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author | Ingo Molnar <mingo@elte.hu> | 2011-07-01 10:34:09 +0200 |
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committer | Ingo Molnar <mingo@elte.hu> | 2011-07-01 10:34:24 +0200 |
commit | 36b2e922b5acd291051fab25bc7535274ce49532 (patch) | |
tree | ef4cdd6894075bb419cc31625b037f2b9212962f /kernel/sched.c | |
parent | e197f094b7da7d94812492cfcd706d143f1020e5 (diff) | |
parent | b0af8dfdd67699e25083478c63eedef2e72ebd85 (diff) | |
download | op-kernel-dev-36b2e922b5acd291051fab25bc7535274ce49532.zip op-kernel-dev-36b2e922b5acd291051fab25bc7535274ce49532.tar.gz |
Merge commit 'v3.0-rc5' into sched/core
Merge reason: Move to a (much) newer base.
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel/sched.c')
-rw-r--r-- | kernel/sched.c | 21 |
1 files changed, 16 insertions, 5 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index fd18f39..5925275 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -605,10 +605,10 @@ static inline int cpu_of(struct rq *rq) /* * Return the group to which this tasks belongs. * - * We use task_subsys_state_check() and extend the RCU verification - * with lockdep_is_held(&p->pi_lock) because cpu_cgroup_attach() - * holds that lock for each task it moves into the cgroup. Therefore - * by holding that lock, we pin the task to the current cgroup. + * We use task_subsys_state_check() and extend the RCU verification with + * pi->lock and rq->lock because cpu_cgroup_attach() holds those locks for each + * task it moves into the cgroup. Therefore by holding either of those locks, + * we pin the task to the current cgroup. */ static inline struct task_group *task_group(struct task_struct *p) { @@ -616,7 +616,8 @@ static inline struct task_group *task_group(struct task_struct *p) struct cgroup_subsys_state *css; css = task_subsys_state_check(p, cpu_cgroup_subsys_id, - lockdep_is_held(&p->pi_lock)); + lockdep_is_held(&p->pi_lock) || + lockdep_is_held(&task_rq(p)->lock)); tg = container_of(css, struct task_group, css); return autogroup_task_group(p, tg); @@ -2200,6 +2201,16 @@ void set_task_cpu(struct task_struct *p, unsigned int new_cpu) !(task_thread_info(p)->preempt_count & PREEMPT_ACTIVE)); #ifdef CONFIG_LOCKDEP + /* + * The caller should hold either p->pi_lock or rq->lock, when changing + * a task's CPU. ->pi_lock for waking tasks, rq->lock for runnable tasks. + * + * sched_move_task() holds both and thus holding either pins the cgroup, + * see set_task_rq(). + * + * Furthermore, all task_rq users should acquire both locks, see + * task_rq_lock(). + */ WARN_ON_ONCE(debug_locks && !(lockdep_is_held(&p->pi_lock) || lockdep_is_held(&task_rq(p)->lock))); #endif |