sched: dont micro manage share losses

We used to try and contain the loss of 'shares' by playing arithmetic
games. Replace that by noticing that at the top sched_domain we'll
always have the full weight in shares to distribute.

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>
This commit is contained in:
Peter Zijlstra 2008-06-27 13:41:21 +02:00 committed by Ingo Molnar
parent 53fecd8ae1
commit d3f40dbab9

View File

@ -1551,6 +1551,9 @@ aggregate_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd)
if ((!shares && aggregate(tg, cpu)->rq_weight) || shares > tg->shares)
shares = tg->shares;
if (!sd->parent || !(sd->parent->flags & SD_LOAD_BALANCE))
shares = tg->shares;
aggregate(tg, cpu)->shares = shares;
}
@ -1642,20 +1645,8 @@ static void
__move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd,
int scpu, int dcpu)
{
unsigned long shares;
shares = tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares;
__update_group_shares_cpu(tg, cpu, sd, scpu);
__update_group_shares_cpu(tg, cpu, sd, dcpu);
/*
* ensure we never loose shares due to rounding errors in the
* above redistribution.
*/
shares -= tg->cfs_rq[scpu]->shares + tg->cfs_rq[dcpu]->shares;
if (shares)
tg->cfs_rq[dcpu]->shares += shares;
}
/*
@ -1675,7 +1666,6 @@ move_group_shares(struct task_group *tg, int cpu, struct sched_domain *sd,
static void
aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *sd)
{
unsigned long shares = aggregate(tg, cpu)->shares;
int i;
for_each_cpu_mask(i, sd->span) {
@ -1688,16 +1678,6 @@ aggregate_group_set_shares(struct task_group *tg, int cpu, struct sched_domain *
}
aggregate_group_shares(tg, cpu, sd);
/*
* ensure we never loose shares due to rounding errors in the
* above redistribution.
*/
shares -= aggregate(tg, cpu)->shares;
if (shares) {
tg->cfs_rq[cpu]->shares += shares;
aggregate(tg, cpu)->shares += shares;
}
}
/*