From 1467faf21897d6b1587ee70f781ca0b64a245f6a Mon Sep 17 00:00:00 2001 From: Thomas Gleixner Date: Tue, 31 May 2011 16:59:16 +0200 Subject: [PATCH 129/352] sched: Move task_struct cleanup to RCU __put_task_struct() does quite some expensive work. We don't want to burden random tasks with that. Signed-off-by: Thomas Gleixner --- include/linux/sched.h | 13 +++++++++++++ kernel/fork.c | 15 ++++++++++++++- 2 files changed, 27 insertions(+), 1 deletion(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index d57d9ef..3ca69a0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2142,6 +2142,9 @@ 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 @@ -2403,6 +2406,15 @@ 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) @@ -2410,6 +2422,7 @@ static inline void put_task_struct(struct task_struct *t) 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); diff --git a/kernel/fork.c b/kernel/fork.c index 206afae..2a04c19 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -386,7 +386,9 @@ static inline void put_signal_struct(struct signal_struct *sig) 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); @@ -403,7 +405,18 @@ void __put_task_struct(struct task_struct *tsk) 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) { } -- 2.7.4