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Merge branches 'urgent.2012.10.27a', 'doc.2012.11.16a', 'fixes.2012.11.13a', 'srcu.2012.10.27a', 'stall.2012.11.13a', 'tracing.2012.11.08a' and 'idle.2012.10.24a' into HEAD

Browse Source 
urgent.2012.10.27a: Fix for RCU user-mode transition (already in -tip).

doc.2012.11.08a: Documentation updates, most notably codifying the
	memory-barrier guarantees inherent to grace periods.

fixes.2012.11.13a: Miscellaneous fixes.

srcu.2012.10.27a: Allow statically allocated and initialized srcu_struct
	structures (courtesy of Lai Jiangshan).

stall.2012.11.13a: Add more diagnostic information to RCU CPU stall
	warnings, also decrease from 60 seconds to 21 seconds.

hotplug.2012.11.08a: Minor updates to CPU hotplug handling.

tracing.2012.11.08a: Improved debugfs tracing, courtesy of Michael Wang.

idle.2012.10.24a: Updates to RCU idle/adaptive-idle handling, including
	a boot parameter that maps normal grace periods to expedited.

Resolved conflict in kernel/rcutree.c due to side-by-side change.
This commit is contained in:
Paul E. McKenney
2012-11-16 09:59:58 -08:00
parent 2c5594df34 d484a21513 351573a86d cda4dc8130 c896054f75 7bd8f2a74b af71befa28
commit aac1cda34b
26 changed files with 786 additions and 496 deletions
Download Patch File Download Diff File Expand all files Collapse all files

18
kernel/ksysfs.c
View File

@@ -141,6 +141,23 @@ static ssize_t fscaps_show(struct kobject *kobj,
}
KERNEL_ATTR_RO(fscaps);
int rcu_expedited;
static ssize_t rcu_expedited_show(struct kobject *kobj,
struct kobj_attribute *attr, char *buf)
{
return sprintf(buf, "%d\n", rcu_expedited);
}
static ssize_t rcu_expedited_store(struct kobject *kobj,
struct kobj_attribute *attr,
const char *buf, size_t count)
{
if (kstrtoint(buf, 0, &rcu_expedited))
return -EINVAL;
return count;
}
KERNEL_ATTR_RW(rcu_expedited);
/*
* Make /sys/kernel/notes give the raw contents of our kernel .notes section.
*/
@@ -182,6 +199,7 @@ static struct attribute * kernel_attrs[] = {
&kexec_crash_size_attr.attr,
&vmcoreinfo_attr.attr,
#endif
&rcu_expedited_attr.attr,
NULL
};

2
kernel/rcu.h
View File

@@ -109,4 +109,6 @@ static inline bool __rcu_reclaim(char *rn, struct rcu_head *head)
}
}
extern int rcu_expedited;
#endif /* __LINUX_RCU_H */

3
kernel/rcupdate.c
View File

@@ -46,12 +46,15 @@
#include <linux/export.h>
#include <linux/hardirq.h>
#include <linux/delay.h>
#include <linux/module.h>
#define CREATE_TRACE_POINTS
#include <trace/events/rcu.h>
#include "rcu.h"
module_param(rcu_expedited, int, 0);
#ifdef CONFIG_PREEMPT_RCU
/*

2
kernel/rcutiny.c
View File

@@ -195,7 +195,7 @@ EXPORT_SYMBOL(rcu_is_cpu_idle);
*/
int rcu_is_cpu_rrupt_from_idle(void)
{
return rcu_dynticks_nesting <= 0;
return rcu_dynticks_nesting <= 1;
}
/*

5
kernel/rcutiny_plugin.h
View File

@@ -706,7 +706,10 @@ void synchronize_rcu(void)
return;
/* Once we get past the fastpath checks, same code as rcu_barrier(). */
rcu_barrier();
if (rcu_expedited)
synchronize_rcu_expedited();
else
rcu_barrier();
}
EXPORT_SYMBOL_GPL(synchronize_rcu);

