On 03/26/2012 02:25 PM, Peter Zijlstra wrote:
On Mon, 2012-03-26 at 19:45 +0200, Andrea Arcangeli wrote:@@ -3220,6 +3214,8 @@ need_resched: post_schedule(rq); + sched_autonuma_balance(); + sched_preempt_enable_no_resched(); if (need_resched()) goto need_resched;I already told you, this isn't ever going to happen. You do _NOT_ put a for_each_online_cpu() loop in the middle of schedule().
Agreed, it looks O(N), but because every CPU will be calling it its behaviour will be O(N^2) and has the potential to completely break systems with a large number of CPUs. Finding a lower overhead way of doing the balancing does not seem like an unsurmountable problem.
You also do not call stop_one_cpu(migration_cpu_stop) in schedule to force migrate the task you just scheduled to away from this cpu. That's retarded. Nacked-by: Peter Zijlstra<a.p.zijlstra@xxxxxxxxx>
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