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Merge branch 'idle.2013.09.25a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into HEAD

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Need to use Paul McKenney's "rcu_is_watching()" changes to fix
a perf/ftrace bug.
This commit is contained in:
Steven Rostedt (Red Hat) 2013-11-05 16:03:17 -05:00 committed by Steven Rostedt
commit 44847da1b9
9 changed files with 72 additions and 36 deletions
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24
include/linux/rcupdate.h
View File

@ -261,6 +261,10 @@ static inline void rcu_user_hooks_switch(struct task_struct *prev,
rcu_irq_exit(); \
} while (0)
#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP)
extern bool __rcu_is_watching(void);
#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) || defined(CONFIG_SMP) */
/*
* Infrastructure to implement the synchronize_() primitives in
* TREE_RCU and rcu_barrier_() primitives in TINY_RCU.
@ -297,10 +301,6 @@ static inline void destroy_rcu_head_on_stack(struct rcu_head *head)
}
#endif /* #else !CONFIG_DEBUG_OBJECTS_RCU_HEAD */
#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SMP)
extern int rcu_is_cpu_idle(void);
#endif /* #if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_SMP) */
#if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU)
bool rcu_lockdep_current_cpu_online(void);
#else /* #if defined(CONFIG_HOTPLUG_CPU) && defined(CONFIG_PROVE_RCU) */
@ -351,7 +351,7 @@ static inline int rcu_read_lock_held(void)
{
if (!debug_lockdep_rcu_enabled())
return 1;
if (rcu_is_cpu_idle())
if (!rcu_is_watching())
return 0;
if (!rcu_lockdep_current_cpu_online())
return 0;
@ -402,7 +402,7 @@ static inline int rcu_read_lock_sched_held(void)
if (!debug_lockdep_rcu_enabled())
return 1;
if (rcu_is_cpu_idle())
if (!rcu_is_watching())
return 0;
if (!rcu_lockdep_current_cpu_online())
return 0;
@ -771,7 +771,7 @@ static inline void rcu_read_lock(void)
__rcu_read_lock();
__acquire(RCU);
rcu_lock_acquire(&rcu_lock_map);
rcu_lockdep_assert(!rcu_is_cpu_idle(),
rcu_lockdep_assert(rcu_is_watching(),
"rcu_read_lock() used illegally while idle");
}
@ -792,7 +792,7 @@ static inline void rcu_read_lock(void)
*/
static inline void rcu_read_unlock(void)
{
rcu_lockdep_assert(!rcu_is_cpu_idle(),
rcu_lockdep_assert(rcu_is_watching(),
"rcu_read_unlock() used illegally while idle");
rcu_lock_release(&rcu_lock_map);
__release(RCU);
@ -821,7 +821,7 @@ static inline void rcu_read_lock_bh(void)
local_bh_disable();
__acquire(RCU_BH);
rcu_lock_acquire(&rcu_bh_lock_map);
rcu_lockdep_assert(!rcu_is_cpu_idle(),
rcu_lockdep_assert(rcu_is_watching(),
"rcu_read_lock_bh() used illegally while idle");
}
@ -832,7 +832,7 @@ static inline void rcu_read_lock_bh(void)
*/
static inline void rcu_read_unlock_bh(void)
{
rcu_lockdep_assert(!rcu_is_cpu_idle(),
rcu_lockdep_assert(rcu_is_watching(),
"rcu_read_unlock_bh() used illegally while idle");
rcu_lock_release(&rcu_bh_lock_map);
__release(RCU_BH);
@ -857,7 +857,7 @@ static inline void rcu_read_lock_sched(void)
preempt_disable();
__acquire(RCU_SCHED);
rcu_lock_acquire(&rcu_sched_lock_map);
rcu_lockdep_assert(!rcu_is_cpu_idle(),
rcu_lockdep_assert(rcu_is_watching(),
"rcu_read_lock_sched() used illegally while idle");
}
@ -875,7 +875,7 @@ static inline notrace void rcu_read_lock_sched_notrace(void)
*/
static inline void rcu_read_unlock_sched(void)
{
rcu_lockdep_assert(!rcu_is_cpu_idle(),
rcu_lockdep_assert(rcu_is_watching(),
"rcu_read_unlock_sched() used illegally while idle");
rcu_lock_release(&rcu_sched_lock_map);
__release(RCU_SCHED);

17
include/linux/rcutiny.h
View File

@ -132,4 +132,21 @@ static inline void rcu_scheduler_starting(void)
}
#endif /* #else #ifdef CONFIG_DEBUG_LOCK_ALLOC */
#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)
static inline bool rcu_is_watching(void)
{
return __rcu_is_watching();
}
#else /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
static inline bool rcu_is_watching(void)
{
return true;
}
#endif /* #else defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
#endif /* __LINUX_RCUTINY_H */

2
include/linux/rcutree.h
View File

@ -90,4 +90,6 @@ extern void exit_rcu(void);
extern void rcu_scheduler_starting(void);
extern int rcu_scheduler_active __read_mostly;
extern bool rcu_is_watching(void);
#endif /* __LINUX_RCUTREE_H */

4
kernel/lockdep.c
View File

@ -4224,7 +4224,7 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
printk("\n%srcu_scheduler_active = %d, debug_locks = %d\n",
!rcu_lockdep_current_cpu_online()
? "RCU used illegally from offline CPU!\n"
: rcu_is_cpu_idle()
: !rcu_is_watching()
? "RCU used illegally from idle CPU!\n"
: "",
rcu_scheduler_active, debug_locks);
@ -4247,7 +4247,7 @@ void lockdep_rcu_suspicious(const char *file, const int line, const char *s)
* So complain bitterly if someone does call rcu_read_lock(),
* rcu_read_lock_bh() and so on from extended quiescent states.
*/
if (rcu_is_cpu_idle())
if (!rcu_is_watching())
printk("RCU used illegally from extended quiescent state!\n");
lockdep_print_held_locks(curr);

