* Dave Hansen <dave@xxxxxxxxxxxxxxxxxx> [2010-06-14 10:09:31]: > On Mon, 2010-06-14 at 22:28 +0530, Balbir Singh wrote: > > If you've got duplicate pages and you know > > that they are duplicated and can be retrieved at a lower cost, why > > wouldn't we go after them first? > > I agree with this in theory. But, the guest lacks the information about > what is truly duplicated and what the costs are for itself and/or the > host to recreate it. "Unmapped page cache" may be the best proxy that > we have at the moment for "easy to recreate", but I think it's still too > poor a match to make these patches useful. > That is why the policy (in the next set) will come from the host. As to whether the data is truly duplicated, my experiments show up to 60% of the page cache is duplicated. The first patch today is again enabled by the host. Both of them are expected to be useful in the cache != none case. The data I have shows more details including the performance and overhead. -- Three Cheers, Balbir -- 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
