From 4553dab7f3e57b70fee61739325b6ff7bb56ac9b Mon Sep 17 00:00:00 2001 From: Peter Boonstoppel Date: Thu, 9 Aug 2012 15:34:47 -0700 Subject: sched: Unthrottle rt runqueues in __disable_runtime() commit a4c96ae319b8047f62dedbe1eac79e321c185749 upstream. migrate_tasks() uses _pick_next_task_rt() to get tasks from the real-time runqueues to be migrated. When rt_rq is throttled _pick_next_task_rt() won't return anything, in which case migrate_tasks() can't move all threads over and gets stuck in an infinite loop. Instead unthrottle rt runqueues before migrating tasks. Additionally: move unthrottle_offline_cfs_rqs() to rq_offline_fair() Signed-off-by: Peter Boonstoppel Signed-off-by: Peter Zijlstra Cc: Paul Turner Link: http://lkml.kernel.org/r/5FBF8E85CA34454794F0F7ECBA79798F379D3648B7@HQMAIL04.nvidia.com Signed-off-by: Ingo Molnar [ lizf: backported to 3.4: adjust context ] Signed-off-by: Li Zefan [bwh: Backported to 3.2: - Adjust filenames - unthrottle_offline_cfs_rqs() is already static, but defined in sched.c after including sched_fair.c, so add forward declaration - unthrottle_offline_cfs_rqs() also needs to be defined for all CONFIG_SMP configurations now] Signed-off-by: Ben Hutchings --- kernel/sched.c | 13 ++++++++----- kernel/sched_fair.c | 3 +++ kernel/sched_rt.c | 1 + 3 files changed, 12 insertions(+), 5 deletions(-) diff --git a/kernel/sched.c b/kernel/sched.c index d93369a977d1..ea85b0d2bbf2 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -2189,6 +2189,10 @@ static int irqtime_account_si_update(void) #endif +#ifdef CONFIG_SMP +static void unthrottle_offline_cfs_rqs(struct rq *rq); +#endif + #include "sched_idletask.c" #include "sched_fair.c" #include "sched_rt.c" @@ -6566,8 +6570,6 @@ static void unthrottle_offline_cfs_rqs(struct rq *rq) unthrottle_cfs_rq(cfs_rq); } } -#else -static void unthrottle_offline_cfs_rqs(struct rq *rq) {} #endif /* @@ -6595,9 +6597,6 @@ static void migrate_tasks(unsigned int dead_cpu) */ rq->stop = NULL; - /* Ensure any throttled groups are reachable by pick_next_task */ - unthrottle_offline_cfs_rqs(rq); - for ( ; ; ) { /* * There's this thread running, bail when that's the only @@ -6624,6 +6623,10 @@ static void migrate_tasks(unsigned int dead_cpu) #endif /* CONFIG_HOTPLUG_CPU */ +#if !defined(CONFIG_HOTPLUG_CPU) || !defined(CONFIG_CFS_BANDWIDTH) +static void unthrottle_offline_cfs_rqs(struct rq *rq) {} +#endif + #if defined(CONFIG_SCHED_DEBUG) && defined(CONFIG_SYSCTL) static struct ctl_table sd_ctl_dir[] = { diff --git a/kernel/sched_fair.c b/kernel/sched_fair.c index 5b9e456ea98c..37f3f3925d3d 100644 --- a/kernel/sched_fair.c +++ b/kernel/sched_fair.c @@ -4848,6 +4848,9 @@ static void rq_online_fair(struct rq *rq) static void rq_offline_fair(struct rq *rq) { update_sysctl(); + + /* Ensure any throttled groups are reachable by pick_next_task */ + unthrottle_offline_cfs_rqs(rq); } #else /* CONFIG_SMP */ diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index d0fff8139377..2992f93b68cb 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -509,6 +509,7 @@ balanced: * runtime - in which case borrowing doesn't make sense. */ rt_rq->rt_runtime = RUNTIME_INF; + rt_rq->rt_throttled = 0; raw_spin_unlock(&rt_rq->rt_runtime_lock); raw_spin_unlock(&rt_b->rt_runtime_lock); } -- cgit v1.2.3