On Tue, Jun 16, 2009 at 10:40:55AM -0400, Gregory Haskins wrote: > > This is ugly, isn't it? With CONFIG_PREEMPT=no preemptible() is always false. > > > > Further, to do useful things it might not be enough that you can sleep: > > with iofd you also want to access current task with e.g. copy from user. > > > > Something else to consider: For iosignalfd, we can assume we will > always be called from vcpu process context so we might not really need > official affirmation from the system. For irqfd, we cannot predict who > may be injecting the interrupt (for instance, it might be a > PCI-passthrough hard-irq context). I am not sure if this knowledge > actually helps to simplify the problem space, but I thought I should > mention it. > > -Greg > > The way this is addressed with eventfd_signal_task proposal is: - user calls eventfd_signal_task we look at current->mm and figure out whether this is the right context or we need a context switch - everyone else calls eventfd_signal we know that we need a context switch -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
