This is a note to let you know that I've just added the patch titled
sched: Unthrottle rt runqueues in __disable_runtime()
to the 3.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
sched-unthrottle-rt-runqueues-in-__disable_runtime.patch
and it can be found in the queue-3.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From a4c96ae319b8047f62dedbe1eac79e321c185749 Mon Sep 17 00:00:00 2001
From: Peter Boonstoppel <pboonstoppel@xxxxxxxxxx>
Date: Thu, 9 Aug 2012 15:34:47 -0700
Subject: sched: Unthrottle rt runqueues in __disable_runtime()
From: Peter Boonstoppel <pboonstoppel@xxxxxxxxxx>
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 <pboonstoppel@xxxxxxxxxx>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@xxxxxxxxx>
Cc: Paul Turner <pjt@xxxxxxxxxx>
Link: http://lkml.kernel.org/r/5FBF8E85CA34454794F0F7ECBA79798F379D3648B7@xxxxxxxxxxxxxxxxxxx
Signed-off-by: Ingo Molnar <mingo@xxxxxxxxxx>
[ lizf: backported to 3.4: adjust context ]
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
kernel/sched/core.c | 3 ---
kernel/sched/fair.c | 7 +++++--
kernel/sched/rt.c | 1 +
kernel/sched/sched.h | 1 -
4 files changed, 6 insertions(+), 6 deletions(-)
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -5301,9 +5301,6 @@ static void migrate_tasks(unsigned int d
*/
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
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2071,7 +2071,7 @@ static void destroy_cfs_bandwidth(struct
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;
@@ -2125,7 +2125,7 @@ static inline struct cfs_bandwidth *tg_c
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 */
@@ -5171,6 +5171,9 @@ 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);
}
#endif /* CONFIG_SMP */
--- a/kernel/sched/rt.c
+++ b/kernel/sched/rt.c
@@ -685,6 +685,7 @@ 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);
}
--- a/kernel/sched/sched.h
+++ b/kernel/sched/sched.h
@@ -1138,7 +1138,6 @@ extern void print_rt_stats(struct seq_fi
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 cfs_bandwidth_usage_inc(void);
extern void cfs_bandwidth_usage_dec(void);
Patches currently in stable-queue which might be from pboonstoppel@xxxxxxxxxx are
queue-3.4/sched-unthrottle-rt-runqueues-in-__disable_runtime.patch
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