54
kernel/rcutorture.c
View File

@@ -339,7 +339,6 @@ rcu_stutter_wait(char *title)
struct rcu_torture_ops {
void (*init)(void);
void (*cleanup)(void);
int (*readlock)(void);
void (*read_delay)(struct rcu_random_state *rrsp);
void (*readunlock)(int idx);
@@ -431,7 +430,6 @@ static void rcu_torture_deferred_free(struct rcu_torture *p)
static struct rcu_torture_ops rcu_ops = {
.init = NULL,
.cleanup = NULL,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay,
.readunlock = rcu_torture_read_unlock,
@@ -475,7 +473,6 @@ static void rcu_sync_torture_init(void)
static struct rcu_torture_ops rcu_sync_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay,
.readunlock = rcu_torture_read_unlock,
@@ -493,7 +490,6 @@ static struct rcu_torture_ops rcu_sync_ops = {
static struct rcu_torture_ops rcu_expedited_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_torture_read_unlock,
@@ -536,7 +532,6 @@ static void rcu_bh_torture_deferred_free(struct rcu_torture *p)
static struct rcu_torture_ops rcu_bh_ops = {
.init = NULL,
.cleanup = NULL,
.readlock = rcu_bh_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_bh_torture_read_unlock,
@@ -553,7 +548,6 @@ static struct rcu_torture_ops rcu_bh_ops = {
static struct rcu_torture_ops rcu_bh_sync_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_bh_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_bh_torture_read_unlock,
@@ -570,7 +564,6 @@ static struct rcu_torture_ops rcu_bh_sync_ops = {
static struct rcu_torture_ops rcu_bh_expedited_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = rcu_bh_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = rcu_bh_torture_read_unlock,
@@ -589,19 +582,7 @@ static struct rcu_torture_ops rcu_bh_expedited_ops = {
* Definitions for srcu torture testing.
*/
static struct srcu_struct srcu_ctl;
static void srcu_torture_init(void)
{
init_srcu_struct(&srcu_ctl);
rcu_sync_torture_init();
}
static void srcu_torture_cleanup(void)
{
synchronize_srcu(&srcu_ctl);
cleanup_srcu_struct(&srcu_ctl);
}
DEFINE_STATIC_SRCU(srcu_ctl);
static int srcu_torture_read_lock(void) __acquires(&srcu_ctl)
{
@@ -672,8 +653,7 @@ static int srcu_torture_stats(char *page)
}
static struct rcu_torture_ops srcu_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.init = rcu_sync_torture_init,
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
@@ -687,8 +667,7 @@ static struct rcu_torture_ops srcu_ops = {
};
static struct rcu_torture_ops srcu_sync_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.init = rcu_sync_torture_init,
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
@@ -712,8 +691,7 @@ static void srcu_torture_read_unlock_raw(int idx) __releases(&srcu_ctl)
}
static struct rcu_torture_ops srcu_raw_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.init = rcu_sync_torture_init,
.readlock = srcu_torture_read_lock_raw,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock_raw,
@@ -727,8 +705,7 @@ static struct rcu_torture_ops srcu_raw_ops = {
};
static struct rcu_torture_ops srcu_raw_sync_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.init = rcu_sync_torture_init,
.readlock = srcu_torture_read_lock_raw,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock_raw,
@@ -747,8 +724,7 @@ static void srcu_torture_synchronize_expedited(void)
}
static struct rcu_torture_ops srcu_expedited_ops = {
.init = srcu_torture_init,
.cleanup = srcu_torture_cleanup,
.init = rcu_sync_torture_init,
.readlock = srcu_torture_read_lock,
.read_delay = srcu_read_delay,
.readunlock = srcu_torture_read_unlock,
@@ -783,7 +759,6 @@ static void rcu_sched_torture_deferred_free(struct rcu_torture *p)
static struct rcu_torture_ops sched_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = sched_torture_read_unlock,
@@ -799,7 +774,6 @@ static struct rcu_torture_ops sched_ops = {
static struct rcu_torture_ops sched_sync_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = sched_torture_read_unlock,
@@ -814,7 +788,6 @@ static struct rcu_torture_ops sched_sync_ops = {
static struct rcu_torture_ops sched_expedited_ops = {
.init = rcu_sync_torture_init,
.cleanup = NULL,
.readlock = sched_torture_read_lock,
.read_delay = rcu_read_delay, /* just reuse rcu's version. */
.readunlock = sched_torture_read_unlock,
@@ -1396,12 +1369,16 @@ rcu_torture_print_module_parms(struct rcu_torture_ops *cur_ops, char *tag)
"fqs_duration=%d fqs_holdoff=%d fqs_stutter=%d "
"test_boost=%d/%d test_boost_interval=%d "
"test_boost_duration=%d shutdown_secs=%d "
"stall_cpu=%d stall_cpu_holdoff=%d "
"n_barrier_cbs=%d "
"onoff_interval=%d onoff_holdoff=%d\n",
torture_type, tag, nrealreaders, nfakewriters,
stat_interval, verbose, test_no_idle_hz, shuffle_interval,
stutter, irqreader, fqs_duration, fqs_holdoff, fqs_stutter,
test_boost, cur_ops->can_boost,
test_boost_interval, test_boost_duration, shutdown_secs,
stall_cpu, stall_cpu_holdoff,
n_barrier_cbs,
onoff_interval, onoff_holdoff);
}
@@ -1502,6 +1479,7 @@ rcu_torture_onoff(void *arg)
unsigned long delta;
int maxcpu = -1;
DEFINE_RCU_RANDOM(rand);
int ret;
unsigned long starttime;
VERBOSE_PRINTK_STRING("rcu_torture_onoff task started");
@@ -1522,7 +1500,13 @@ rcu_torture_onoff(void *arg)
torture_type, cpu);
starttime = jiffies;
n_offline_attempts++;
if (cpu_down(cpu) == 0) {
ret = cpu_down(cpu);
if (ret) {
if (verbose)
pr_alert("%s" TORTURE_FLAG
"rcu_torture_onoff task: offline %d failed: errno %d\n",
torture_type, cpu, ret);
} else {
if (verbose)
pr_alert("%s" TORTURE_FLAG
"rcu_torture_onoff task: offlined %d\n",
@@ -1936,8 +1920,6 @@ rcu_torture_cleanup(void)
rcu_torture_stats_print(); /* -After- the stats thread is stopped! */
if (cur_ops->cleanup)
cur_ops->cleanup();
if (atomic_read(&n_rcu_torture_error) || n_rcu_torture_barrier_error)
rcu_torture_print_module_parms(cur_ops, "End of test: FAILURE");
else if (n_online_successes != n_online_attempts ||