2
kernel/rcupdate.c
View File

@ -148,7 +148,7 @@ int rcu_read_lock_bh_held(void)
{
if (!debug_lockdep_rcu_enabled())
return 1;
if (rcu_is_cpu_idle())
if (!rcu_is_watching())
return 0;
if (!rcu_lockdep_current_cpu_online())
return 0;

10
kernel/rcutiny.c
View File

@ -174,18 +174,18 @@ void rcu_irq_enter(void)
}
EXPORT_SYMBOL_GPL(rcu_irq_enter);
#ifdef CONFIG_DEBUG_LOCK_ALLOC
#if defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE)
/*
* Test whether RCU thinks that the current CPU is idle.
*/
int rcu_is_cpu_idle(void)
bool __rcu_is_watching(void)
{
return !rcu_dynticks_nesting;
return rcu_dynticks_nesting;
}
EXPORT_SYMBOL(rcu_is_cpu_idle);
EXPORT_SYMBOL(__rcu_is_watching);
#endif /* #ifdef CONFIG_DEBUG_LOCK_ALLOC */
#endif /* defined(CONFIG_DEBUG_LOCK_ALLOC) || defined(CONFIG_RCU_TRACE) */
/*
* Test whether the current CPU was interrupted from idle. Nested

23
kernel/rcutree.c
View File

@ -655,21 +655,34 @@ void rcu_nmi_exit(void)
}
/**
* rcu_is_cpu_idle - see if RCU thinks that the current CPU is idle
* __rcu_is_watching - are RCU read-side critical sections safe?
*
* Return true if RCU is watching the running CPU, which means that
* this CPU can safely enter RCU read-side critical sections. Unlike
* rcu_is_watching(), the caller of __rcu_is_watching() must have at
* least disabled preemption.
*/
bool __rcu_is_watching(void)
{
return atomic_read(this_cpu_ptr(&rcu_dynticks.dynticks)) & 0x1;
}
/**
* rcu_is_watching - see if RCU thinks that the current CPU is idle
*
* If the current CPU is in its idle loop and is neither in an interrupt
* or NMI handler, return true.
*/
int rcu_is_cpu_idle(void)
bool rcu_is_watching(void)
{
int ret;
preempt_disable();
ret = (atomic_read(&__get_cpu_var(rcu_dynticks).dynticks) & 0x1) == 0;
ret = __rcu_is_watching();
preempt_enable();
return ret;
}
EXPORT_SYMBOL(rcu_is_cpu_idle);
EXPORT_SYMBOL_GPL(rcu_is_watching);
#if defined(CONFIG_PROVE_RCU) && defined(CONFIG_HOTPLUG_CPU)
@ -2255,7 +2268,7 @@ static void __call_rcu_core(struct rcu_state *rsp, struct rcu_data *rdp,
* If called from an extended quiescent state, invoke the RCU
* core in order to force a re-evaluation of RCU's idleness.
*/
if (rcu_is_cpu_idle() && cpu_online(smp_processor_id()))
if (!rcu_is_watching() && cpu_online(smp_processor_id()))
invoke_rcu_core();
/* If interrupts were disabled or CPU offline, don't invoke RCU core. */

2
kernel/rcutree.h
View File

@ -104,6 +104,8 @@ struct rcu_dynticks {
/* idle-period nonlazy_posted snapshot. */
unsigned long last_accelerate;
/* Last jiffy CBs were accelerated. */
unsigned long last_advance_all;
/* Last jiffy CBs were all advanced. */
int tick_nohz_enabled_snap; /* Previously seen value from sysfs. */
#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
};

24
kernel/rcutree_plugin.h
View File

@ -1630,17 +1630,23 @@ module_param(rcu_idle_lazy_gp_delay, int, 0644);
extern int tick_nohz_enabled;
/*
* Try to advance callbacks for all flavors of RCU on the current CPU.
* Afterwards, if there are any callbacks ready for immediate invocation,
* return true.
* Try to advance callbacks for all flavors of RCU on the current CPU, but
* only if it has been awhile since the last time we did so. Afterwards,
* if there are any callbacks ready for immediate invocation, return true.
*/
static bool rcu_try_advance_all_cbs(void)
{
bool cbs_ready = false;
struct rcu_data *rdp;
struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
struct rcu_node *rnp;
struct rcu_state *rsp;
/* Exit early if we advanced recently. */
if (jiffies == rdtp->last_advance_all)
return 0;
rdtp->last_advance_all = jiffies;
for_each_rcu_flavor(rsp) {
rdp = this_cpu_ptr(rsp->rda);
rnp = rdp->mynode;
@ -1739,6 +1745,8 @@ static void rcu_prepare_for_idle(int cpu)
*/
if (rdtp->all_lazy &&
rdtp->nonlazy_posted != rdtp->nonlazy_posted_snap) {
rdtp->all_lazy = false;
rdtp->nonlazy_posted_snap = rdtp->nonlazy_posted;
invoke_rcu_core();
return;
}
@ -1768,17 +1776,11 @@ static void rcu_prepare_for_idle(int cpu)
*/
static void rcu_cleanup_after_idle(int cpu)
{
struct rcu_data *rdp;
struct rcu_state *rsp;
if (rcu_is_nocb_cpu(cpu))
return;
rcu_try_advance_all_cbs();
for_each_rcu_flavor(rsp) {
rdp = per_cpu_ptr(rsp->rda, cpu);
if (cpu_has_callbacks_ready_to_invoke(rdp))
invoke_rcu_core();
}
if (rcu_try_advance_all_cbs())
invoke_rcu_core();
}
/*