From cd8ad40de36c2fe75f3b731bd70198b385895246 Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Thu, 3 Dec 2009 18:00:07 +0100 Subject: [PATCH] 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 Tested-by: Yasunori Goto Signed-off-by: Peter Zijlstra LKML-Reference: <1257934048.23203.76.camel@twins> Signed-off-by: Ingo Molnar --- kernel/sched.c | 8 ++++++-- 1 file changed, 6 insertions(+), 2 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index 0170735..71eb062 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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; -- 2.7.4