222
kernel/rcutree.c
View File

@@ -68,9 +68,9 @@ static struct lock_class_key rcu_fqs_class[RCU_NUM_LVLS];
.level = { &sname##_state.node[0] }, \
.call = cr, \
.fqs_state = RCU_GP_IDLE, \
.gpnum = -300, \
.completed = -300, \
.onofflock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.onofflock), \
.gpnum = 0UL - 300UL, \
.completed = 0UL - 300UL, \
.orphan_lock = __RAW_SPIN_LOCK_UNLOCKED(&sname##_state.orphan_lock), \
.orphan_nxttail = &sname##_state.orphan_nxtlist, \
.orphan_donetail = &sname##_state.orphan_donelist, \
.barrier_mutex = __MUTEX_INITIALIZER(sname##_state.barrier_mutex), \
@@ -212,13 +212,13 @@ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
#endif
};
static int blimit = 10; /* Maximum callbacks per rcu_do_batch. */
static int qhimark = 10000; /* If this many pending, ignore blimit. */
static int qlowmark = 100; /* Once only this many pending, use blimit. */
static long blimit = 10; /* Maximum callbacks per rcu_do_batch. */
static long qhimark = 10000; /* If this many pending, ignore blimit. */
static long qlowmark = 100; /* Once only this many pending, use blimit. */
module_param(blimit, int, 0444);
module_param(qhimark, int, 0444);
module_param(qlowmark, int, 0444);
module_param(blimit, long, 0444);
module_param(qhimark, long, 0444);
module_param(qlowmark, long, 0444);
int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
@@ -313,7 +313,7 @@ static int
cpu_needs_another_gp(struct rcu_state *rsp, struct rcu_data *rdp)
{
return *rdp->nxttail[RCU_DONE_TAIL +
ACCESS_ONCE(rsp->completed) != rdp->completed] &&
(ACCESS_ONCE(rsp->completed) != rdp->completed)] &&
!rcu_gp_in_progress(rsp);
}
@@ -873,6 +873,29 @@ static void record_gp_stall_check_time(struct rcu_state *rsp)
rsp->jiffies_stall = jiffies + jiffies_till_stall_check();
}
/*
* Dump stacks of all tasks running on stalled CPUs. This is a fallback
* for architectures that do not implement trigger_all_cpu_backtrace().
* The NMI-triggered stack traces are more accurate because they are
* printed by the target CPU.
*/
static void rcu_dump_cpu_stacks(struct rcu_state *rsp)
{
int cpu;
unsigned long flags;
struct rcu_node *rnp;
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave(&rnp->lock, flags);
if (rnp->qsmask != 0) {
for (cpu = 0; cpu <= rnp->grphi - rnp->grplo; cpu++)
if (rnp->qsmask & (1UL << cpu))
dump_cpu_task(rnp->grplo + cpu);
}
raw_spin_unlock_irqrestore(&rnp->lock, flags);
}
}
static void print_other_cpu_stall(struct rcu_state *rsp)
{
int cpu;
@@ -880,6 +903,7 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
unsigned long flags;
int ndetected = 0;
struct rcu_node *rnp = rcu_get_root(rsp);
long totqlen = 0;
/* Only let one CPU complain about others per time interval. */
@@ -924,12 +948,15 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
raw_spin_unlock_irqrestore(&rnp->lock, flags);
print_cpu_stall_info_end();
printk(KERN_CONT "(detected by %d, t=%ld jiffies)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start));
for_each_possible_cpu(cpu)
totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen;
pr_cont("(detected by %d, t=%ld jiffies, g=%lu, c=%lu, q=%lu)\n",
smp_processor_id(), (long)(jiffies - rsp->gp_start),
rsp->gpnum, rsp->completed, totqlen);
if (ndetected == 0)
printk(KERN_ERR "INFO: Stall ended before state dump start\n");
else if (!trigger_all_cpu_backtrace())
dump_stack();
rcu_dump_cpu_stacks(rsp);
/* Complain about tasks blocking the grace period. */
@@ -940,8 +967,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp)
static void print_cpu_stall(struct rcu_state *rsp)
{
int cpu;
unsigned long flags;
struct rcu_node *rnp = rcu_get_root(rsp);
long totqlen = 0;
/*
* OK, time to rat on ourselves...
@@ -952,7 +981,10 @@ static void print_cpu_stall(struct rcu_state *rsp)
print_cpu_stall_info_begin();
print_cpu_stall_info(rsp, smp_processor_id());
print_cpu_stall_info_end();
printk(KERN_CONT " (t=%lu jiffies)\n", jiffies - rsp->gp_start);
for_each_possible_cpu(cpu)
totqlen += per_cpu_ptr(rsp->rda, cpu)->qlen;
pr_cont(" (t=%lu jiffies g=%lu c=%lu q=%lu)\n",
jiffies - rsp->gp_start, rsp->gpnum, rsp->completed, totqlen);
if (!trigger_all_cpu_backtrace())
dump_stack();
@@ -1404,15 +1436,37 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags)
!cpu_needs_another_gp(rsp, rdp)) {
/*
* Either we have not yet spawned the grace-period
* task or this CPU does not need another grace period.
* task, this CPU does not need another grace period,
* or a grace period is already in progress.
* Either way, don't start a new grace period.
*/
raw_spin_unlock_irqrestore(&rnp->lock, flags);
return;
}
/*
* Because there is no grace period in progress right now,
* any callbacks we have up to this point will be satisfied
* by the next grace period. So promote all callbacks to be
* handled after the end of the next grace period. If the
* CPU is not yet aware of the end of the previous grace period,
* we need to allow for the callback advancement that will
* occur when it does become aware. Deadlock prevents us from
