On Fri, 8 Jun 2018, Liu, Chunmei wrote: > Hi Kefu, > > For RCU, I get the following facts, > 1. For readers, no block, and support multiple readers concurrently. > 2. For writers, it is blocked until all readers go out of reader-side critical session. If there are multiple concurrent writers need spin lock to synchronize all the writers. > > Are there multi concurrent writers for config or OSDMap? Not really... and for config writes are rare. I suspect we could even get away with something that just allocates each new value on the heap and updates a pointer, and then never bothers to free the old values. (Or maybe frees them after a ridiculous amount of time has passed.) For the OSDMap cache, we have a constant stream of new maps coming in and old maps getting pruned, so it's a bit trickier. > Do you think it is acceptable in seastar version since need spin lock > for multiple concurrent writers? > > Thanks! > -Chunmei > -- > To unsubscribe from this list: send the line "unsubscribe ceph-devel" in > the body of a message to majordomo@xxxxxxxxxxxxxxx > More majordomo info at http://vger.kernel.org/majordomo-info.html > >
