GOn Mon, Nov 25, 2013 at 04:29:28PM +0200, Gleb Natapov wrote: > On Mon, Nov 25, 2013 at 12:23:51PM -0200, Marcelo Tosatti wrote: > > On Mon, Nov 25, 2013 at 02:48:37PM +0200, Avi Kivity wrote: > > > On Mon, Nov 25, 2013 at 8:11 AM, Xiao Guangrong > > > <xiaoguangrong@xxxxxxxxxxxxxxxxxx> wrote: > > > > > > > > On Nov 23, 2013, at 3:14 AM, Marcelo Tosatti <mtosatti@xxxxxxxxxx> wrote: > > > > > > <snip complicated stuff about parent_pte> > > > > > > I'm not really following, but note that parent_pte predates EPT (and > > > the use of rcu in kvm), so all the complexity that is the result of > > > trying to pack as many list entries into a cache line can be dropped. > > > Most setups now would have exactly one list entry, which is handled > > > specially antyway. > > > > > > Alternatively, the trick of storing multiple entries in one list entry > > > can be moved to generic code, it may be useful to others. > > > > Yes, can the lockless list walking code be transformed into generic > > single-linked list walking? So the correctness can be verified > > independently, and KVM becomes a simple user of that interface. > > > The code will become simpler but the problem of never ending walk of > rculist_nulls will remain. Yes. Hopefully it can be fixed in some way. > > The simpler version is to maintain lockless walk on depth-1 rmap entries > > (and grab the lock once depth-2 entry is found). > And release it between each rmap walk or at the very end of write > protect? Or keep it locked until 10 consecutive sptes with depth 1 are found. -- 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