* making it aware at this point: We cannot acquire a leaf
* rcu_node ->lock while holding the root rcu_node ->lock.
*/
rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
if (rdp->completed == rsp->completed)
rdp->nxttail[RCU_WAIT_TAIL] = rdp->nxttail[RCU_NEXT_TAIL];
rsp->gp_flags = RCU_GP_FLAG_INIT;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
raw_spin_unlock(&rnp->lock); /* Interrupts remain disabled. */
/* Ensure that CPU is aware of completion of last grace period. */
rcu_process_gp_end(rsp, rdp);
local_irq_restore(flags);
/* Wake up rcu_gp_kthread() to start the grace period. */
wake_up(&rsp->gp_wq);
}
@@ -1573,7 +1627,7 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp)
/*
* Send the specified CPU's RCU callbacks to the orphanage. The
* specified CPU must be offline, and the caller must hold the
* ->onofflock.
* ->orphan_lock.
*/
static void
rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
@@ -1581,8 +1635,8 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
{
/*
* Orphan the callbacks. First adjust the counts. This is safe
* because ->onofflock excludes _rcu_barrier()'s adoption of
* the callbacks, thus no memory barrier is required.
* because _rcu_barrier() excludes CPU-hotplug operations, so it
* cannot be running now. Thus no memory barrier is required.
*/
if (rdp->nxtlist != NULL) {
rsp->qlen_lazy += rdp->qlen_lazy;
@@ -1623,7 +1677,7 @@ rcu_send_cbs_to_orphanage(int cpu, struct rcu_state *rsp,
/*
* Adopt the RCU callbacks from the specified rcu_state structure's
* orphanage. The caller must hold the ->onofflock.
* orphanage. The caller must hold the ->orphan_lock.
*/
static void rcu_adopt_orphan_cbs(struct rcu_state *rsp)
{
@@ -1702,7 +1756,7 @@ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp)
/* Exclude any attempts to start a new grace period. */
mutex_lock(&rsp->onoff_mutex);
raw_spin_lock_irqsave(&rsp->onofflock, flags);
raw_spin_lock_irqsave(&rsp->orphan_lock, flags);
/* Orphan the dead CPU's callbacks, and adopt them if appropriate. */
rcu_send_cbs_to_orphanage(cpu, rsp, rnp, rdp);
@@ -1729,10 +1783,10 @@ static void rcu_cleanup_dead_cpu(int cpu, struct rcu_state *rsp)
/*
* We still hold the leaf rcu_node structure lock here, and
* irqs are still disabled. The reason for this subterfuge is
* because invoking rcu_report_unblock_qs_rnp() with ->onofflock
* because invoking rcu_report_unblock_qs_rnp() with ->orphan_lock
* held leads to deadlock.
*/
raw_spin_unlock(&rsp->onofflock); /* irqs remain disabled. */
raw_spin_unlock(&rsp->orphan_lock); /* irqs remain disabled. */
rnp = rdp->mynode;
if (need_report & RCU_OFL_TASKS_NORM_GP)
rcu_report_unblock_qs_rnp(rnp, flags);
@@ -1769,7 +1823,8 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp)
{
unsigned long flags;
struct rcu_head *next, *list, **tail;
int bl, count, count_lazy, i;
long bl, count, count_lazy;
int i;
/* If no callbacks are ready, just return.*/
if (!cpu_has_callbacks_ready_to_invoke(rdp)) {
@@ -2205,10 +2260,28 @@ static inline int rcu_blocking_is_gp(void)
* rcu_read_lock_sched().
*
* This means that all preempt_disable code sequences, including NMI and
* hardware-interrupt handlers, in progress on entry will have completed
* before this primitive returns. However, this does not guarantee that
* softirq handlers will have completed, since in some kernels, these
* handlers can run in process context, and can block.
* non-threaded hardware-interrupt handlers, in progress on entry will
* have completed before this primitive returns. However, this does not
* guarantee that softirq handlers will have completed, since in some
* kernels, these handlers can run in process context, and can block.
*
* Note that this guarantee implies further memory-ordering guarantees.
* On systems with more than one CPU, when synchronize_sched() returns,
* each CPU is guaranteed to have executed a full memory barrier since the
* end of its last RCU-sched read-side critical section whose beginning
* preceded the call to synchronize_sched(). In addition, each CPU having
* an RCU read-side critical section that extends beyond the return from
* synchronize_sched() is guaranteed to have executed a full memory barrier
* after the beginning of synchronize_sched() and before the beginning of
* that RCU read-side critical section. Note that these guarantees include
* CPUs that are offline, idle, or executing in user mode, as well as CPUs
* that are executing in the kernel.
*
* Furthermore, if CPU A invoked synchronize_sched(), which returned
* to its caller on CPU B, then both CPU A and CPU B are guaranteed
* to have executed a full memory barrier during the execution of
* synchronize_sched() -- even if CPU A and CPU B are the same CPU (but
* again only if the system has more than one CPU).
*
* This primitive provides the guarantees made by the (now removed)
* synchronize_kernel() API. In contrast, synchronize_rcu() only
@@ -2224,7 +2297,10 @@ void synchronize_sched(void)
"Illegal synchronize_sched() in RCU-sched read-side critical section");
if (rcu_blocking_is_gp())
return;
