On Mon, Jul 22, 2019 at 11:14:39AM -0400, Joel Fernandes wrote: > [snip] > > > Would it make sense to have call_rcu() check to see if there are many > > > outstanding requests on this CPU and if so process them before returning? > > > That would ensure that frequent callers usually ended up doing their > > > own processing. > > Other than what Paul already mentioned about deadlocks, I am not sure if this > would even work for all cases since call_rcu() has to wait for a grace > period. > > So, if the number of outstanding requests are higher than a certain amount, > then you *still* have to wait for some RCU configurations for the grace > period duration and cannot just execute the callback in-line. Did I miss > something? > > Can waiting in-line for a grace period duration be tolerated in the vhost case? > > thanks, > > - Joel No, but it has many other ways to recover (try again later, drop a packet, use a slower copy to/from user). -- MST
