>> Doesn't KSM notifies KVM about the shared pages so that KVM can update >> its sptes accordingly or is it done by KSM itself ? >> > > when using kvm, mmu notifiers is a must for ksm, (mmu notifiers update kvm > about the changes in the host page table) > >> What about KSM being used by someone other than KVM ? Does KSM updates >> the ptes of the shared pages itself ? >> > > it can be used by any application, it update the ptes of the host, what you > mean by the shared pages itself?
by "itself" I meant 'ksm'. So ksm will take care of updating the ptes of the shared guest pages. > >> >> >>>> >>>> Where are the shared pages kept ? In kernel memory ? Aren't the shared >>>> pages always pinned in RAM (due to same reasons for pinned shadowed >>>> pages) ? >>>> >>>> >>> >>> in the version that was sent to the list it was kernel memory (meaning >>> shared pages are not swappable >>> (just the pages that are shared not the pages that we scan, when they are >>> split beacuse of copy on write it become swappable again >>> new version that i will send soon the pages are normal >>> anonymous/userspace >>> memory that is swappable >>> >>> >> >> What is the strategy/method which you will use to represent the shared >> memory as normal anonymous/userspace memory ? Then, these pages must >> be staying at one of the guest's address-space (whose pages have been >> shared) ? >> > > > it possible due to another patch that i need to send, that allow modules > register new reverse mapping call backs..., > ok but in whose address-space will these shared pages stay ? >> >> >>>> >>>> How much is the overhead involved due to this ? >>>> >>>> >>> >>> depeand on the speed you tell it to scan, but the overhead is about ~5% >>> for >>> common cases >>> >> >> Can I know the typical values of the parameters : sleep time, no. of >> pages to scan, which you used to arrive at the above mentioned >> overhead. >> > > i think it is about 256 2000 (256 pages per 2000 usleep) > (note that most of the cpu is acutlay taken by the copying of the pages when > a new shared page is created, i have possible way to change it and reduce > the cpu even more > but i dont know if i want to do it) (it add more IFs to the fast path inside > the mm) > > >> >> > > Thanks :) -- Regards, Sukanto Ghosh -- To unsubscribe from this list: send the line "unsubscribe kvm" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html
