On Tue, Dec 02, 2014 at 11:11:18AM +0000, David Vrabel wrote: > On 01/12/14 22:36, Luis R. Rodriguez wrote: > > > > Then I do agree its a fair analogy (and find this obviously odd that how > > widespread cond_resched() is), we just don't have an equivalent for IRQ > > context, why not avoid the special check then and use this all the time in the > > middle of a hypercall on the return from an interrupt (e.g., the timer > > interrupt)? > > http://lists.xen.org/archives/html/xen-devel/2014-02/msg01101.html OK thanks! That explains why we need some asm code but in that submission you still also had used is_preemptible_hypercall(regs) and in the new implementation you use a CPU variable xen_in_preemptible_hcall prior to calling preempt_schedule_irq(). I believe you added the CPU variable because preempt_schedule_irq() will preempt first without any checks if it should, I'm asking why not do something like cond_resched_irq() where we check with should_resched() prior to preempting and that way we can avoid having to use the CPU variable? Luis -- 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
