[PATCH] sched: use softirq for load balancing

[PATCH] sched: use softirq for load balancing

Call rebalance_tick (renamed to run_rebalance_domains) from a newly introduced
softirq.

We calculate the earliest time for each layer of sched domains to be rescanned
(this is the rescan time for idle) and use the earliest of those to schedule
the softirq via a new field "next_balance" added to struct rq.

Signed-off-by: Christoph Lameter <[email protected]>
Cc: Peter Williams <[email protected]>
Cc: Nick Piggin <[email protected]>
Cc: Christoph Lameter <[email protected]>
Cc: "Siddha, Suresh B" <[email protected]>
Cc: "Chen, Kenneth W" <[email protected]>
Acked-by: Ingo Molnar <[email protected]>
Cc: KAMEZAWA Hiroyuki <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>