On Thu, Jun 23, 2011 at 8:00 AM, Rik van Riel <riel@xxxxxxxxxx> wrote: > On 06/22/2011 07:37 PM, Nai Xia wrote: > >> On 2MB pages, I'd like to remind you and Rik that ksmd currently splits >> huge pages before their sub pages gets really merged to stable tree. > > Your proposal appears to add a condition that causes ksmd to skip > doing that, which can cause the system to start using swap instead > of sharing memory. Hmm, yes, no swapping. So we should make the checksum default for huge pages, right? > >> So when there are many 2MB pages each having a 4kB subpage >> changed for all time, this is already a concern for ksmd to judge >> if it's worthwhile to split 2MB page and get its sub-pages merged. >> I think the policy for ksmd in a system should be "If you cannot do sth >> good, >> at least do nothing evil". So I really don't think we can satisfy _all_ >> people. >> Get a general method and give users one or two knobs to tune it when they >> are the corner cases. How do you think of my proposal ? > > I think your proposal makes sense for 4kB pages, but the ksmd > policy for 2MB pages probably needs to be much more aggressive. I now agree with you on the whole point. Let's fall back to checksum Thanks for make my mind clear! :) And shall we provide a interface to users if he _really_ what to judge the dirty bit from the pmd level? I think we should agree to one point before I misunderstand you and spam you with my next submission :P And thanks for your time viewing! -Nai > > -- > All rights reversed > -- 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
