From d3f40dbab954d83383b6a516582d5c09cc216dcc Mon Sep 17 00:00:00 2001 From: Peter Zijlstra Date: Fri, 27 Jun 2008 13:41:21 +0200 Subject: [PATCH] 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 Cc: Srivatsa Vaddagiri Cc: Mike Galbraith Signed-off-by: Ingo Molnar --- kernel/sched.c | 26 +++----------------------- 1 file changed, 3 insertions(+), 23 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index dae20199dc..28229c5d49 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -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; - } } /* -- 2.39.5