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Merge branch 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

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* 'core-fixes-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  futex: fix requeue_pi key imbalance
  futex: Fix typo in FUTEX_WAIT/WAKE_BITSET_PRIVATE definitions
  rcu: Place root rcu_node structure in separate lockdep class
  rcu: Make hot-unplugged CPU relinquish its own RCU callbacks
  rcu: Move rcu_barrier() to rcutree
  futex: Move exit_pi_state() call to release_mm()
  futex: Nullify robust lists after cleanup
  futex: Fix locking imbalance
  panic: Fix panic message visibility by calling bust_spinlocks(0) before dying
  rcu: Replace the rcu_barrier enum with pointer to call_rcu*() function
  rcu: Clean up code based on review feedback from Josh Triplett, part 4
  rcu: Clean up code based on review feedback from Josh Triplett, part 3
  rcu: Fix rcu_lock_map build failure on CONFIG_PROVE_LOCKING=y
  rcu: Clean up code to address Ingo's checkpatch feedback
  rcu: Clean up code based on review feedback from Josh Triplett, part 2
  rcu: Clean up code based on review feedback from Josh Triplett
This commit is contained in:
Linus Torvalds 2009-10-08 12:16:35 -07:00
commit f579bbcd9b
14 changed files with 405 additions and 316 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

4
include/linux/futex.h
View File

@ -33,8 +33,8 @@
#define FUTEX_LOCK_PI_PRIVATE (FUTEX_LOCK_PI | FUTEX_PRIVATE_FLAG)
#define FUTEX_UNLOCK_PI_PRIVATE (FUTEX_UNLOCK_PI | FUTEX_PRIVATE_FLAG)
#define FUTEX_TRYLOCK_PI_PRIVATE (FUTEX_TRYLOCK_PI | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITS | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITS | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAIT_BITSET_PRIVATE (FUTEX_WAIT_BITSET | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAKE_BITSET_PRIVATE (FUTEX_WAKE_BITSET | FUTEX_PRIVATE_FLAG)
#define FUTEX_WAIT_REQUEUE_PI_PRIVATE (FUTEX_WAIT_REQUEUE_PI | \
FUTEX_PRIVATE_FLAG)
#define FUTEX_CMP_REQUEUE_PI_PRIVATE (FUTEX_CMP_REQUEUE_PI | \

18
include/linux/rcupdate.h
View File

@ -77,7 +77,7 @@ extern int rcu_scheduler_active;
#error "Unknown RCU implementation specified to kernel configuration"
#endif
#define RCU_HEAD_INIT { .next = NULL, .func = NULL }
#define RCU_HEAD_INIT { .next = NULL, .func = NULL }
#define RCU_HEAD(head) struct rcu_head head = RCU_HEAD_INIT
#define INIT_RCU_HEAD(ptr) do { \
(ptr)->next = NULL; (ptr)->func = NULL; \
@ -129,12 +129,6 @@ static inline void rcu_read_lock(void)
rcu_read_acquire();
}
/**
* rcu_read_unlock - marks the end of an RCU read-side critical section.
*
* See rcu_read_lock() for more information.
*/
/*
* So where is rcu_write_lock()? It does not exist, as there is no
* way for writers to lock out RCU readers. This is a feature, not
@ -144,6 +138,12 @@ static inline void rcu_read_lock(void)
* used as well. RCU does not care how the writers keep out of each
* others' way, as long as they do so.
*/
/**
* rcu_read_unlock - marks the end of an RCU read-side critical section.
*
* See rcu_read_lock() for more information.
*/
static inline void rcu_read_unlock(void)
{
rcu_read_release();
@ -196,6 +196,8 @@ static inline void rcu_read_lock_sched(void)
__acquire(RCU_SCHED);
rcu_read_acquire();
}
/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
static inline notrace void rcu_read_lock_sched_notrace(void)
{
preempt_disable_notrace();
@ -213,6 +215,8 @@ static inline void rcu_read_unlock_sched(void)
__release(RCU_SCHED);
preempt_enable();
}
/* Used by lockdep and tracing: cannot be traced, cannot call lockdep. */
static inline notrace void rcu_read_unlock_sched_notrace(void)
{
__release(RCU_SCHED);

13
include/linux/rcutree.h
View File

@ -30,10 +30,14 @@
#ifndef __LINUX_RCUTREE_H
#define __LINUX_RCUTREE_H
struct notifier_block;
extern void rcu_sched_qs(int cpu);
extern void rcu_bh_qs(int cpu);
extern int rcu_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu);
extern int rcu_needs_cpu(int cpu);
extern int rcu_expedited_torture_stats(char *page);
#ifdef CONFIG_TREE_PREEMPT_RCU
@ -85,16 +89,11 @@ static inline void synchronize_rcu_bh_expedited(void)
extern void __rcu_init(void);
extern void rcu_check_callbacks(int cpu, int user);
extern void rcu_restart_cpu(int cpu);
extern long rcu_batches_completed(void);
extern long rcu_batches_completed_bh(void);
extern long rcu_batches_completed_sched(void);
static inline void rcu_init_sched(void)
{
}
#ifdef CONFIG_NO_HZ
void rcu_enter_nohz(void);
void rcu_exit_nohz(void);
@ -107,7 +106,7 @@ static inline void rcu_exit_nohz(void)
}
#endif /* CONFIG_NO_HZ */
/* A context switch is a grace period for rcutree. */
/* A context switch is a grace period for RCU-sched and RCU-bh. */
static inline int rcu_blocking_is_gp(void)
{
return num_online_cpus() == 1;

1
init/main.c
View File

@ -778,7 +778,6 @@ static void __init do_initcalls(void)
*/
static void __init do_basic_setup(void)
{
rcu_init_sched(); /* needed by module_init stage. */
init_workqueues();
cpuset_init_smp();
usermodehelper_init();

2
kernel/exit.c
View File

@ -991,8 +991,6 @@ NORET_TYPE void do_exit(long code)
tsk->mempolicy = NULL;
#endif
#ifdef CONFIG_FUTEX
if (unlikely(!list_empty(&tsk->pi_state_list)))
exit_pi_state_list(tsk);
if (unlikely(current->pi_state_cache))
kfree(current->pi_state_cache);
#endif

