2012/11/28 Gleb Natapov <gleb@xxxxxxxxxx>: > On Wed, Nov 28, 2012 at 01:55:42PM +0100, Frederic Weisbecker wrote: >> Yes but if rcu_irq_*() calls are fine to be called there, and I >> believe they are because exception_enter() exits the user mode, we >> should start to protect there right now instead of waiting for a >> potential future warning of illegal RCU use. >> > Async page not present is not much different from regular page fault > exception when it happens not on idle task (regular #PF cannot happen > on idle task), but code have a special handling for idle task. So why > do you think rcu_irq_*() is required here, but not in page fault > handler? Because we are not supposed to fault in idle, at least I hope there are no case around. Except on cases like here with KVM I guess but we have that special async handler for that. Note exception_enter() only takes cares of RCU user mode, not idle. If the need arise in the future we can extend it to handle idle. >> > >> > I think we still need Gleb's patch about the idle check in >> > kvm_async_pf_task_wait(), and maybe another patch for the >> > exit_idle()/enter_idle() issue. >> >> Right. >> > Done. Thanks! -- To unsubscribe from this list: send the line "unsubscribe linux-next" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
