > > > 1. Don't worry about TASK_UNINTERRUPTIBLE > > > 2. Do not restart IO that may call wake_up_interruptible() > > > > > > When do we restart such IO? > > > > We reuse signal handling code to do that for us. It is same situation > > as when someone signals task doing I/O. > > What happens to tasks in TASK_INTERRUPTIBLE which are frozen? > Are they interrupted and frozen? Interrupted with fake signal, then frozen, yes. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
