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Merge branches 'bug.2018.11.12a', 'consolidate.2018.12.01a', 'doc.2018.11.12a', 'fixes.2018.11.12a', 'initrd.2018.11.08b', 'sil.2018.11.12a' and 'srcu.2018.11.27a' into HEAD

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bug.2018.11.12a:  Get rid of BUG_ON() and friends
consolidate.2018.12.01a:  Continued RCU flavor-consolidation cleanup
doc.2018.11.12a:  Documentation updates
fixes.2018.11.12a:  Miscellaneous fixes
initrd.2018.11.08b:  Automate creation of rcutorture initrd
sil.2018.11.12a:  Remove more spin_unlock_wait() calls
This commit is contained in:
Paul E. McKenney
2018-12-01 12:43:16 -08:00
parent f0ad56e876 df56e0f960 97b59370fa 3d709ab5a1 b94ec36896 d4d592a6ee aacb5d91ab
commit eaaf055f27
85 changed files with 3887 additions and 3925 deletions
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37
kernel/rcu/tree_plugin.h
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@@ -397,6 +397,11 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp)
return rnp->gp_tasks != NULL;
}
/* Bias and limit values for ->rcu_read_lock_nesting. */
#define RCU_NEST_BIAS INT_MAX
#define RCU_NEST_NMAX (-INT_MAX / 2)
#define RCU_NEST_PMAX (INT_MAX / 2)
/*
* Preemptible RCU implementation for rcu_read_lock().
* Just increment ->rcu_read_lock_nesting, shared state will be updated
@@ -405,6 +410,8 @@ static int rcu_preempt_blocked_readers_cgp(struct rcu_node *rnp)
void __rcu_read_lock(void)
{
current->rcu_read_lock_nesting++;
if (IS_ENABLED(CONFIG_PROVE_LOCKING))
WARN_ON_ONCE(current->rcu_read_lock_nesting > RCU_NEST_PMAX);
barrier(); /* critical section after entry code. */
}
EXPORT_SYMBOL_GPL(__rcu_read_lock);
@@ -424,20 +431,18 @@ void __rcu_read_unlock(void)
--t->rcu_read_lock_nesting;
} else {
barrier(); /* critical section before exit code. */
t->rcu_read_lock_nesting = INT_MIN;
t->rcu_read_lock_nesting = -RCU_NEST_BIAS;
barrier(); /* assign before ->rcu_read_unlock_special load */
if (unlikely(READ_ONCE(t->rcu_read_unlock_special.s)))
rcu_read_unlock_special(t);
barrier(); /* ->rcu_read_unlock_special load before assign */
t->rcu_read_lock_nesting = 0;
}
#ifdef CONFIG_PROVE_LOCKING
{
int rrln = READ_ONCE(t->rcu_read_lock_nesting);
if (IS_ENABLED(CONFIG_PROVE_LOCKING)) {
int rrln = t->rcu_read_lock_nesting;
WARN_ON_ONCE(rrln < 0 && rrln > INT_MIN / 2);
WARN_ON_ONCE(rrln < 0 && rrln > RCU_NEST_NMAX);
}
#endif /* #ifdef CONFIG_PROVE_LOCKING */
}
EXPORT_SYMBOL_GPL(__rcu_read_unlock);
@@ -597,7 +602,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
*/
static bool rcu_preempt_need_deferred_qs(struct task_struct *t)
{
return (this_cpu_ptr(&rcu_data)->deferred_qs ||
return (__this_cpu_read(rcu_data.deferred_qs) ||
READ_ONCE(t->rcu_read_unlock_special.s)) &&
t->rcu_read_lock_nesting <= 0;
}
@@ -617,11 +622,11 @@ static void rcu_preempt_deferred_qs(struct task_struct *t)
if (!rcu_preempt_need_deferred_qs(t))
return;
if (couldrecurse)
t->rcu_read_lock_nesting -= INT_MIN;
t->rcu_read_lock_nesting -= RCU_NEST_BIAS;
local_irq_save(flags);
rcu_preempt_deferred_qs_irqrestore(t, flags);
if (couldrecurse)
t->rcu_read_lock_nesting += INT_MIN;
t->rcu_read_lock_nesting += RCU_NEST_BIAS;
}
/*
@@ -642,13 +647,21 @@ static void rcu_read_unlock_special(struct task_struct *t)
local_irq_save(flags);
irqs_were_disabled = irqs_disabled_flags(flags);
if ((preempt_bh_were_disabled || irqs_were_disabled) &&
t->rcu_read_unlock_special.b.blocked) {
if (preempt_bh_were_disabled || irqs_were_disabled) {
WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, false);
/* Need to defer quiescent state until everything is enabled. */
raise_softirq_irqoff(RCU_SOFTIRQ);
if (irqs_were_disabled) {
/* Enabling irqs does not reschedule, so... */
raise_softirq_irqoff(RCU_SOFTIRQ);
} else {
/* Enabling BH or preempt does reschedule, so... */
set_tsk_need_resched(current);
set_preempt_need_resched();
}
local_irq_restore(flags);
return;
}
WRITE_ONCE(t->rcu_read_unlock_special.b.exp_hint, false);
rcu_preempt_deferred_qs_irqrestore(t, flags);
}