Rob van der Heij wrote: > So what options does z/VM have then when you overcommit resources and > suddenly everyone comes to get his share? Limit the working set size of the guest, and thereby throttle it.
> Should CP randomly force > virtual machines off the system so that people not just *think* it has > crashed? (just like Linux kill processes when you run out of swap > space). In this situation, z/VM does not run out of paging space as far as I see. > If it were just for CPU resources, it might help to guarantee a > minimum amount of cycles to keep the guest operating system alive (but > can we be sure it would be used for that). But when the virtual > machine also needs a lot of pages resident to consume those cycles, > then CP would spend more time rushing pages in and out. But similar to cpu, CP could set a minimal set of pages resident. > Maybe it would be nice if CP could put the guest in some "power saving > mode" where we know that it will only use resources required to avoid > bigger damage. How about when Linux would run those emergency tasks > only on a specific virtual CPU so that CP can tell that work is > important? By using sched_setaffinity [see man page] you can bind processes to CPUs if you want to. How would Linux tell what work is "important" for you? Usually load-balancing over CPUs is what people want. -- Carsten Otte IBM Linux technology center ARCH=s390 ---------------------------------------------------------------------- For LINUX-390 subscribe / signoff / archive access instructions, send email to [EMAIL PROTECTED] with the message: INFO LINUX-390 or visit http://www.marist.edu/htbin/wlvindex?LINUX-390
