> > signalfd is a special descriptor, so I think it > > is not a big deal, that it works a bit strange. > > Sure, but the more we special case things, the uglier the ABI as a > whole becomes. So special casing should be avoided as far as we can. > > > If all other would > > decides, that a new syscall is better, I will not ague. > > And that's more or less how I see it too. I'm not going to argue for a > new syscall, based on what I know so far. > > Here is one idea to think about though, while more or less maintaining > your proposed interface. > > At the moment, you select signal queues in the pread() call. An > alternative would be to do it in the signalfd() call. In other words, > you could have the following flags used with signalfd() > > SFD_RAW > SFD_SHARED_QUEUE -- reads will be from process-wide shared signal queue > SFD_PER_THREAD_QUEUE --reads will be from per-thread signal queue I suggested this variant in the initial series, but then we decided to avoid adding new flags. Oleg, what do you think about this? > > Specifying both SFD_SHARED_QUEUE and SFD_PER_THREAD_QUEUE would be > the same as omitting them both, providing the default behavior of > slecting from both queues. > > My point here is that you can then separate the RAW functionality from > the queue selector functionality. Now, it might be that at the moment > you always require that if the caller specifies SFD_SHARED_QUEUE or > SFD_PER_THREAD_QUEUE, then they must also specify SFD_RAW. But later, > that constraint might be relaxed, so that users could use signalfd() > to select from a particular queue when reading traditional (non-RAW) > signalfd_siginfo structures from a signalfd. I am not sure, that you understood this moment correctly. Currently SFD_RAW is independent on SFD_*_QUEUE. If signalfd is created without SFD_RAW, pread returns signalfd_siginfo-s. If SFD_RAW is set, read returns siginfo_t-s. One more point for two flags is that we will be able to choose a queue from which signals will be dequeued. Currently we can choose a queue only for pread. Thanks > This does seem like a > very sensible design optimization to make now (and an easy one, I > would suppose). What do you think? > > Cheers, > > Michael -- To unsubscribe from this list: send the line "unsubscribe linux-fsdevel" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