wait_rcu_gp(call_rcu_sched);
if (rcu_expedited)
synchronize_sched_expedited();
else
wait_rcu_gp(call_rcu_sched);
}
EXPORT_SYMBOL_GPL(synchronize_sched);
@@ -2236,6 +2312,9 @@ EXPORT_SYMBOL_GPL(synchronize_sched);
* read-side critical sections have completed. RCU read-side critical
* sections are delimited by rcu_read_lock_bh() and rcu_read_unlock_bh(),
* and may be nested.
*
* See the description of synchronize_sched() for more detailed information
* on memory ordering guarantees.
*/
void synchronize_rcu_bh(void)
{
@@ -2245,13 +2324,13 @@ void synchronize_rcu_bh(void)
"Illegal synchronize_rcu_bh() in RCU-bh read-side critical section");
if (rcu_blocking_is_gp())
return;
wait_rcu_gp(call_rcu_bh);
if (rcu_expedited)
synchronize_rcu_bh_expedited();
else
wait_rcu_gp(call_rcu_bh);
}
EXPORT_SYMBOL_GPL(synchronize_rcu_bh);
static atomic_t sync_sched_expedited_started = ATOMIC_INIT(0);
static atomic_t sync_sched_expedited_done = ATOMIC_INIT(0);
static int synchronize_sched_expedited_cpu_stop(void *data)
{
/*
@@ -2308,10 +2387,32 @@ static int synchronize_sched_expedited_cpu_stop(void *data)
*/
void synchronize_sched_expedited(void)
{
int firstsnap, s, snap, trycount = 0;
long firstsnap, s, snap;
int trycount = 0;
struct rcu_state *rsp = &rcu_sched_state;
/* Note that atomic_inc_return() implies full memory barrier. */
firstsnap = snap = atomic_inc_return(&sync_sched_expedited_started);
/*
* If we are in danger of counter wrap, just do synchronize_sched().
* By allowing sync_sched_expedited_started to advance no more than
* ULONG_MAX/8 ahead of sync_sched_expedited_done, we are ensuring
* that more than 3.5 billion CPUs would be required to force a
* counter wrap on a 32-bit system. Quite a few more CPUs would of
* course be required on a 64-bit system.
*/
if (ULONG_CMP_GE((ulong)atomic_long_read(&rsp->expedited_start),
(ulong)atomic_long_read(&rsp->expedited_done) +
ULONG_MAX / 8)) {
synchronize_sched();
atomic_long_inc(&rsp->expedited_wrap);
return;
}
/*
* Take a ticket. Note that atomic_inc_return() implies a
* full memory barrier.
*/
snap = atomic_long_inc_return(&rsp->expedited_start);
firstsnap = snap;
get_online_cpus();
WARN_ON_ONCE(cpu_is_offline(raw_smp_processor_id()));
@@ -2323,48 +2424,65 @@ void synchronize_sched_expedited(void)
synchronize_sched_expedited_cpu_stop,
NULL) == -EAGAIN) {
put_online_cpus();
atomic_long_inc(&rsp->expedited_tryfail);
/* Check to see if someone else did our work for us. */
s = atomic_long_read(&rsp->expedited_done);
if (ULONG_CMP_GE((ulong)s, (ulong)firstsnap)) {
/* ensure test happens before caller kfree */
smp_mb__before_atomic_inc(); /* ^^^ */
atomic_long_inc(&rsp->expedited_workdone1);
return;
}
/* No joy, try again later. Or just synchronize_sched(). */
if (trycount++ < 10) {
udelay(trycount * num_online_cpus());
} else {
synchronize_sched();
wait_rcu_gp(call_rcu_sched);
atomic_long_inc(&rsp->expedited_normal);
return;
}
/* Check to see if someone else did our work for us. */
s = atomic_read(&sync_sched_expedited_done);
if (UINT_CMP_GE((unsigned)s, (unsigned)firstsnap)) {
smp_mb(); /* ensure test happens before caller kfree */
/* Recheck to see if someone else did our work for us. */
s = atomic_long_read(&rsp->expedited_done);
if (ULONG_CMP_GE((ulong)s, (ulong)firstsnap)) {
/* ensure test happens before caller kfree */
smp_mb__before_atomic_inc(); /* ^^^ */
atomic_long_inc(&rsp->expedited_workdone2);
return;
}
/*
* Refetching sync_sched_expedited_started allows later
* callers to piggyback on our grace period. We subtract
* 1 to get the same token that the last incrementer got.
* We retry after they started, so our grace period works
* for them, and they started after our first try, so their
* grace period works for us.
* callers to piggyback on our grace period. We retry
* after they started, so our grace period works for them,
* and they started after our first try, so their grace
* period works for us.
*/
get_online_cpus();
snap = atomic_read(&sync_sched_expedited_started);
snap = atomic_long_read(&rsp->expedited_start);
smp_mb(); /* ensure read is before try_stop_cpus(). */
}
atomic_long_inc(&rsp->expedited_stoppedcpus);
/*
* Everyone up to our most recent fetch is covered by our grace
* period. Update the counter, but only if our work is still
* relevant -- which it won't be if someone who started later
* than we did beat us to the punch.
* than we did already did their update.
*/
do {
s = atomic_read(&sync_sched_expedited_done);
if (UINT_CMP_GE((unsigned)s, (unsigned)snap)) {
smp_mb(); /* ensure test happens before caller kfree */
atomic_long_inc(&rsp->expedited_done_tries);
s = atomic_long_read(&rsp->expedited_done);
if (ULONG_CMP_GE((ulong)s, (ulong)snap)) {
/* ensure test happens before caller kfree */
smp_mb__before_atomic_inc(); /* ^^^ */
atomic_long_inc(&rsp->expedited_done_lost);
break;
}
} while (atomic_cmpxchg(&sync_sched_expedited_done, s, snap) != s);
} while (atomic_long_cmpxchg(&rsp->expedited_done, s, snap) != s);
atomic_long_inc(&rsp->expedited_done_exit);
put_online_cpus();
}

