On Sat, 3 Feb 2007, Davide Libenzi wrote: > > - Signals. I have no idea what behaviour we want. Help? My first guess is > > that we'll want signal state to be shared by fibrils by keeping it in the > > task_struct. If we want something like individual cancellation, we'll > > augment > > signal_pending() with some some per-fibril test which will cause it to > > return > > from TASK_INTERRUPTIBLE (the only reasonable way to implement generic > > cancellation, I'll argue) as it would have if a signal was pending. > > Fibril should IMO use current thread signal policies. I think a signal > should hit (wake) any TASK_INTERRUPTIBLE fibril, if the current thread > policies mandate that. I'd keep a list_head of currently scheduled-out > TASK_INTERRUPTIBLE fibrils, and I'd make them runnable when a signal is > delivered to the thread (wake_target bit #1 set to mean > wake-all-interruptable-fibrils?). > The other thing is signal_pending(). The sigpending flag test is not going > to work as is (cleared at the first do_signal). Setting a bit in each > fibril would mean walking the whole TASK_INTERRUPTIBLE fibril list. Maybe > a sequential signal counter in task_struct, matched by one in the fibril. > A signal would increment the task_struct counter, and a fibril > schedule-out would save the task_struct counter to the fibril. The > signal_pending() for a fibril is a compare of the two. Or something > similar.
Another thing linked to signals that was not talked about, is cancellation of an in-flight request. We want to give the ability to cancel an in-flight request, with something like async_cancel(cookie). In my userspace library I simply disable SA_RESTART of SIGUSR2, and I do a pthread_kill() on the thread servicing the request. But this will IMO have other implications (linked to signal delivery) in a kernel fibril-based implementation, to think about it. - Davide - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
