On Mon, Aug 27, 2012 at 05:28:35PM -0300, Rafael Aquini wrote: > On Sun, Aug 26, 2012 at 10:55:58AM +0300, Michael S. Tsirkin wrote: > > On Sat, Aug 25, 2012 at 02:24:56AM -0300, Rafael Aquini wrote: > > > Memory fragmentation introduced by ballooning might reduce significantly > > > the number of 2MB contiguous memory blocks that can be used within a guest, > > > thus imposing performance penalties associated with the reduced number of > > > transparent huge pages that could be used by the guest workload. > > > > > > This patch introduces a common interface to help a balloon driver on > > > making its page set movable to compaction, and thus allowing the system > > > to better leverage the compation efforts on memory defragmentation. > > > > > > Signed-off-by: Rafael Aquini <aquini@xxxxxxxxxx> > > > > Tons of rcu uses but not sync in sight. This looks suspicious. > > There's no critical section marked with rcu_read_lock/rcu_read_unlock. that's > why there's no call for sync anywhere. As we are behaving mostly as updaters, > the hole rcu usage is awkward and it's placed basically to enforce the proper > order. To avoid hurting the RCU API usage with this awk approach I'll drop it > for the next series submission (it will use barriers instead). If everything is under page lock, barriers are likely not required. If not, they might not be sufficient. -- MST -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>