19
kernel/rcutree.h
View File

@@ -383,9 +383,8 @@ struct rcu_state {
/* End of fields guarded by root rcu_node's lock. */
raw_spinlock_t onofflock ____cacheline_internodealigned_in_smp;
/* exclude on/offline and */
/* starting new GP. */
raw_spinlock_t orphan_lock ____cacheline_internodealigned_in_smp;
/* Protect following fields. */
struct rcu_head *orphan_nxtlist; /* Orphaned callbacks that */
/* need a grace period. */
struct rcu_head **orphan_nxttail; /* Tail of above. */
@@ -394,7 +393,7 @@ struct rcu_state {
struct rcu_head **orphan_donetail; /* Tail of above. */
long qlen_lazy; /* Number of lazy callbacks. */
long qlen; /* Total number of callbacks. */
/* End of fields guarded by onofflock. */
/* End of fields guarded by orphan_lock. */
struct mutex onoff_mutex; /* Coordinate hotplug & GPs. */
@@ -405,6 +404,18 @@ struct rcu_state {
/* _rcu_barrier(). */
/* End of fields guarded by barrier_mutex. */
atomic_long_t expedited_start; /* Starting ticket. */
atomic_long_t expedited_done; /* Done ticket. */
atomic_long_t expedited_wrap; /* # near-wrap incidents. */
atomic_long_t expedited_tryfail; /* # acquisition failures. */
atomic_long_t expedited_workdone1; /* # done by others #1. */
atomic_long_t expedited_workdone2; /* # done by others #2. */
atomic_long_t expedited_normal; /* # fallbacks to normal. */
atomic_long_t expedited_stoppedcpus; /* # successful stop_cpus. */
atomic_long_t expedited_done_tries; /* # tries to update _done. */
atomic_long_t expedited_done_lost; /* # times beaten to _done. */
atomic_long_t expedited_done_exit; /* # times exited _done loop. */
unsigned long jiffies_force_qs; /* Time at which to invoke */
/* force_quiescent_state(). */
unsigned long n_force_qs; /* Number of calls to */