10
kernel/fork.c
View File

@ -570,12 +570,18 @@ void mm_release(struct task_struct *tsk, struct mm_struct *mm)
/* Get rid of any futexes when releasing the mm */
#ifdef CONFIG_FUTEX
if (unlikely(tsk->robust_list))
if (unlikely(tsk->robust_list)) {
exit_robust_list(tsk);
tsk->robust_list = NULL;
}
#ifdef CONFIG_COMPAT
if (unlikely(tsk->compat_robust_list))
if (unlikely(tsk->compat_robust_list)) {
compat_exit_robust_list(tsk);
tsk->compat_robust_list = NULL;
}
#endif
if (unlikely(!list_empty(&tsk->pi_state_list)))
exit_pi_state_list(tsk);
#endif
/* Get rid of any cached register state */

3
kernel/futex.c
View File

@ -916,8 +916,8 @@ retry:
hb1 = hash_futex(&key1);
hb2 = hash_futex(&key2);
double_lock_hb(hb1, hb2);
retry_private:
double_lock_hb(hb1, hb2);
op_ret = futex_atomic_op_inuser(op, uaddr2);
if (unlikely(op_ret < 0)) {
@ -2117,7 +2117,6 @@ int handle_early_requeue_pi_wakeup(struct futex_hash_bucket *hb,
* Unqueue the futex_q and determine which it was.
*/
plist_del(&q->list, &q->list.plist);
drop_futex_key_refs(&q->key);
if (timeout && !timeout->task)
ret = -ETIMEDOUT;

3
kernel/panic.c
View File

@ -90,6 +90,8 @@ NORET_TYPE void panic(const char * fmt, ...)
atomic_notifier_call_chain(&panic_notifier_list, 0, buf);
bust_spinlocks(0);
if (!panic_blink)
panic_blink = no_blink;
@ -136,7 +138,6 @@ NORET_TYPE void panic(const char * fmt, ...)
mdelay(1);
i++;
}
bust_spinlocks(0);
}
EXPORT_SYMBOL(panic);

140
kernel/rcupdate.c
View File

@ -46,22 +46,15 @@
#include <linux/module.h>
#include <linux/kernel_stat.h>
enum rcu_barrier {
RCU_BARRIER_STD,
RCU_BARRIER_BH,
RCU_BARRIER_SCHED,
};
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
struct lockdep_map rcu_lock_map =
STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
EXPORT_SYMBOL_GPL(rcu_lock_map);
#endif
static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
static struct completion rcu_barrier_completion;
int rcu_scheduler_active __read_mostly;
static atomic_t rcu_migrate_type_count = ATOMIC_INIT(0);
static struct rcu_head rcu_migrate_head[3];
static DECLARE_WAIT_QUEUE_HEAD(rcu_migrate_wq);
/*
* Awaken the corresponding synchronize_rcu() instance now that a
* grace period has elapsed.
@ -164,129 +157,10 @@ void synchronize_rcu_bh(void)
}
EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
static void rcu_barrier_callback(struct rcu_head *notused)
{
if (atomic_dec_and_test(&rcu_barrier_cpu_count))
complete(&rcu_barrier_completion);
}
/*
* Called with preemption disabled, and from cross-cpu IRQ context.
*/
static void rcu_barrier_func(void *type)
{
int cpu = smp_processor_id();
struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu);
atomic_inc(&rcu_barrier_cpu_count);
switch ((enum rcu_barrier)type) {
case RCU_BARRIER_STD:
call_rcu(head, rcu_barrier_callback);
break;
case RCU_BARRIER_BH:
call_rcu_bh(head, rcu_barrier_callback);
break;
case RCU_BARRIER_SCHED:
call_rcu_sched(head, rcu_barrier_callback);
break;
}
}
static inline void wait_migrated_callbacks(void)
{
wait_event(rcu_migrate_wq, !atomic_read(&rcu_migrate_type_count));
smp_mb(); /* In case we didn't sleep. */
}
/*
* Orchestrate the specified type of RCU barrier, waiting for all
* RCU callbacks of the specified type to complete.
*/
static void _rcu_barrier(enum rcu_barrier type)
{
BUG_ON(in_interrupt());
/* Take cpucontrol mutex to protect against CPU hotplug */
mutex_lock(&rcu_barrier_mutex);
init_completion(&rcu_barrier_completion);
/*
* Initialize rcu_barrier_cpu_count to 1, then invoke
* rcu_barrier_func() on each CPU, so that each CPU also has
* incremented rcu_barrier_cpu_count. Only then is it safe to
* decrement rcu_barrier_cpu_count -- otherwise the first CPU
* might complete its grace period before all of the other CPUs
* did their increment, causing this function to return too
* early.
*/
atomic_set(&rcu_barrier_cpu_count, 1);
on_each_cpu(rcu_barrier_func, (void *)type, 1);
if (atomic_dec_and_test(&rcu_barrier_cpu_count))
complete(&rcu_barrier_completion);
wait_for_completion(&rcu_barrier_completion);
mutex_unlock(&rcu_barrier_mutex);
wait_migrated_callbacks();
}
/**
* rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
*/
void rcu_barrier(void)
{
_rcu_barrier(RCU_BARRIER_STD);
}
EXPORT_SYMBOL_GPL(rcu_barrier);
/**
* rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
*/
void rcu_barrier_bh(void)
{
_rcu_barrier(RCU_BARRIER_BH);
}
EXPORT_SYMBOL_GPL(rcu_barrier_bh);
/**
* rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
*/
void rcu_barrier_sched(void)
{
_rcu_barrier(RCU_BARRIER_SCHED);
}
EXPORT_SYMBOL_GPL(rcu_barrier_sched);
static void rcu_migrate_callback(struct rcu_head *notused)
{
if (atomic_dec_and_test(&rcu_migrate_type_count))
wake_up(&rcu_migrate_wq);
}
extern int rcu_cpu_notify(struct notifier_block *self,
unsigned long action, void *hcpu);
static int __cpuinit rcu_barrier_cpu_hotplug(struct notifier_block *self,
unsigned long action, void *hcpu)
{
rcu_cpu_notify(self, action, hcpu);
if (action == CPU_DYING) {
/*
* preempt_disable() in on_each_cpu() prevents stop_machine(),
* so when "on_each_cpu(rcu_barrier_func, (void *)type, 1);"
* returns, all online cpus have queued rcu_barrier_func(),
* and the dead cpu(if it exist) queues rcu_migrate_callback()s.
*
* These callbacks ensure _rcu_barrier() waits for all
* RCU callbacks of the specified type to complete.
*/
atomic_set(&rcu_migrate_type_count, 3);
call_rcu_bh(rcu_migrate_head, rcu_migrate_callback);
call_rcu_sched(rcu_migrate_head + 1, rcu_migrate_callback);
call_rcu(rcu_migrate_head + 2, rcu_migrate_callback);
} else if (action == CPU_DOWN_PREPARE) {
/* Don't need to wait until next removal operation. */
/* rcu_migrate_head is protected by cpu_add_remove_lock */
wait_migrated_callbacks();
}
return NOTIFY_OK;
return rcu_cpu_notify(self, action, hcpu);
}
void __init rcu_init(void)

