| Subject: sched: Move task_struct cleanup to RCU |
| From: Thomas Gleixner <tglx@linutronix.de> |
| Date: Tue, 31 May 2011 16:59:16 +0200 |
| |
| __put_task_struct() does quite some expensive work. We don't want to |
| burden random tasks with that. |
| |
| Signed-off-by: Thomas Gleixner <tglx@linutronix.de> |
| --- |
| include/linux/sched.h | 13 +++++++++++++ |
| kernel/fork.c | 15 ++++++++++++++- |
| 2 files changed, 27 insertions(+), 1 deletion(-) |
| |
| --- a/include/linux/sched.h |
| +++ b/include/linux/sched.h |
| @@ -1936,6 +1936,9 @@ struct task_struct { |
| unsigned int sequential_io; |
| unsigned int sequential_io_avg; |
| #endif |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| + struct rcu_head put_rcu; |
| +#endif |
| #ifdef CONFIG_DEBUG_ATOMIC_SLEEP |
| unsigned long task_state_change; |
| #endif |
| @@ -2174,6 +2177,15 @@ extern struct pid *cad_pid; |
| extern void free_task(struct task_struct *tsk); |
| #define get_task_struct(tsk) do { atomic_inc(&(tsk)->usage); } while(0) |
| |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| +extern void __put_task_struct_cb(struct rcu_head *rhp); |
| + |
| +static inline void put_task_struct(struct task_struct *t) |
| +{ |
| + if (atomic_dec_and_test(&t->usage)) |
| + call_rcu(&t->put_rcu, __put_task_struct_cb); |
| +} |
| +#else |
| extern void __put_task_struct(struct task_struct *t); |
| |
| static inline void put_task_struct(struct task_struct *t) |
| @@ -2181,6 +2193,7 @@ static inline void put_task_struct(struc |
| if (atomic_dec_and_test(&t->usage)) |
| __put_task_struct(t); |
| } |
| +#endif |
| |
| struct task_struct *task_rcu_dereference(struct task_struct **ptask); |
| struct task_struct *try_get_task_struct(struct task_struct **ptask); |
| --- a/kernel/fork.c |
| +++ b/kernel/fork.c |
| @@ -251,7 +251,9 @@ static inline void put_signal_struct(str |
| if (atomic_dec_and_test(&sig->sigcnt)) |
| free_signal_struct(sig); |
| } |
| - |
| +#ifdef CONFIG_PREEMPT_RT_BASE |
| +static |
| +#endif |
| void __put_task_struct(struct task_struct *tsk) |
| { |
| WARN_ON(!tsk->exit_state); |
| @@ -268,7 +270,18 @@ void __put_task_struct(struct task_struc |
| if (!profile_handoff_task(tsk)) |
| free_task(tsk); |
| } |
| +#ifndef CONFIG_PREEMPT_RT_BASE |
| EXPORT_SYMBOL_GPL(__put_task_struct); |
| +#else |
| +void __put_task_struct_cb(struct rcu_head *rhp) |
| +{ |
| + struct task_struct *tsk = container_of(rhp, struct task_struct, put_rcu); |
| + |
| + __put_task_struct(tsk); |
| + |
| +} |
| +EXPORT_SYMBOL_GPL(__put_task_struct_cb); |
| +#endif |
| |
| void __init __weak arch_task_cache_init(void) { } |
| |