18
kernel/rcutree_plugin.h
View File

@@ -670,6 +670,9 @@ EXPORT_SYMBOL_GPL(kfree_call_rcu);
* concurrently with new RCU read-side critical sections that began while
* synchronize_rcu() was waiting. RCU read-side critical sections are
* delimited by rcu_read_lock() and rcu_read_unlock(), and may be nested.
*
* See the description of synchronize_sched() for more detailed information
* on memory ordering guarantees.
*/
void synchronize_rcu(void)
{
@@ -679,7 +682,10 @@ void synchronize_rcu(void)
"Illegal synchronize_rcu() in RCU read-side critical section");
if (!rcu_scheduler_active)
return;
wait_rcu_gp(call_rcu);
if (rcu_expedited)
synchronize_rcu_expedited();
else
wait_rcu_gp(call_rcu);
}
EXPORT_SYMBOL_GPL(synchronize_rcu);
@@ -757,7 +763,8 @@ static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
* grace period for the specified rcu_node structure. If there are no such
* tasks, report it up the rcu_node hierarchy.
*
* Caller must hold sync_rcu_preempt_exp_mutex and rsp->onofflock.
* Caller must hold sync_rcu_preempt_exp_mutex and must exclude
* CPU hotplug operations.
*/
static void
sync_rcu_preempt_exp_init(struct rcu_state *rsp, struct rcu_node *rnp)
@@ -831,7 +838,7 @@ void synchronize_rcu_expedited(void)
udelay(trycount * num_online_cpus());
} else {
put_online_cpus();
synchronize_rcu();
wait_rcu_gp(call_rcu);
return;
}
}
@@ -875,6 +882,11 @@ EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
/**
* rcu_barrier - Wait until all in-flight call_rcu() callbacks complete.
*
* Note that this primitive does not necessarily wait for an RCU grace period
* to complete. For example, if there are no RCU callbacks queued anywhere
* in the system, then rcu_barrier() is within its rights to return
* immediately, without waiting for anything, much less an RCU grace period.
*/
void rcu_barrier(void)
{