4
kernel/rcutorture.c
View File

@ -606,8 +606,6 @@ static struct rcu_torture_ops sched_ops_sync = {
.name = "sched_sync"
};
extern int rcu_expedited_torture_stats(char *page);
static struct rcu_torture_ops sched_expedited_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
@ -650,7 +648,7 @@ rcu_torture_writer(void *arg)
old_rp = rcu_torture_current;
rp->rtort_mbtest = 1;
rcu_assign_pointer(rcu_torture_current, rp);
smp_wmb();
smp_wmb(); /* Mods to old_rp must follow rcu_assign_pointer() */
if (old_rp) {
i = old_rp->rtort_pipe_count;
if (i > RCU_TORTURE_PIPE_LEN)

330
kernel/rcutree.c
View File

@ -49,13 +49,6 @@
#include "rcutree.h"
#ifdef CONFIG_DEBUG_LOCK_ALLOC
static struct lock_class_key rcu_lock_key;
struct lockdep_map rcu_lock_map =
STATIC_LOCKDEP_MAP_INIT("rcu_read_lock", &rcu_lock_key);
EXPORT_SYMBOL_GPL(rcu_lock_map);
#endif
/* Data structures. */
#define RCU_STATE_INITIALIZER(name) { \
@ -70,6 +63,9 @@ EXPORT_SYMBOL_GPL(rcu_lock_map);
.gpnum = -300, \
.completed = -300, \
.onofflock = __SPIN_LOCK_UNLOCKED(&name.onofflock), \
.orphan_cbs_list = NULL, \
.orphan_cbs_tail = &name.orphan_cbs_list, \
.orphan_qlen = 0, \
.fqslock = __SPIN_LOCK_UNLOCKED(&name.fqslock), \
.n_force_qs = 0, \
.n_force_qs_ngp = 0, \
@ -81,24 +77,16 @@ DEFINE_PER_CPU(struct rcu_data, rcu_sched_data);
struct rcu_state rcu_bh_state = RCU_STATE_INITIALIZER(rcu_bh_state);
DEFINE_PER_CPU(struct rcu_data, rcu_bh_data);
extern long rcu_batches_completed_sched(void);
static struct rcu_node *rcu_get_root(struct rcu_state *rsp);
static void cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp,
struct rcu_node *rnp, unsigned long flags);
static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags);
#ifdef CONFIG_HOTPLUG_CPU
static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
static void __rcu_process_callbacks(struct rcu_state *rsp,
struct rcu_data *rdp);
static void __call_rcu(struct rcu_head *head,
void (*func)(struct rcu_head *rcu),
struct rcu_state *rsp);
static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp);
static void __cpuinit rcu_init_percpu_data(int cpu, struct rcu_state *rsp,
int preemptable);
#include "rcutree_plugin.h"
/*
* Return true if an RCU grace period is in progress. The ACCESS_ONCE()s
* permit this function to be invoked without holding the root rcu_node
* structure's ->lock, but of course results can be subject to change.
*/
static int rcu_gp_in_progress(struct rcu_state *rsp)
{
return ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum);
}
/*
* Note a quiescent state. Because we do not need to know
@ -137,6 +125,10 @@ static int blimit = 10; /* Maximum callbacks per softirq. */
static int qhimark = 10000; /* If this many pending, ignore blimit. */
static int qlowmark = 100; /* Once only this many pending, use blimit. */
module_param(blimit, int, 0);
module_param(qhimark, int, 0);
module_param(qlowmark, int, 0);
static void force_quiescent_state(struct rcu_state *rsp, int relaxed);
static int rcu_pending(int cpu);
@ -173,9 +165,7 @@ cpu_has_callbacks_ready_to_invoke(struct rcu_data *rdp)
static int
cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
{
/* ACCESS_ONCE() because we are accessing outside of lock. */
return *rdp->nxttail[RCU_DONE_TAIL] &&
ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum);
return *rdp->nxttail[RCU_DONE_TAIL] && !rcu_gp_in_progress(rsp);
}
/*
@ -369,7 +359,7 @@ static long dyntick_recall_completed(struct rcu_state *rsp)
/*
* Snapshot the specified CPU's dynticks counter so that we can later
* credit them with an implicit quiescent state. Return 1 if this CPU
* is already in a quiescent state courtesy of dynticks idle mode.
* is in dynticks idle mode, which is an extended quiescent state.
*/
static int dyntick_save_progress_counter(struct rcu_data *rdp)
{
@ -475,30 +465,34 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
long delta;
unsigned long flags;
struct rcu_node *rnp = rcu_get_root(rsp);
struct rcu_node *rnp_cur = rsp->level[NUM_RCU_LVLS - 1];
struct rcu_node *rnp_end = &rsp->node[NUM_RCU_NODES];
/* Only let one CPU complain about others per time interval. */
spin_lock_irqsave(&rnp->lock, flags);
delta = jiffies - rsp->jiffies_stall;
if (delta < RCU_STALL_RAT_DELAY || rsp->gpnum == rsp->completed) {
if (delta < RCU_STALL_RAT_DELAY || !rcu_gp_in_progress(rsp)) {
spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
rsp->jiffies_stall = jiffies + RCU_SECONDS_TILL_STALL_RECHECK;
/*
* Now rat on any tasks that got kicked up to the root rcu_node
* due to CPU offlining.
