On Tue, 2012-05-01 at 15:12 +0300, Avi Kivity wrote: > > What's changed is not gup_fast() but the performance of munmap(), > exit(), and exec(), no? If it is indeed cache related like you suggested earlier, it would be the allocation side of things, like fork()/mmap() that suffer since there's fewer hot pages about, but yes, anything creating/destroying page-tables. > What bounds the amount of memory waiting to be freed during an rcu grace > period? Most RCU implementations don't have limits, so that could be quite a lot. I think preemptible RCU has a batch limit at which point it tries rather hard to force a grace period, but I'm not sure if even that provides a hard limit. Practically though, I haven't had reports of PPC/Sparc going funny because of this. -- 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
