From 3370c869acd8725ed7ff841e822277d85c74f3fb Mon Sep 17 00:00:00 2001 Message-Id: <3370c869acd8725ed7ff841e822277d85c74f3fb.1601675152.git.zanussi@kernel.org> In-Reply-To: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org> References: <5b5a156f9808b1acf1205606e03da117214549ea.1601675151.git.zanussi@kernel.org> From: Thomas Gleixner Date: Tue, 31 May 2011 16:59:16 +0200 Subject: [PATCH 105/333] sched: Move task_struct cleanup to RCU Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/4.19/older/patches-4.19.148-rt64.tar.xz __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 | 3 +++ include/linux/sched/task.h | 11 ++++++++++- kernel/fork.c | 15 ++++++++++++++- 3 files changed, 27 insertions(+), 2 deletions(-) diff --git a/include/linux/sched.h b/include/linux/sched.h index b6fbc5aa3d5d..9a0e01e48602 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1194,6 +1194,9 @@ 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 diff --git a/include/linux/sched/task.h b/include/linux/sched/task.h index 44c6f15800ff..d2b33e57c636 100644 --- a/include/linux/sched/task.h +++ b/include/linux/sched/task.h @@ -90,6 +90,15 @@ extern void sched_exec(void); #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) @@ -97,7 +106,7 @@ 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); #ifdef CONFIG_ARCH_WANTS_DYNAMIC_TASK_STRUCT diff --git a/kernel/fork.c b/kernel/fork.c index ccfcd44a370f..309f4a20d4ac 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -676,7 +676,9 @@ 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); @@ -693,7 +695,18 @@ 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) { } -- 2.17.1