*/
rcu_print_task_stall(rnp);
spin_unlock_irqrestore(&rnp->lock, flags);
/* OK, time to rat on our buddy... */
printk(KERN_ERR "INFO: RCU detected CPU stalls:");
for (; rnp_cur < rnp_end; rnp_cur++) {
rcu_for_each_leaf_node(rsp, rnp) {
rcu_print_task_stall(rnp);
if (rnp_cur->qsmask == 0)
if (rnp->qsmask == 0)
continue;
for (cpu = 0; cpu <= rnp_cur->grphi - rnp_cur->grplo; cpu++)
if (rnp_cur->qsmask & (1UL << cpu))
printk(" %d", rnp_cur->grplo + cpu);
for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
if (rnp->qsmask & (1UL << cpu))
printk(" %d", rnp->grplo + cpu);
}
printk(" (detected by %d, t=%ld jiffies)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start));
@ -537,8 +531,7 @@ static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
/* We haven't checked in, so go dump stack. */
print_cpu_stall(rsp);
} else if (rsp->gpnum != rsp->completed &&
delta >= RCU_STALL_RAT_DELAY) {
} else if (rcu_gp_in_progress(rsp) && delta >= RCU_STALL_RAT_DELAY) {
/* They had two time units to dump stack, so complain. */
print_other_cpu_stall(rsp);
@ -617,9 +610,15 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
note_new_gpnum(rsp, rdp);
/*
* Because we are first, we know that all our callbacks will
* be covered by this upcoming grace period, even the ones
* that were registered arbitrarily recently.
* Because this CPU just now started the new grace period, we know
* that all of its callbacks will be covered by this upcoming grace
* period, even the ones that were registered arbitrarily recently.
* Therefore, advance all outstanding callbacks to RCU_WAIT_TAIL.
*
* Other CPUs cannot be sure exactly when the grace period started.
* Therefore, their recently registered callbacks must pass through
* an additional RCU_NEXT_READY stage, so that they will be handled
* by the next RCU grace period.
*/
rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
@ -657,7 +656,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
* one corresponding to this CPU, due to the fact that we have
* irqs disabled.
*/
for (rnp = &rsp->node[0]; rnp < &rsp->node[NUM_RCU_NODES]; rnp++) {
rcu_for_each_node_breadth_first(rsp, rnp) {
spin_lock(&rnp->lock); /* irqs already disabled. */
rcu_preempt_check_blocked_tasks(rnp);
rnp->qsmask = rnp->qsmaskinit;
@ -703,9 +702,9 @@ rcu_process_gp_end(struct rcu_state *rsp, struct rcu_data *rdp)
* hold rnp->lock, as required by rcu_start_gp(), which will release it.
*/
static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags)
__releases(rnp->lock)
__releases(rcu_get_root(rsp)->lock)
{
WARN_ON_ONCE(rsp->completed == rsp->gpnum);
WARN_ON_ONCE(!rcu_gp_in_progress(rsp));
rsp->completed = rsp->gpnum;
rcu_process_gp_end(rsp, rsp->rda[smp_processor_id()]);
rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */
@ -841,18 +840,64 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
#ifdef CONFIG_HOTPLUG_CPU
/*
* Move a dying CPU's RCU callbacks to the ->orphan_cbs_list for the
* specified flavor of RCU. The callbacks will be adopted by the next
* _rcu_barrier() invocation or by the CPU_DEAD notifier, whichever
* comes first. Because this is invoked from the CPU_DYING notifier,
* irqs are already disabled.
*/
static void rcu_send_cbs_to_orphanage(struct rcu_state *rsp)
{
int i;
struct rcu_data *rdp = rsp->rda[smp_processor_id()];
if (rdp->nxtlist == NULL)
return; /* irqs disabled, so comparison is stable. */
spin_lock(&rsp->onofflock); /* irqs already disabled. */
*rsp->orphan_cbs_tail = rdp->nxtlist;
rsp->orphan_cbs_tail = rdp->nxttail[RCU_NEXT_TAIL];
rdp->nxtlist = NULL;
for (i = 0; i < RCU_NEXT_SIZE; i++)
rdp->nxttail[i] = &rdp->nxtlist;
rsp->orphan_qlen += rdp->qlen;
rdp->qlen = 0;
spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
}
/*
* Adopt previously orphaned RCU callbacks.
*/
static void rcu_adopt_orphan_cbs(struct rcu_state *rsp)
{
unsigned long flags;
struct rcu_data *rdp;
spin_lock_irqsave(&rsp->onofflock, flags);
rdp = rsp->rda[smp_processor_id()];
if (rsp->orphan_cbs_list == NULL) {
spin_unlock_irqrestore(&rsp->onofflock, flags);
return;
}
*rdp->nxttail[RCU_NEXT_TAIL] = rsp->orphan_cbs_list;
rdp->nxttail[RCU_NEXT_TAIL] = rsp->orphan_cbs_tail;
rdp->qlen += rsp->orphan_qlen;
rsp->orphan_cbs_list = NULL;
rsp->orphan_cbs_tail = &rsp->orphan_cbs_list;
rsp->orphan_qlen = 0;
spin_unlock_irqrestore(&rsp->onofflock, flags);
}
/*
* Remove the outgoing CPU from the bitmasks in the rcu_node hierarchy
* and move all callbacks from the outgoing CPU to the current one.
*/
static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
