diff options
author | Peter Zijlstra <a.p.zijlstra@chello.nl> | 2008-02-13 17:45:39 +0300 |
---|---|---|
committer | Ingo Molnar <mingo@elte.hu> | 2008-02-13 17:45:39 +0300 |
commit | 8ed3699682be75fd68281239c202ad3830f9c72d (patch) | |
tree | 5af86fb155e475e906e14dc6aa5aa5a890cca7a2 /kernel | |
parent | 720a2592cf1b9af86f30c44e8d89348826c03372 (diff) | |
download | linux-8ed3699682be75fd68281239c202ad3830f9c72d.tar.xz |
sched: fair-group: separate tg->shares from task_group_lock
On Mon, 2008-02-11 at 15:09 +0300, Denis V. Lunev wrote:
> BUG: sleeping function called from invalid context
> at /home/den/src/linux-netns26/kernel/mutex.c:209
> in_atomic():1, irqs_disabled():0
> no locks held by swapper/0.
> Pid: 0, comm: swapper Not tainted 2.6.24 #304
>
> Call Trace:
> <IRQ> [<ffffffff80252d1e>] ? __debug_show_held_locks+0x15/0x27
> [<ffffffff8022c2a8>] __might_sleep+0xc0/0xdf
> [<ffffffff8049f1df>] mutex_lock_nested+0x28/0x2a9
> [<ffffffff80231294>] sched_destroy_group+0x18/0xea
> [<ffffffff8023e835>] sched_destroy_user+0xd/0xf
> [<ffffffff8023e8c1>] free_uid+0x8a/0xab
> [<ffffffff80233e24>] __put_task_struct+0x3f/0xd3
> [<ffffffff80236708>] delayed_put_task_struct+0x23/0x25
> [<ffffffff8026fda7>] __rcu_process_callbacks+0x8d/0x215
> [<ffffffff8026ff52>] rcu_process_callbacks+0x23/0x44
> [<ffffffff8023a2ae>] __do_softirq+0x79/0xf8
> [<ffffffff8020f8c3>] ? profile_pc+0x2a/0x67
> [<ffffffff8020d38c>] call_softirq+0x1c/0x30
> [<ffffffff8020f689>] do_softirq+0x61/0x9c
> [<ffffffff8023a233>] irq_exit+0x51/0x53
> [<ffffffff8021bd1a>] smp_apic_timer_interrupt+0x77/0xad
> [<ffffffff8020ce3b>] apic_timer_interrupt+0x6b/0x70
> <EOI> [<ffffffff8020b0dd>] ? default_idle+0x43/0x76
> [<ffffffff8020b0db>] ? default_idle+0x41/0x76
> [<ffffffff8020b09a>] ? default_idle+0x0/0x76
> [<ffffffff8020b186>] ? cpu_idle+0x76/0x98
separate the tg->shares protection from the task_group lock.
Reported-by: Denis V. Lunev <den@openvz.org>
Tested-by: Denis V. Lunev <den@openvz.org>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Diffstat (limited to 'kernel')
-rw-r--r-- | kernel/sched.c | 37 |
1 files changed, 17 insertions, 20 deletions
diff --git a/kernel/sched.c b/kernel/sched.c index 3eedd5260907..6b02276baaa6 100644 --- a/kernel/sched.c +++ b/kernel/sched.c @@ -232,10 +232,10 @@ static struct cfs_rq *init_cfs_rq_p[NR_CPUS]; static struct sched_rt_entity *init_sched_rt_entity_p[NR_CPUS]; static struct rt_rq *init_rt_rq_p[NR_CPUS]; -/* task_group_mutex serializes add/remove of task groups and also changes to +/* task_group_lock serializes add/remove of task groups and also changes to * a task group's cpu shares. */ -static DEFINE_MUTEX(task_group_mutex); +static DEFINE_SPINLOCK(task_group_lock); /* doms_cur_mutex serializes access to doms_cur[] array */ static DEFINE_MUTEX(doms_cur_mutex); @@ -295,16 +295,6 @@ static inline void set_task_rq(struct task_struct *p, unsigned int cpu) p->rt.parent = task_group(p)->rt_se[cpu]; } -static inline void lock_task_group_list(void) -{ - mutex_lock(&task_group_mutex); -} - -static inline void unlock_task_group_list(void) -{ - mutex_unlock(&task_group_mutex); -} - static inline void lock_doms_cur(void) { mutex_lock(&doms_cur_mutex); @@ -318,8 +308,6 @@ static inline void unlock_doms_cur(void) #else static inline void set_task_rq(struct task_struct *p, unsigned int cpu) { } -static inline void lock_task_group_list(void) { } -static inline void unlock_task_group_list(void) { } static inline void lock_doms_cur(void) { } static inline void unlock_doms_cur(void) { } @@ -7571,6 +7559,7 @@ struct task_group *sched_create_group(void) struct rt_rq *rt_rq; struct sched_rt_entity *rt_se; struct rq *rq; + unsigned long flags; int i; tg = kzalloc(sizeof(*tg), GFP_KERNEL); @@ -7620,7 +7609,7 @@ struct task_group *sched_create_group(void) init_tg_rt_entry(rq, tg, rt_rq, rt_se, i, 0); } - lock_task_group_list(); + spin_lock_irqsave(&task_group_lock, flags); for_each_possible_cpu(i) { rq = cpu_rq(i); cfs_rq = tg->cfs_rq[i]; @@ -7629,7 +7618,7 @@ struct task_group *sched_create_group(void) list_add_rcu(&rt_rq->leaf_rt_rq_list, &rq->leaf_rt_rq_list); } list_add_rcu(&tg->list, &task_groups); - unlock_task_group_list(); + spin_unlock_irqrestore(&task_group_lock, flags); return tg; @@ -7650,9 +7639,10 @@ void sched_destroy_group(struct task_group *tg) { struct cfs_rq *cfs_rq = NULL; struct rt_rq *rt_rq = NULL; + unsigned long flags; int i; - lock_task_group_list(); + spin_lock_irqsave(&task_group_lock, flags); for_each_possible_cpu(i) { cfs_rq = tg->cfs_rq[i]; list_del_rcu(&cfs_rq->leaf_cfs_rq_list); @@ -7660,7 +7650,7 @@ void sched_destroy_group(struct task_group *tg) list_del_rcu(&rt_rq->leaf_rt_rq_list); } list_del_rcu(&tg->list); - unlock_task_group_list(); + spin_unlock_irqrestore(&task_group_lock, flags); BUG_ON(!cfs_rq); @@ -7728,13 +7718,16 @@ static void set_se_shares(struct sched_entity *se, unsigned long shares) } } +static DEFINE_MUTEX(shares_mutex); + int sched_group_set_shares(struct task_group *tg, unsigned long shares) { int i; struct cfs_rq *cfs_rq; struct rq *rq; + unsigned long flags; - lock_task_group_list(); + mutex_lock(&shares_mutex); if (tg->shares == shares) goto done; @@ -7746,10 +7739,12 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) * load_balance_fair) from referring to this group first, * by taking it off the rq->leaf_cfs_rq_list on each cpu. */ + spin_lock_irqsave(&task_group_lock, flags); for_each_possible_cpu(i) { cfs_rq = tg->cfs_rq[i]; list_del_rcu(&cfs_rq->leaf_cfs_rq_list); } + spin_unlock_irqrestore(&task_group_lock, flags); /* wait for any ongoing reference to this group to finish */ synchronize_sched(); @@ -7769,13 +7764,15 @@ int sched_group_set_shares(struct task_group *tg, unsigned long shares) * Enable load balance activity on this group, by inserting it back on * each cpu's rq->leaf_cfs_rq_list. */ + spin_lock_irqsave(&task_group_lock, flags); for_each_possible_cpu(i) { rq = cpu_rq(i); cfs_rq = tg->cfs_rq[i]; list_add_rcu(&cfs_rq->leaf_cfs_rq_list, &rq->leaf_cfs_rq_list); } + spin_unlock_irqrestore(&task_group_lock, flags); done: - unlock_task_group_list(); + mutex_unlock(&shares_mutex); return 0; } |