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Commit cd8ad40de36c2fe75f3b731bd70198b385895246

Authored by Peter Zijlstra
Committed by Ingo Molnar
1 parent fb58bac5c7
Exists in master and in 7 other branches imx_3.0.35_4.1.0, imx_3.10.17_1.0.1_ga, imx_3.10.53_1.1.0_ga, imx_3.14.28_1.0.0_ga, smarc-imx_3.10.53_1.1.0_ga, smarc-imx_3.14.28_1.0.0_ga, smarc-l5.0.0_1.0.0-ga

sched: cgroup: Implement different treatment for idle shares 

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>

Showing 1 changed file with 6 additions and 2 deletions Side-by-side Diff

... ... @@ -1614,7 +1614,7 @@
1614 1614 */
1615 1615 static int tg_shares_up(struct task_group *tg, void *data)
1616 1616 {
1617   - unsigned long weight, rq_weight = 0, shares = 0;
  1617 + unsigned long weight, rq_weight = 0, sum_weight = 0, shares = 0;
1618 1618 unsigned long *usd_rq_weight;
1619 1619 struct sched_domain *sd = data;
1620 1620 unsigned long flags;
... ... @@ -1630,6 +1630,7 @@
1630 1630 weight = tg->cfs_rq[i]->load.weight;
1631 1631 usd_rq_weight[i] = weight;
1632 1632  
  1633 + rq_weight += weight;
1633 1634 /*
1634 1635 * If there are currently no tasks on the cpu pretend there
1635 1636 * is one of average load so that when a new task gets to
1636 1637  
... ... @@ -1638,9 +1639,12 @@
1638 1639 if (!weight)
1639 1640 weight = NICE_0_LOAD;
1640 1641  
1641   - rq_weight += weight;
  1642 + sum_weight += weight;
1642 1643 shares += tg->cfs_rq[i]->shares;
1643 1644 }
  1645 +
  1646 + if (!rq_weight)
  1647 + rq_weight = sum_weight;
1644 1648  
1645 1649 if ((!shares && rq_weight) || shares > tg->shares)
1646 1650 shares = tg->shares;