sched: cgroup: Implement different treatment for idle shares (cd8ad40d) · Commits · 戴 / test

When setting the weight for a per-cpu task-group, we have to put in a phantom weight when there is no work on that cpu, otherwise we'll not service that cpu when new work gets placed there until we again update the per-cpu weights. We used to add these phantom weights to the total, so that the idle per-cpu shares don't get inflated, this however causes the non-idle parts to get deflated, causing unexpected weight distibutions. Reverse this, so that the non-idle shares are correct but the idle shares are inflated. Reported-by:

Yasunori Goto <y-goto@jp.fujitsu.com> Tested-by:

Yasunori Goto <y-goto@jp.fujitsu.com> Signed-off-by:

Peter Zijlstra <a.p.zijlstra@chello.nl> LKML-Reference: <1257934048.23203.76.camel@twins> Signed-off-by:

Ingo Molnar <mingo@elte.hu>

kernel/sched.c

+6 −2

Original line number	Diff line number	Diff line
		@@ -1614,7 +1614,7 @@ static void update_group_shares_cpu(struct task_group *tg, int cpu,
		*/
		static int tg_shares_up(struct task_group tg, void data)
		{
		unsigned long weight, rq_weight = 0, shares = 0;
		unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0;
		unsigned long *usd_rq_weight;
		struct sched_domain *sd = data;
		unsigned long flags;
		@@ -1630,6 +1630,7 @@ static int tg_shares_up(struct task_group tg, void data)
		weight = tg->cfs_rq[i]->load.weight;
		usd_rq_weight[i] = weight;

		rq_weight += weight;
		/*
		* If there are currently no tasks on the cpu pretend there
		* is one of average load so that when a new task gets to
		@@ -1638,10 +1639,13 @@ static int tg_shares_up(struct task_group tg, void data)
		if (!weight)
		weight = NICE_0_LOAD;

		rq_weight += weight;
		sum_weight += weight;
		shares += tg->cfs_rq[i]->shares;
		}

		if (!rq_weight)
		rq_weight = sum_weight;

		if ((!shares && rq_weight) \|\| shares > tg->shares)
		shares = tg->shares;

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