From 953bfcd10e6f3697233e8e5128c611d275da39c1 Mon Sep 17 00:00:00 2001 From: Paul Turner Date: Thu, 21 Jul 2011 09:43:27 -0700 Subject: sched: Implement hierarchical task accounting for SCHED_OTHER Introduce hierarchical task accounting for the group scheduling case in CFS, as well as promoting the responsibility for maintaining rq->nr_running to the scheduling classes. The primary motivation for this is that with scheduling classes supporting bandwidth throttling it is possible for entities participating in throttled sub-trees to not have root visible changes in rq->nr_running across activate and de-activate operations. This in turn leads to incorrect idle and weight-per-task load balance decisions. This also allows us to make a small fixlet to the fastpath in pick_next_task() under group scheduling. Note: this issue also exists with the existing sched_rt throttling mechanism. This patch does not address that. Signed-off-by: Paul Turner Reviewed-by: Hidetoshi Seto Signed-off-by: Peter Zijlstra Link: http://lkml.kernel.org/r/20110721184756.878333391@google.com Signed-off-by: Ingo Molnar --- kernel/sched_fair.c | 6 ++++++ 1 file changed, 6 insertions(+) (limited to 'kernel/sched_fair.c') diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index f4b732a3552b..f86b0cb5eb29 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -1310,16 +1310,19 @@ enqueue_task_fair(struct rq *rq, struct task_struct *p, int flags) break; cfs_rq = cfs_rq_of(se); enqueue_entity(cfs_rq, se, flags); + cfs_rq->h_nr_running++; flags = ENQUEUE_WAKEUP; } for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); + cfs_rq->h_nr_running++; update_cfs_load(cfs_rq, 0); update_cfs_shares(cfs_rq); } + inc_nr_running(rq); hrtick_update(rq); } @@ -1339,6 +1342,7 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); dequeue_entity(cfs_rq, se, flags); + cfs_rq->h_nr_running--; /* Don't dequeue parent if it has other entities besides us */ if (cfs_rq->load.weight) { @@ -1358,11 +1362,13 @@ static void dequeue_task_fair(struct rq *rq, struct task_struct *p, int flags) for_each_sched_entity(se) { cfs_rq = cfs_rq_of(se); + cfs_rq->h_nr_running--; update_cfs_load(cfs_rq, 0); update_cfs_shares(cfs_rq); } + dec_nr_running(rq); hrtick_update(rq); } -- cgit v1.2.3