On Mon, Aug 23, 2010 at 08:38:25AM -0500, Christoph Lameter wrote: > On Mon, 23 Aug 2010, Mel Gorman wrote: > > > > The maximum time for which the livelock can exists is the vm stat > > > interval. By default the counters are brought up to date at least once per > > > second or if a certain delta was violated. Drifts are controlled by the > > > delta configuration. > > > > > > > While there is a maximum time (2 seconds I think) the drift can exist > > in, a machine under enough pressure can make a mess of the watermarks > > during that time. If it wasn't the case, these livelocks with 0 pages > > free wouldn't be happening. > > So because we go way beyond the watermarks we reach a state in which a > livelock exists that does not go away when the counters are finally > updated? > That appears to be the case. The system has already gotten into a state where there are 0 pages free. Just because the NR_FREE_PAGES counter gets updated to reflect the accurate count of 0 does not mean the system can recover from it. -- Mel Gorman Part-time Phd Student Linux Technology Center University of Limerick IBM Dublin Software Lab -- 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>