On Wed, 29 Sep 2010, Mel Gorman wrote: > > The threshold is stored in the hot part of the per cpu page structure. > > > > And the consequences of moving it? In terms of moving, it would probably > work out better to move percpu_drift_mark after the lowmem_reserve and > put the threshold after it so they're at least similarly hot across > CPUs. If you move it then the cache footprint of the vm stat functions (which need to access the threshold for each access!) will increase and the performance sink dramatically. I tried to avoid placing the threshold there when I developed that approach but it always caused a dramatic regression under heavy load. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>