From: "Dinakar Guniguntala" <[EMAIL PROTECTED]>
Can we hold on to this patch for a while, as I reported yesterday, this hangs up my ppc64 box on doing rmdir on a exclusive cpuset. Still debugging the problem, hope to have a fix soon, Thanks
Paul's patch simply constrains the scope of cpuset configurations that will invoke the "dynamic sched domains" functionality, which means that some cpu-exclusive (a.k.a. "isolated") cpusets will continue to have the 2.6.12-and-earlier behavior of being periodically examined by the CPU Scheduler in load-balancing activities. That is, Paul's patch simply reverts cpuset/sched domain behavior to pre-2.6.13 status (for some cpusets).
The pre-2.6.13 non-"dynamic sched domains" behavior will in fact produce bad load-balancing behavior if a cpu-exclusive cpuset is so heavily loaded with executing processes, all pinned to the cpu(s) in the cpuset, that the other cpus in the system see this cpu(s)/node as the most-heavily-loaded and just focus on it during load-balancing -- which would be futile, of course, since the processes pinned to this highest-load cpu (and node) cannot be offloaded. Since load-balancing looks only at the most-heavily-loaded cpu as a cpu to offload, this means that all system load-balancing would be effectively turned off.
John Hawkes
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