{
int i;
unsigned long flags;
long lastcomp;
unsigned long mask;
struct rcu_data *rdp = rsp->rda[cpu];
struct rcu_data *rdp_me;
struct rcu_node *rnp;
/* Exclude any attempts to start a new grace period. */
@ -875,32 +920,9 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp)
} while (rnp != NULL);
lastcomp = rsp->completed;
spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
spin_unlock_irqrestore(&rsp->onofflock, flags);
/*
* Move callbacks from the outgoing CPU to the running CPU.
* Note that the outgoing CPU is now quiscent, so it is now
* (uncharacteristically) safe to access its rcu_data structure.
* Note also that we must carefully retain the order of the
* outgoing CPU's callbacks in order for rcu_barrier() to work
* correctly. Finally, note that we start all the callbacks
* afresh, even those that have passed through a grace period
* and are therefore ready to invoke. The theory is that hotplug
* events are rare, and that if they are frequent enough to
* indefinitely delay callbacks, you have far worse things to
* be worrying about.
*/
rdp_me = rsp->rda[smp_processor_id()];
if (rdp->nxtlist != NULL) {
*rdp_me->nxttail[RCU_NEXT_TAIL] = rdp->nxtlist;
rdp_me->nxttail[RCU_NEXT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
rdp->nxtlist = NULL;
for (i = 0; i < RCU_NEXT_SIZE; i++)
rdp->nxttail[i] = &rdp->nxtlist;
rdp_me->qlen += rdp->qlen;
rdp->qlen = 0;
}
local_irq_restore(flags);
rcu_adopt_orphan_cbs(rsp);
}
/*
@ -918,6 +940,14 @@ static void rcu_offline_cpu(int cpu)
#else /* #ifdef CONFIG_HOTPLUG_CPU */
static void rcu_send_cbs_to_orphanage(struct rcu_state *rsp)
{
}
static void rcu_adopt_orphan_cbs(struct rcu_state *rsp)
{
}
static void rcu_offline_cpu(int cpu)
{
}
@ -1050,33 +1080,32 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp,
int cpu;
unsigned long flags;
unsigned long mask;
struct rcu_node *rnp_cur = rsp->level[NUM_RCU_LVLS - 1];
struct rcu_node *rnp_end = &rsp->node[NUM_RCU_NODES];
struct rcu_node *rnp;
for (; rnp_cur < rnp_end; rnp_cur++) {
rcu_for_each_leaf_node(rsp, rnp) {
mask = 0;
spin_lock_irqsave(&rnp_cur->lock, flags);
spin_lock_irqsave(&rnp->lock, flags);
if (rsp->completed != lastcomp) {
spin_unlock_irqrestore(&rnp_cur->lock, flags);
spin_unlock_irqrestore(&rnp->lock, flags);
return 1;
}
if (rnp_cur->qsmask == 0) {
spin_unlock_irqrestore(&rnp_cur->lock, flags);
if (rnp->qsmask == 0) {
spin_unlock_irqrestore(&rnp->lock, flags);
continue;
}
cpu = rnp_cur->grplo;
cpu = rnp->grplo;
bit = 1;
for (; cpu <= rnp_cur->grphi; cpu++, bit <<= 1) {
if ((rnp_cur->qsmask & bit) != 0 && f(rsp->rda[cpu]))
for (; cpu <= rnp->grphi; cpu++, bit <<= 1) {
if ((rnp->qsmask & bit) != 0 && f(rsp->rda[cpu]))
mask |= bit;
}
if (mask != 0 && rsp->completed == lastcomp) {
/* cpu_quiet_msk() releases rnp_cur->lock. */
cpu_quiet_msk(mask, rsp, rnp_cur, flags);
/* cpu_quiet_msk() releases rnp->lock. */
cpu_quiet_msk(mask, rsp, rnp, flags);
continue;
}
spin_unlock_irqrestore(&rnp_cur->lock, flags);
spin_unlock_irqrestore(&rnp->lock, flags);
}
return 0;
}
@ -1092,7 +1121,7 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed)
struct rcu_node *rnp = rcu_get_root(rsp);
u8 signaled;
if (ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum))
if (!rcu_gp_in_progress(rsp))
return; /* No grace period in progress, nothing to force. */
if (!spin_trylock_irqsave(&rsp->fqslock, flags)) {
rsp->n_force_qs_lh++; /* Inexact, can lose counts. Tough! */
@ -1251,7 +1280,7 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu),
rdp->nxttail[RCU_NEXT_TAIL] = &head->next;
/* Start a new grace period if one not already started. */
if (ACCESS_ONCE(rsp->completed) == ACCESS_ONCE(rsp->gpnum)) {
if (!rcu_gp_in_progress(rsp)) {
unsigned long nestflag;
struct rcu_node *rnp_root = rcu_get_root(rsp);
@ -1331,7 +1360,7 @@ static int __rcu_pending(struct rcu_state *rsp, struct rcu_data *rdp)
}
/* Has an RCU GP gone long enough to send resched IPIs &c? */
if (ACCESS_ONCE(rsp->completed) != ACCESS_ONCE(rsp->gpnum) &&
if (rcu_gp_in_progress(rsp) &&
((long)(ACCESS_ONCE(rsp->jiffies_force_qs) - jiffies) < 0)) {
rdp->n_rp_need_fqs++;
return 1;
@ -1368,6 +1397,82 @@ int rcu_needs_cpu(int cpu)
rcu_preempt_needs_cpu(cpu);
}
static DEFINE_PER_CPU(struct rcu_head, rcu_barrier_head) = {NULL};
static atomic_t rcu_barrier_cpu_count;
static DEFINE_MUTEX(rcu_barrier_mutex);
static struct completion rcu_barrier_completion;
static void rcu_barrier_callback(struct rcu_head *notused)
{
if (atomic_dec_and_test(&rcu_barrier_cpu_count))
