diff options
| -rw-r--r-- | include/linux/init_task.h | 9 | ||||
| -rw-r--r-- | include/linux/sched.h | 6 | ||||
| -rw-r--r-- | kernel/rcu/tree.h | 3 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 25 |
4 files changed, 15 insertions, 28 deletions
diff --git a/include/linux/init_task.h b/include/linux/init_task.h index 6df7f9fe0d01..2bb4c4f3531a 100644 --- a/include/linux/init_task.h +++ b/include/linux/init_task.h @@ -102,12 +102,6 @@ extern struct group_info init_groups; #define INIT_IDS #endif -#ifdef CONFIG_RCU_BOOST -#define INIT_TASK_RCU_BOOST() \ - .rcu_boost_mutex = NULL, -#else -#define INIT_TASK_RCU_BOOST() -#endif #ifdef CONFIG_TREE_PREEMPT_RCU #define INIT_TASK_RCU_TREE_PREEMPT() \ .rcu_blocked_node = NULL, @@ -119,8 +113,7 @@ extern struct group_info init_groups; .rcu_read_lock_nesting = 0, \ .rcu_read_unlock_special = 0, \ .rcu_node_entry = LIST_HEAD_INIT(tsk.rcu_node_entry), \ - INIT_TASK_RCU_TREE_PREEMPT() \ - INIT_TASK_RCU_BOOST() + INIT_TASK_RCU_TREE_PREEMPT() #else #define INIT_TASK_RCU_PREEMPT(tsk) #endif diff --git a/include/linux/sched.h b/include/linux/sched.h index 306f4f0c987a..3cfbc05e66e6 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1270,9 +1270,6 @@ struct task_struct { #ifdef CONFIG_TREE_PREEMPT_RCU struct rcu_node *rcu_blocked_node; #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -#ifdef CONFIG_RCU_BOOST - struct rt_mutex *rcu_boost_mutex; -#endif /* #ifdef CONFIG_RCU_BOOST */ #if defined(CONFIG_SCHEDSTATS) || defined(CONFIG_TASK_DELAY_ACCT) struct sched_info sched_info; @@ -2009,9 +2006,6 @@ static inline void rcu_copy_process(struct task_struct *p) #ifdef CONFIG_TREE_PREEMPT_RCU p->rcu_blocked_node = NULL; #endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */ -#ifdef CONFIG_RCU_BOOST - p->rcu_boost_mutex = NULL; -#endif /* #ifdef CONFIG_RCU_BOOST */ INIT_LIST_HEAD(&p->rcu_node_entry); } diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 3eeb919e26a2..60fb0eaa2d16 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -177,6 +177,9 @@ struct rcu_node { /* to carry out the boosting is fully */ /* released with no future boostee accesses */ /* before that rt_mutex is re-initialized. */ + struct rt_mutex boost_mtx; + /* Used only for the priority-boosting */ + /* side effect, not as a lock. */ unsigned long boost_time; /* When to start boosting (jiffies). */ struct task_struct *boost_kthread_task; diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 9c811879d31e..719587af7b10 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -33,6 +33,7 @@ #define RCU_KTHREAD_PRIO 1 #ifdef CONFIG_RCU_BOOST +#include "../locking/rtmutex_common.h" #define RCU_BOOST_PRIO CONFIG_RCU_BOOST_PRIO #else #define RCU_BOOST_PRIO RCU_KTHREAD_PRIO @@ -336,7 +337,7 @@ void rcu_read_unlock_special(struct task_struct *t) unsigned long flags; struct list_head *np; #ifdef CONFIG_RCU_BOOST - struct rt_mutex *rbmp = NULL; + bool drop_boost_mutex = false; #endif /* #ifdef CONFIG_RCU_BOOST */ struct rcu_node *rnp; int special; @@ -398,11 +399,8 @@ void rcu_read_unlock_special(struct task_struct *t) #ifdef CONFIG_RCU_BOOST if (&t->rcu_node_entry == rnp->boost_tasks) rnp->boost_tasks = np; - /* Snapshot/clear ->rcu_boost_mutex with rcu_node lock held. */ - if (t->rcu_boost_mutex) { - rbmp = t->rcu_boost_mutex; - t->rcu_boost_mutex = NULL; - } + /* Snapshot ->boost_mtx ownership with rcu_node lock held. */ + drop_boost_mutex = rt_mutex_owner(&rnp->boost_mtx) == t; #endif /* #ifdef CONFIG_RCU_BOOST */ /* @@ -427,8 +425,8 @@ void rcu_read_unlock_special(struct task_struct *t) #ifdef CONFIG_RCU_BOOST /* Unboost if we were boosted. */ - if (rbmp) { - rt_mutex_unlock(rbmp); + if (drop_boost_mutex) { + rt_mutex_unlock(&rnp->boost_mtx); complete(&rnp->boost_completion); } #endif /* #ifdef CONFIG_RCU_BOOST */ @@ -1151,7 +1149,6 @@ static void rcu_wake_cond(struct task_struct *t, int status) static int rcu_boost(struct rcu_node *rnp) { unsigned long flags; - struct rt_mutex mtx; struct task_struct *t; struct list_head *tb; @@ -1202,14 +1199,14 @@ static int rcu_boost(struct rcu_node *rnp) * section. */ t = container_of(tb, struct task_struct, rcu_node_entry); - rt_mutex_init_proxy_locked(&mtx, t); - t->rcu_boost_mutex = &mtx; + rt_mutex_init_proxy_locked(&rnp->boost_mtx, t); init_completion(&rnp->boost_completion); raw_spin_unlock_irqrestore(&rnp->lock, flags); - rt_mutex_lock(&mtx); /* Side effect: boosts task t's priority. */ - rt_mutex_unlock(&mtx); /* Keep lockdep happy. */ + /* Lock only for side effect: boosts task t's priority. */ + rt_mutex_lock(&rnp->boost_mtx); + rt_mutex_unlock(&rnp->boost_mtx); /* Then keep lockdep happy. */ - /* Wait until boostee is done accessing mtx before reinitializing. */ + /* Wait for boostee to be done w/boost_mtx before reinitializing. */ wait_for_completion(&rnp->boost_completion); return ACCESS_ONCE(rnp->exp_tasks) != NULL || |