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Commit d3f40dba authored by Peter Zijlstra's avatar Peter Zijlstra Committed by Ingo Molnar
Browse files

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: default avatarPeter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Cc: Mike Galbraith <efault@gmx.de>
Signed-off-by: default avatarIngo Molnar <mingo@elte.hu>
parent 53fecd8a

kernel/sched.c

+3 −23
Original line number Diff line number Diff line
@@ -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;

	}

}



/*