commit 51e718d5c5934f469b81adf97b15639beb168c7f
author Peter Boonstoppel <pboonstoppel@nvidia.com> Thu Aug 09 15:34:47 2012 -0700
committer Gerrit - the friendly Code Review server <code-review@localhost> Wed Aug 21 11:36:14 2013 -0700
tree f826adb26fa7748209aaf49e27c7c3417969b543
parent a3733c170509e6729d92414feb732ffdf57ee143

sched: Unthrottle rt runqueues in __disable_runtime()

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()

Change-Id: If8a4a399f1a14b7f4789c1b205dcfadbde555214
Signed-off-by: Peter Boonstoppel <pboonstoppel@nvidia.com>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Turner <pjt@google.com>
Link: http://lkml.kernel.org/r/5FBF8E85CA34454794F0F7ECBA79798F379D3648B7@HQMAIL04.nvidia.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Git-commit: a4c96ae319b8047f62dedbe1eac79e321c185749
Git-repo: git://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Signed-off-by: Syed Rameez Mustafa <rameezmustafa@codeaurora.org>

kernel/sched/core.c

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index d9c4b64..5256d44 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5202,9 +5202,6 @@
 	 */
 	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

kernel/sched/fair.c

diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 5d6ab86..2e98983 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2060,7 +2060,7 @@
 	hrtimer_cancel(&cfs_b->slack_timer);
 }
 
-void unthrottle_offline_cfs_rqs(struct rq *rq)
+static void unthrottle_offline_cfs_rqs(struct rq *rq)
 {
 	struct cfs_rq *cfs_rq;
 
@@ -2114,7 +2114,7 @@
 	return NULL;
 }
 static inline void destroy_cfs_bandwidth(struct cfs_bandwidth *cfs_b) {}
-void unthrottle_offline_cfs_rqs(struct rq *rq) {}
+static inline void unthrottle_offline_cfs_rqs(struct rq *rq) {}
 
 #endif /* CONFIG_CFS_BANDWIDTH */
 
@@ -5186,6 +5186,9 @@
 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);
 }
 
 #endif /* CONFIG_SMP */

kernel/sched/rt.c

diff --git a/kernel/sched/rt.c b/kernel/sched/rt.c
index 8f32475..be427c5 100644
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -685,6 +685,7 @@
 		 * 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);
 	}

kernel/sched/sched.h

diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h
index 5370bcb..55f6d9c 100644
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1155,7 +1155,6 @@
 
 extern void init_cfs_rq(struct cfs_rq *cfs_rq);
 extern void init_rt_rq(struct rt_rq *rt_rq, struct rq *rq);
-extern void unthrottle_offline_cfs_rqs(struct rq *rq);
 
 extern void account_cfs_bandwidth_used(int enabled, int was_enabled);