complete(&rcu_barrier_completion);
}
/*
* Called with preemption disabled, and from cross-cpu IRQ context.
*/
static void rcu_barrier_func(void *type)
{
int cpu = smp_processor_id();
struct rcu_head *head = &per_cpu(rcu_barrier_head, cpu);
void (*call_rcu_func)(struct rcu_head *head,
void (*func)(struct rcu_head *head));
atomic_inc(&rcu_barrier_cpu_count);
call_rcu_func = type;
call_rcu_func(head, rcu_barrier_callback);
}
/*
* Orchestrate the specified type of RCU barrier, waiting for all
* RCU callbacks of the specified type to complete.
*/
static void _rcu_barrier(struct rcu_state *rsp,
void (*call_rcu_func)(struct rcu_head *head,
void (*func)(struct rcu_head *head)))
{
BUG_ON(in_interrupt());
/* Take mutex to serialize concurrent rcu_barrier() requests. */
mutex_lock(&rcu_barrier_mutex);
init_completion(&rcu_barrier_completion);
/*
* Initialize rcu_barrier_cpu_count to 1, then invoke
* rcu_barrier_func() on each CPU, so that each CPU also has
* incremented rcu_barrier_cpu_count. Only then is it safe to
* decrement rcu_barrier_cpu_count -- otherwise the first CPU
* might complete its grace period before all of the other CPUs
* did their increment, causing this function to return too
* early.
*/
atomic_set(&rcu_barrier_cpu_count, 1);
preempt_disable(); /* stop CPU_DYING from filling orphan_cbs_list */
rcu_adopt_orphan_cbs(rsp);
on_each_cpu(rcu_barrier_func, (void *)call_rcu_func, 1);
preempt_enable(); /* CPU_DYING can again fill orphan_cbs_list */
if (atomic_dec_and_test(&rcu_barrier_cpu_count))
complete(&rcu_barrier_completion);
wait_for_completion(&rcu_barrier_completion);
mutex_unlock(&rcu_barrier_mutex);
}
/**
* rcu_barrier_bh - Wait until all in-flight call_rcu_bh() callbacks complete.
*/
void rcu_barrier_bh(void)
{
_rcu_barrier(&rcu_bh_state, call_rcu_bh);
}
EXPORT_SYMBOL_GPL(rcu_barrier_bh);
/**
* rcu_barrier_sched - Wait for in-flight call_rcu_sched() callbacks.
*/
void rcu_barrier_sched(void)
{
_rcu_barrier(&rcu_sched_state, call_rcu_sched);
}
EXPORT_SYMBOL_GPL(rcu_barrier_sched);
/*
* Do boot-time initialization of a CPU's per-CPU RCU data.
*/
@ -1464,6 +1569,22 @@ int __cpuinit rcu_cpu_notify(struct notifier_block *self,
case CPU_UP_PREPARE_FROZEN:
rcu_online_cpu(cpu);
break;
case CPU_DYING:
case CPU_DYING_FROZEN:
/*
* preempt_disable() in _rcu_barrier() prevents stop_machine(),
* so when "on_each_cpu(rcu_barrier_func, (void *)type, 1);"
* returns, all online cpus have queued rcu_barrier_func().
* The dying CPU clears its cpu_online_mask bit and
* moves all of its RCU callbacks to ->orphan_cbs_list
* in the context of stop_machine(), so subsequent calls
* to _rcu_barrier() will adopt these callbacks and only
* then queue rcu_barrier_func() on all remaining CPUs.
*/
rcu_send_cbs_to_orphanage(&rcu_bh_state);
rcu_send_cbs_to_orphanage(&rcu_sched_state);
rcu_preempt_send_cbs_to_orphanage();
break;
case CPU_DEAD:
case CPU_DEAD_FROZEN:
case CPU_UP_CANCELED:
@ -1526,7 +1647,8 @@ static void __init rcu_init_one(struct rcu_state *rsp)
cpustride *= rsp->levelspread[i];
rnp = rsp->level[i];
for (j = 0; j < rsp->levelcnt[i]; j++, rnp++) {
spin_lock_init(&rnp->lock);
if (rnp != rcu_get_root(rsp))
spin_lock_init(&rnp->lock);
rnp->gpnum = 0;
rnp->qsmask = 0;
rnp->qsmaskinit = 0;
@ -1549,6 +1671,7 @@ static void __init rcu_init_one(struct rcu_state *rsp)
INIT_LIST_HEAD(&rnp->blocked_tasks[1]);
}
}
spin_lock_init(&rcu_get_root(rsp)->lock);
}
/*
@ -1558,6 +1681,10 @@ static void __init rcu_init_one(struct rcu_state *rsp)
*/
#define RCU_INIT_FLAVOR(rsp, rcu_data) \
do { \
int i; \
int j; \
struct rcu_node *rnp; \
\
rcu_init_one(rsp); \
rnp = (rsp)->level[NUM_RCU_LVLS - 1]; \
j = 0; \
@ -1570,31 +1697,8 @@ do { \
} \
} while (0)
#ifdef CONFIG_TREE_PREEMPT_RCU
void __init __rcu_init_preempt(void)
{
int i; /* All used by RCU_INIT_FLAVOR(). */
int j;
struct rcu_node *rnp;
RCU_INIT_FLAVOR(&rcu_preempt_state, rcu_preempt_data);
}
#else /* #ifdef CONFIG_TREE_PREEMPT_RCU */
void __init __rcu_init_preempt(void)
{
}
#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */
void __init __rcu_init(void)
{
int i; /* All used by RCU_INIT_FLAVOR(). */
int j;
struct rcu_node *rnp;
rcu_bootup_announce();
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
printk(KERN_INFO "RCU-based detection of stalled CPUs is enabled.\n");
@ -1605,6 +1709,4 @@ void __init __rcu_init(void)
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
}
module_param(blimit, int, 0);
module_param(qhimark, int, 0);
module_param(qlowmark, int, 0);
#include "rcutree_plugin.h"

