On Mon, Aug 13, 2012 at 01:21:33PM +0300, Avi Kivity wrote: > On 08/13/2012 01:16 PM, Gleb Natapov wrote: > > On Mon, Aug 13, 2012 at 01:12:46PM +0300, Michael S. Tsirkin wrote: > >> On Mon, Aug 13, 2012 at 12:36:41PM +0300, Avi Kivity wrote: > >> > On 08/13/2012 12:16 PM, Gleb Natapov wrote: > >> > > Here is a quick prototype of what we discussed yesterday. This one > >> > > caches only MSI interrupts for now. The obvious problem is that not > >> > > all interrupts (namely IPIs and MSIs using KVM_CAP_SIGNAL_MSI) use irq > >> > > routing table, so they cannot be cached. > >> > > >> > We can have a small rcu-managed hash table to look those up. > >> > >> Yes but how small? We probably need at least one entry > >> per vcpu, no? > >> > > One entry? We will spend more time managing it than injecting interrupts > > :) ideally we need entry for each IPI sent and for each potential MSI > > from userspace. What happens when hash table is full? > > Drop the entire cache. > OK. Then it should be big enough to not do it frequently. > > We stop caching or > > invalidate old entries? If later then cache can go valid->invalid which > > may complicate the code. > > > > We can drop the entire cache via rcu freeing. In fact we can have a > closed hash allocated as a single blob, easy to manage. > That's what I am locking at doing, yes. -- Gleb. -- 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
