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| author | Peter Zijlstra <peterz@infradead.org> | 2009-04-01 18:40:15 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2009-07-10 10:43:29 +0200 |
| commit | a1ba4d8ba9f06a397e97cbd67a93ee306860b40a (patch) | |
| tree | f0e0f92a2c0763f8ec162c2b0e2abc389075b207 | |
| parent | d4ec36bac3de39b7e10ec8f42fbdd20d9a9ed753 (diff) | |
| download | lwn-a1ba4d8ba9f06a397e97cbd67a93ee306860b40a.tar.gz lwn-a1ba4d8ba9f06a397e97cbd67a93ee306860b40a.zip | |
sched_rt: Fix overload bug on rt group scheduling
Fixes an easily triggerable BUG() when setting process affinities.
Make sure to count the number of migratable tasks in the same place:
the root rt_rq. Otherwise the number doesn't make sense and we'll hit
the BUG in set_cpus_allowed_rt().
Also, make sure we only count tasks, not groups (this is probably
already taken care of by the fact that rt_se->nr_cpus_allowed will be 0
for groups, but be more explicit)
Tested-by: Thomas Gleixner <tglx@linutronix.de>
CC: stable@kernel.org
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Gregory Haskins <ghaskins@novell.com>
LKML-Reference: <1247067476.9777.57.camel@twins>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | kernel/sched.c | 1 | ||||
| -rw-r--r-- | kernel/sched_rt.c | 18 |
2 files changed, 18 insertions, 1 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 7c9098d186e6..a17f3d9a8bfa 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -493,6 +493,7 @@ struct rt_rq { #endif #ifdef CONFIG_SMP unsigned long rt_nr_migratory; + unsigned long rt_nr_total; int overloaded; struct plist_head pushable_tasks; #endif diff --git a/kernel/sched_rt.c b/kernel/sched_rt.c index 9bf0d2a73045..3918e01994e0 100644 --- a/kernel/sched_rt.c +++ b/kernel/sched_rt.c @@ -10,6 +10,8 @@ static inline struct task_struct *rt_task_of(struct sched_rt_entity *rt_se) #ifdef CONFIG_RT_GROUP_SCHED +#define rt_entity_is_task(rt_se) (!(rt_se)->my_q) + static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) { return rt_rq->rq; @@ -22,6 +24,8 @@ static inline struct rt_rq *rt_rq_of_se(struct sched_rt_entity *rt_se) #else /* CONFIG_RT_GROUP_SCHED */ +#define rt_entity_is_task(rt_se) (1) + static inline struct rq *rq_of_rt_rq(struct rt_rq *rt_rq) { return container_of(rt_rq, struct rq, rt); @@ -73,7 +77,7 @@ static inline void rt_clear_overload(struct rq *rq) static void update_rt_migration(struct rt_rq *rt_rq) { - if (rt_rq->rt_nr_migratory && (rt_rq->rt_nr_running > 1)) { + if (rt_rq->rt_nr_migratory && rt_rq->rt_nr_total > 1) { if (!rt_rq->overloaded) { rt_set_overload(rq_of_rt_rq(rt_rq)); rt_rq->overloaded = 1; @@ -86,6 +90,12 @@ static void update_rt_migration(struct rt_rq *rt_rq) static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + if (!rt_entity_is_task(rt_se)) + return; + + rt_rq = &rq_of_rt_rq(rt_rq)->rt; + + rt_rq->rt_nr_total++; if (rt_se->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory++; @@ -94,6 +104,12 @@ static void inc_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) static void dec_rt_migration(struct sched_rt_entity *rt_se, struct rt_rq *rt_rq) { + if (!rt_entity_is_task(rt_se)) + return; + + rt_rq = &rq_of_rt_rq(rt_rq)->rt; + + rt_rq->rt_nr_total--; if (rt_se->nr_cpus_allowed > 1) rt_rq->rt_nr_migratory--; |