86
kernel/rcutree.h
View File

@ -48,14 +48,14 @@
#elif NR_CPUS <= RCU_FANOUT_SQ
# define NUM_RCU_LVLS 2
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 (((NR_CPUS) + RCU_FANOUT - 1) / RCU_FANOUT)
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT)
# define NUM_RCU_LVL_2 (NR_CPUS)
# define NUM_RCU_LVL_3 0
#elif NR_CPUS <= RCU_FANOUT_CUBE
# define NUM_RCU_LVLS 3
# define NUM_RCU_LVL_0 1
# define NUM_RCU_LVL_1 (((NR_CPUS) + RCU_FANOUT_SQ - 1) / RCU_FANOUT_SQ)
# define NUM_RCU_LVL_2 (((NR_CPUS) + (RCU_FANOUT) - 1) / (RCU_FANOUT))
# define NUM_RCU_LVL_1 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT_SQ)
# define NUM_RCU_LVL_2 DIV_ROUND_UP(NR_CPUS, RCU_FANOUT)
# define NUM_RCU_LVL_3 NR_CPUS
#else
# error "CONFIG_RCU_FANOUT insufficient for NR_CPUS"
@ -79,15 +79,21 @@ struct rcu_dynticks {
* Definition for node within the RCU grace-period-detection hierarchy.
*/
struct rcu_node {
spinlock_t lock;
spinlock_t lock; /* Root rcu_node's lock protects some */
/* rcu_state fields as well as following. */
long gpnum; /* Current grace period for this node. */
/* This will either be equal to or one */
/* behind the root rcu_node's gpnum. */
unsigned long qsmask; /* CPUs or groups that need to switch in */
/* order for current grace period to proceed.*/
/* In leaf rcu_node, each bit corresponds to */
/* an rcu_data structure, otherwise, each */
/* bit corresponds to a child rcu_node */
/* structure. */
unsigned long qsmaskinit;
/* Per-GP initialization for qsmask. */
unsigned long grpmask; /* Mask to apply to parent qsmask. */
/* Only one bit will be set in this mask. */
int grplo; /* lowest-numbered CPU or group here. */
int grphi; /* highest-numbered CPU or group here. */
u8 grpnum; /* CPU/group number for next level up. */
@ -95,8 +101,23 @@ struct rcu_node {
struct rcu_node *parent;
struct list_head blocked_tasks[2];
/* Tasks blocked in RCU read-side critsect. */
/* Grace period number (->gpnum) x blocked */
/* by tasks on the (x & 0x1) element of the */
/* blocked_tasks[] array. */
} ____cacheline_internodealigned_in_smp;
/*
* Do a full breadth-first scan of the rcu_node structures for the
* specified rcu_state structure.
*/
#define rcu_for_each_node_breadth_first(rsp, rnp) \
for ((rnp) = &(rsp)->node[0]; \
(rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
#define rcu_for_each_leaf_node(rsp, rnp) \
for ((rnp) = (rsp)->level[NUM_RCU_LVLS - 1]; \
(rnp) < &(rsp)->node[NUM_RCU_NODES]; (rnp)++)
/* Index values for nxttail array in struct rcu_data. */
#define RCU_DONE_TAIL 0 /* Also RCU_WAIT head. */
#define RCU_WAIT_TAIL 1 /* Also RCU_NEXT_READY head. */
@ -126,19 +147,22 @@ struct rcu_data {
* Any of the partitions might be empty, in which case the
* pointer to that partition will be equal to the pointer for
* the following partition. When the list is empty, all of
* the nxttail elements point to nxtlist, which is NULL.
* the nxttail elements point to the ->nxtlist pointer itself,
* which in that case is NULL.
*
* [*nxttail[RCU_NEXT_READY_TAIL], NULL = *nxttail[RCU_NEXT_TAIL]):
* Entries that might have arrived after current GP ended
* [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
* Entries known to have arrived before current GP ended
* [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
* Entries that batch # <= ->completed - 1: waiting for current GP
* [nxtlist, *nxttail[RCU_DONE_TAIL]):
* Entries that batch # <= ->completed
* The grace period for these entries has completed, and
* the other grace-period-completed entries may be moved
* here temporarily in rcu_process_callbacks().
* [*nxttail[RCU_DONE_TAIL], *nxttail[RCU_WAIT_TAIL]):
* Entries that batch # <= ->completed - 1: waiting for current GP
* [*nxttail[RCU_WAIT_TAIL], *nxttail[RCU_NEXT_READY_TAIL]):
* Entries known to have arrived before current GP ended
* [*nxttail[RCU_NEXT_READY_TAIL], *nxttail[RCU_NEXT_TAIL]):
* Entries that might have arrived after current GP ended
* Note that the value of *nxttail[RCU_NEXT_TAIL] will
* always be NULL, as this is the end of the list.
*/
struct rcu_head *nxtlist;
struct rcu_head **nxttail[RCU_NEXT_SIZE];
@ -216,8 +240,19 @@ struct rcu_state {
/* Force QS state. */
long gpnum; /* Current gp number. */
long completed; /* # of last completed gp. */
/* End of fields guarded by root rcu_node's lock. */
spinlock_t onofflock; /* exclude on/offline and */
/* starting new GP. */
/* starting new GP. Also */
/* protects the following */
/* orphan_cbs fields. */
struct rcu_head *orphan_cbs_list; /* list of rcu_head structs */
/* orphaned by all CPUs in */
/* a given leaf rcu_node */
/* going offline. */
struct rcu_head **orphan_cbs_tail; /* And tail pointer. */
long orphan_qlen; /* Number of orphaned cbs. */
spinlock_t fqslock; /* Only one task forcing */
/* quiescent states. */
unsigned long jiffies_force_qs; /* Time at which to invoke */
@ -255,5 +290,30 @@ extern struct rcu_state rcu_preempt_state;
DECLARE_PER_CPU(struct rcu_data, rcu_preempt_data);
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
#endif /* #ifdef RCU_TREE_NONCORE */
#else /* #ifdef RCU_TREE_NONCORE */
/* Forward declarations for rcutree_plugin.h */
static inline void rcu_bootup_announce(void);
long rcu_batches_completed(void);
static void rcu_preempt_note_context_switch(int cpu);
static int rcu_preempted_readers(struct rcu_node *rnp);
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
static void rcu_print_task_stall(struct rcu_node *rnp);
#endif /* #ifdef CONFIG_RCU_CPU_STALL_DETECTOR */
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp);
#ifdef CONFIG_HOTPLUG_CPU
static void rcu_preempt_offline_tasks(struct rcu_state *rsp,
struct rcu_node *rnp,
struct rcu_data *rdp);
static void rcu_preempt_offline_cpu(int cpu);
#endif /* #ifdef CONFIG_HOTPLUG_CPU */
static void rcu_preempt_check_callbacks(int cpu);
static void rcu_preempt_process_callbacks(void);
void call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu));
static int rcu_preempt_pending(int cpu);
static int rcu_preempt_needs_cpu(int cpu);
static void __cpuinit rcu_preempt_init_percpu_data(int cpu);
static void rcu_preempt_send_cbs_to_orphanage(void);
static void __init __rcu_init_preempt(void);
#endif /* #else #ifdef RCU_TREE_NONCORE */

