sched: kill task_group balancing (53fecd8a) · Commits · 戴 / test

The idea was to balance groups until we've reached the global goal, however Vatsa rightly pointed out that we might never reach that goal this way - hence take out this logic. [ the initial rationale for this 'feature' was to promote max concurrency within a group - it does not however affect fairness ] Reported-by:

Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Signed-off-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com> Cc: Mike Galbraith <efault@gmx.de> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

kernel/sched_fair.c

+2 −13

Original line number	Diff line number	Diff line
		@@ -1422,9 +1422,7 @@ load_balance_fair(struct rq this_rq, int this_cpu, struct rq busiest,

		rcu_read_lock();
		list_for_each_entry(tg, &task_groups, list) {
		long imbalance;
		unsigned long this_weight, busiest_weight;
		long rem_load, max_load, moved_load;
		long rem_load, moved_load;

		/*
		* empty group
		@@ -1435,17 +1433,8 @@ load_balance_fair(struct rq this_rq, int this_cpu, struct rq busiest,
		rem_load = rem_load_move * aggregate(tg, this_cpu)->rq_weight;
		rem_load /= aggregate(tg, this_cpu)->load + 1;

		this_weight = tg->cfs_rq[this_cpu]->task_weight;
		busiest_weight = tg->cfs_rq[busiest_cpu]->task_weight;

		imbalance = (busiest_weight - this_weight) / 2;

		if (imbalance < 0)
		imbalance = busiest_weight;

		max_load = max(rem_load, imbalance);
		moved_load = __load_balance_fair(this_rq, this_cpu, busiest,
		max_load, sd, idle, all_pinned, this_best_prio,
		rem_load, sd, idle, all_pinned, this_best_prio,
		tg->cfs_rq[busiest_cpu]);

		if (!moved_load)

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