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| author | Peter Zijlstra <peterz@infradead.org> | 2015-10-08 12:24:23 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-11-23 10:37:35 -0800 |
| commit | 2a67e741bbbc022e0fadf8c6dbc3a76019ecd0cf (patch) | |
| tree | 2f06a10ebf9f27272f6de99b0da5c19c5bdde6f6 /kernel/rcu/tree_plugin.h | |
| parent | 1ec218373b8ebda821aec00bb156a9c94fad9cd4 (diff) | |
| download | linux-stable-2a67e741bbbc022e0fadf8c6dbc3a76019ecd0cf.tar.gz linux-stable-2a67e741bbbc022e0fadf8c6dbc3a76019ecd0cf.tar.bz2 linux-stable-2a67e741bbbc022e0fadf8c6dbc3a76019ecd0cf.zip | |
rcu: Create transitive rnp->lock acquisition functions
Providing RCU's memory-ordering guarantees requires that the rcu_node
tree's locking provide transitive memory ordering, which the Linux kernel's
spinlocks currently do not provide unless smp_mb__after_unlock_lock()
is used. Having a separate smp_mb__after_unlock_lock() after each and
every lock acquisition is error-prone, hard to read, and a bit annoying,
so this commit provides wrapper functions that pull in the
smp_mb__after_unlock_lock() invocations.
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree_plugin.h')
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 18 |
1 files changed, 6 insertions, 12 deletions
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 630c19772630..fa0e3b96a9ed 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -301,8 +301,7 @@ static void rcu_preempt_note_context_switch(void) /* Possibly blocking in an RCU read-side critical section. */ rdp = this_cpu_ptr(rcu_state_p->rda); rnp = rdp->mynode; - raw_spin_lock_irqsave(&rnp->lock, flags); - smp_mb__after_unlock_lock(); + raw_spin_lock_irqsave_rcu_node(rnp, flags); t->rcu_read_unlock_special.b.blocked = true; t->rcu_blocked_node = rnp; @@ -457,8 +456,7 @@ void rcu_read_unlock_special(struct task_struct *t) */ for (;;) { rnp = t->rcu_blocked_node; - raw_spin_lock(&rnp->lock); /* irqs already disabled. */ - smp_mb__after_unlock_lock(); + raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ if (rnp == t->rcu_blocked_node) break; WARN_ON_ONCE(1); @@ -989,8 +987,7 @@ static int rcu_boost(struct rcu_node *rnp) READ_ONCE(rnp->boost_tasks) == NULL) return 0; /* Nothing left to boost. */ - raw_spin_lock_irqsave(&rnp->lock, flags); - smp_mb__after_unlock_lock(); + raw_spin_lock_irqsave_rcu_node(rnp, flags); /* * Recheck under the lock: all tasks in need of boosting @@ -1176,8 +1173,7 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp, "rcub/%d", rnp_index); if (IS_ERR(t)) return PTR_ERR(t); - raw_spin_lock_irqsave(&rnp->lock, flags); - smp_mb__after_unlock_lock(); + raw_spin_lock_irqsave_rcu_node(rnp, flags); rnp->boost_kthread_task = t; raw_spin_unlock_irqrestore(&rnp->lock, flags); sp.sched_priority = kthread_prio; @@ -1567,8 +1563,7 @@ static void rcu_prepare_for_idle(void) if (!*rdp->nxttail[RCU_DONE_TAIL]) continue; rnp = rdp->mynode; - raw_spin_lock(&rnp->lock); /* irqs already disabled. */ - smp_mb__after_unlock_lock(); + raw_spin_lock_rcu_node(rnp); /* irqs already disabled. */ needwake = rcu_accelerate_cbs(rsp, rnp, rdp); raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ if (needwake) @@ -2068,8 +2063,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp) bool needwake; struct rcu_node *rnp = rdp->mynode; - raw_spin_lock_irqsave(&rnp->lock, flags); - smp_mb__after_unlock_lock(); + raw_spin_lock_irqsave_rcu_node(rnp, flags); needwake = rcu_start_future_gp(rnp, rdp, &c); raw_spin_unlock_irqrestore(&rnp->lock, flags); if (needwake) |