103
kernel/rcutree_plugin.h
View File

@ -150,6 +150,16 @@ void __rcu_read_lock(void)
}
EXPORT_SYMBOL_GPL(__rcu_read_lock);
/*
* Check for preempted RCU readers blocking the current grace period
* for the specified rcu_node structure. If the caller needs a reliable
* answer, it must hold the rcu_node's ->lock.
*/
static int rcu_preempted_readers(struct rcu_node *rnp)
{
return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]);
}
static void rcu_read_unlock_special(struct task_struct *t)
{
int empty;
@ -196,7 +206,7 @@ static void rcu_read_unlock_special(struct task_struct *t)
break;
spin_unlock(&rnp->lock); /* irqs remain disabled. */
}
empty = list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]);
empty = !rcu_preempted_readers(rnp);
list_del_init(&t->rcu_node_entry);
t->rcu_blocked_node = NULL;
@ -207,7 +217,7 @@ static void rcu_read_unlock_special(struct task_struct *t)
* drop rnp->lock and restore irq.
*/
if (!empty && rnp->qsmask == 0 &&
list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1])) {
!rcu_preempted_readers(rnp)) {
struct rcu_node *rnp_p;
if (rnp->parent == NULL) {
@ -257,12 +267,12 @@ static void rcu_print_task_stall(struct rcu_node *rnp)
{
unsigned long flags;
struct list_head *lp;
int phase = rnp->gpnum & 0x1;
int phase;
struct task_struct *t;
if (!list_empty(&rnp->blocked_tasks[phase])) {
if (rcu_preempted_readers(rnp)) {
spin_lock_irqsave(&rnp->lock, flags);
phase = rnp->gpnum & 0x1; /* re-read under lock. */
phase = rnp->gpnum & 0x1;
lp = &rnp->blocked_tasks[phase];
list_for_each_entry(t, lp, rcu_node_entry)
printk(" P%d", t->pid);
@ -281,20 +291,10 @@ static void rcu_print_task_stall(struct rcu_node *rnp)
*/
static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
{
WARN_ON_ONCE(!list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]));
WARN_ON_ONCE(rcu_preempted_readers(rnp));
WARN_ON_ONCE(rnp->qsmask);
}
/*
* Check for preempted RCU readers for the specified rcu_node structure.
* If the caller needs a reliable answer, it must hold the rcu_node's
* >lock.
*/
static int rcu_preempted_readers(struct rcu_node *rnp)
{
return !list_empty(&rnp->blocked_tasks[rnp->gpnum & 0x1]);
}
#ifdef CONFIG_HOTPLUG_CPU
/*
@ -410,6 +410,15 @@ static int rcu_preempt_needs_cpu(int cpu)
return !!per_cpu(rcu_preempt_data, cpu).nxtlist;
}
/**
* rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
*/
void rcu_barrier(void)
{
_rcu_barrier(&rcu_preempt_state, call_rcu);
}
EXPORT_SYMBOL_GPL(rcu_barrier);
/*
* Initialize preemptable RCU's per-CPU data.
*/
@ -418,6 +427,22 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu)
rcu_init_percpu_data(cpu, &rcu_preempt_state, 1);
}
/*
* Move preemptable RCU's callbacks to ->orphan_cbs_list.
*/
static void rcu_preempt_send_cbs_to_orphanage(void)
{
rcu_send_cbs_to_orphanage(&rcu_preempt_state);
}
/*
* Initialize preemptable RCU's state structures.
*/
static void __init __rcu_init_preempt(void)
{
RCU_INIT_FLAVOR(&rcu_preempt_state, rcu_preempt_data);
}
/*
* Check for a task exiting while in a preemptable-RCU read-side
* critical section, clean up if so. No need to issue warnings,
@ -461,6 +486,15 @@ static void rcu_preempt_note_context_switch(int cpu)
{
}
/*
* Because preemptable RCU does not exist, there are never any preempted
* RCU readers.
*/
static int rcu_preempted_readers(struct rcu_node *rnp)
{
return 0;
}
#ifdef CONFIG_RCU_CPU_STALL_DETECTOR
/*
@ -483,15 +517,6 @@ static void rcu_preempt_check_blocked_tasks(struct rcu_node *rnp)
WARN_ON_ONCE(rnp->qsmask);
}
/*
* Because preemptable RCU does not exist, there are never any preempted
* RCU readers.
*/
static int rcu_preempted_readers(struct rcu_node *rnp)
{
return 0;
}
#ifdef CONFIG_HOTPLUG_CPU
/*
@ -518,7 +543,7 @@ static void rcu_preempt_offline_cpu(int cpu)
* Because preemptable RCU does not exist, it never has any callbacks
* to check.
*/
void rcu_preempt_check_callbacks(int cpu)
static void rcu_preempt_check_callbacks(int cpu)
{
}
@ -526,7 +551,7 @@ void rcu_preempt_check_callbacks(int cpu)
* Because preemptable RCU does not exist, it never has any callbacks
* to process.
*/
void rcu_preempt_process_callbacks(void)
static void rcu_preempt_process_callbacks(void)
{
}
@ -555,6 +580,16 @@ static int rcu_preempt_needs_cpu(int cpu)
return 0;
}
/*
* Because preemptable RCU does not exist, rcu_barrier() is just
* another name for rcu_barrier_sched().
*/
void rcu_barrier(void)
{
rcu_barrier_sched();
}
EXPORT_SYMBOL_GPL(rcu_barrier);
/*
* Because preemptable RCU does not exist, there is no per-CPU
* data to initialize.
@ -563,4 +598,18 @@ static void __cpuinit rcu_preempt_init_percpu_data(int cpu)
{
}
/*
* Because there is no preemptable RCU, there are no callbacks to move.
*/
static void rcu_preempt_send_cbs_to_orphanage(void)
{
}
/*
* Because preemptable RCU does not exist, it need not be initialized.
*/
static void __init __rcu_init_preempt(void)
{
}
#endif /* #else #ifdef CONFIG_TREE_PREEMPT_RCU */

4
kernel/rcutree_trace.c
View File

@ -159,13 +159,13 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
struct rcu_node *rnp;
seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x "
"nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n",
"nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld\n",
rsp->completed, rsp->gpnum, rsp->signaled,
(long)(rsp->jiffies_force_qs - jiffies),
(int)(jiffies & 0xffff),
rsp->n_force_qs, rsp->n_force_qs_ngp,
rsp->n_force_qs - rsp->n_force_qs_ngp,
rsp->n_force_qs_lh);
rsp->n_force_qs_lh, rsp->orphan_qlen);
for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) {
if (rnp->level != level) {
seq_puts(m, "\n");