On Mon, 2 Apr 2012, Luca Porzio (lporzio) wrote: > > Great topics. As per one of Rik original points: > > > 4) skip writeout of zero-filled pages - this can be a big help > > for KVM virtual machines running Windows, since Windows zeroes > > out free pages; simply discarding a zero-filled page is not > > at all simple in the current VM, where we would have to iterate > > over all the ptes to free the swap entry before being able to > > free the swap cache page (I am not sure how that locking would > > even work) > > > > with the extra layer of indirection, the locking for this scheme > > can be trivial - either the faulting process gets the old page, > > or it gets a new one, either way it'll be zero filled > > > > Since it's KVMs realm here, can't KSM simply solve the zero-filled pages problem avoiding unnecessary burden for the Swap subsystem? I would expect that KSM already does largely handle this, yes. But it's also quite possible that I'm missing Rik's point. Hugh -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>