Messages in this thread Patch in this message | | | Date | Fri, 06 Aug 2010 11:56:56 -0700 | From | Greg KH <> | Subject | [01/34] sched: cgroup: Implement different treatment for idle shares |
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2.6.32-stable review patch. If anyone has any objections, please let us know.
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From: Peter Zijlstra <a.p.zijlstra@chello.nl>
commit cd8ad40de36c2fe75f3b731bd70198b385895246 upstream.
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> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
--- kernel/sched.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-)
--- a/kernel/sched.c +++ b/kernel/sched.c @@ -1623,7 +1623,7 @@ static void update_group_shares_cpu(stru */ 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; @@ -1639,6 +1639,7 @@ static int tg_shares_up(struct task_grou 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 @@ -1647,10 +1648,13 @@ static int tg_shares_up(struct task_grou 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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