312
kernel/rcutree_trace.c
View File

@@ -46,29 +46,58 @@
#define RCU_TREE_NONCORE
#include "rcutree.h"
static int show_rcubarrier(struct seq_file *m, void *unused)
{
struct rcu_state *rsp;
#define ulong2long(a) (*(long *)(&(a)))
for_each_rcu_flavor(rsp)
seq_printf(m, "%s: bcc: %d nbd: %lu\n",
rsp->name,
atomic_read(&rsp->barrier_cpu_count),
rsp->n_barrier_done);
static int r_open(struct inode *inode, struct file *file,
const struct seq_operations *op)
{
int ret = seq_open(file, op);
if (!ret) {
struct seq_file *m = (struct seq_file *)file->private_data;
m->private = inode->i_private;
}
return ret;
}
static void *r_start(struct seq_file *m, loff_t *pos)
{
struct rcu_state *rsp = (struct rcu_state *)m->private;
*pos = cpumask_next(*pos - 1, cpu_possible_mask);
if ((*pos) < nr_cpu_ids)
return per_cpu_ptr(rsp->rda, *pos);
return NULL;
}
static void *r_next(struct seq_file *m, void *v, loff_t *pos)
{
(*pos)++;
return r_start(m, pos);
}
static void r_stop(struct seq_file *m, void *v)
{
}
static int show_rcubarrier(struct seq_file *m, void *v)
{
struct rcu_state *rsp = (struct rcu_state *)m->private;
seq_printf(m, "bcc: %d nbd: %lu\n",
atomic_read(&rsp->barrier_cpu_count),
rsp->n_barrier_done);
return 0;
}
static int rcubarrier_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcubarrier, NULL);
return single_open(file, show_rcubarrier, inode->i_private);
}
static const struct file_operations rcubarrier_fops = {
.owner = THIS_MODULE,
.open = rcubarrier_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.llseek = no_llseek,
.release = seq_release,
};
#ifdef CONFIG_RCU_BOOST
@@ -86,10 +115,10 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%3d%cc=%lu g=%lu pq=%d qp=%d",
seq_printf(m, "%3d%cc=%ld g=%ld pq=%d qp=%d",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? '!' : ' ',
rdp->completed, rdp->gpnum,
ulong2long(rdp->completed), ulong2long(rdp->gpnum),
rdp->passed_quiesce, rdp->qs_pending);
seq_printf(m, " dt=%d/%llx/%d df=%lu",
atomic_read(&rdp->dynticks->dynticks),
@@ -118,97 +147,62 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
}
static int show_rcudata(struct seq_file *m, void *unused)
static int show_rcudata(struct seq_file *m, void *v)
{
int cpu;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) {
seq_printf(m, "%s:\n", rsp->name);
for_each_possible_cpu(cpu)
print_one_rcu_data(m, per_cpu_ptr(rsp->rda, cpu));
}
print_one_rcu_data(m, (struct rcu_data *)v);
return 0;
}
static const struct seq_operations rcudate_op = {
.start = r_start,
.next = r_next,
.stop = r_stop,
.show = show_rcudata,
};
static int rcudata_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcudata, NULL);
return r_open(inode, file, &rcudate_op);
}
static const struct file_operations rcudata_fops = {
.owner = THIS_MODULE,
.open = rcudata_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.llseek = no_llseek,
.release = seq_release,
};
static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
static int show_rcuexp(struct seq_file *m, void *v)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%d,%s,%lu,%lu,%d,%d",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? "\"N\"" : "\"Y\"",
rdp->completed, rdp->gpnum,
rdp->passed_quiesce, rdp->qs_pending);
seq_printf(m, ",%d,%llx,%d,%lu",
atomic_read(&rdp->dynticks->dynticks),
rdp->dynticks->dynticks_nesting,
rdp->dynticks->dynticks_nmi_nesting,
rdp->dynticks_fqs);
seq_printf(m, ",%lu", rdp->offline_fqs);
seq_printf(m, ",%ld,%ld,\"%c%c%c%c\"", rdp->qlen_lazy, rdp->qlen,
".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
rdp->nxttail[RCU_NEXT_TAIL]],
".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
rdp->nxttail[RCU_NEXT_READY_TAIL]],
".W"[rdp->nxttail[RCU_DONE_TAIL] !=
rdp->nxttail[RCU_WAIT_TAIL]],
".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]]);
#ifdef CONFIG_RCU_BOOST
seq_printf(m, ",%d,\"%c\"",
per_cpu(rcu_cpu_has_work, rdp->cpu),
convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
rdp->cpu)));
#endif /* #ifdef CONFIG_RCU_BOOST */
seq_printf(m, ",%ld", rdp->blimit);
seq_printf(m, ",%lu,%lu,%lu\n",
rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
}
struct rcu_state *rsp = (struct rcu_state *)m->private;
static int show_rcudata_csv(struct seq_file *m, void *unused)
{
int cpu;
struct rcu_state *rsp;
seq_puts(m, "\"CPU\",\"Online?\",\"c\",\"g\",\"pq\",\"pq\",");
seq_puts(m, "\"dt\",\"dt nesting\",\"dt NMI nesting\",\"df\",");
seq_puts(m, "\"of\",\"qll\",\"ql\",\"qs\"");
#ifdef CONFIG_RCU_BOOST
seq_puts(m, "\"kt\",\"ktl\"");
#endif /* #ifdef CONFIG_RCU_BOOST */
seq_puts(m, ",\"b\",\"ci\",\"co\",\"ca\"\n");
for_each_rcu_flavor(rsp) {
seq_printf(m, "\"%s:\"\n", rsp->name);
for_each_possible_cpu(cpu)
print_one_rcu_data_csv(m, per_cpu_ptr(rsp->rda, cpu));
}
seq_printf(m, "s=%lu d=%lu w=%lu tf=%lu wd1=%lu wd2=%lu n=%lu sc=%lu dt=%lu dl=%lu dx=%lu\n",
atomic_long_read(&rsp->expedited_start),
atomic_long_read(&rsp->expedited_done),
atomic_long_read(&rsp->expedited_wrap),
atomic_long_read(&rsp->expedited_tryfail),
atomic_long_read(&rsp->expedited_workdone1),
atomic_long_read(&rsp->expedited_workdone2),
atomic_long_read(&rsp->expedited_normal),
atomic_long_read(&rsp->expedited_stoppedcpus),
atomic_long_read(&rsp->expedited_done_tries),
atomic_long_read(&rsp->expedited_done_lost),
atomic_long_read(&rsp->expedited_done_exit));
return 0;
}
static int rcudata_csv_open(struct inode *inode, struct file *file)
static int rcuexp_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcudata_csv, NULL);
return single_open(file, show_rcuexp, inode->i_private);
}
static const struct file_operations rcudata_csv_fops = {
static const struct file_operations rcuexp_fops = {
.owner = THIS_MODULE,
.open = rcudata_csv_open,
.open = rcuexp_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.llseek = no_llseek,
.release = seq_release,
};
#ifdef CONFIG_RCU_BOOST
@@ -254,27 +248,11 @@ static const struct file_operations rcu_node_boost_fops = {
.owner = THIS_MODULE,
.open = rcu_node_boost_open,
.read = seq_read,
.llseek = seq_lseek,
.llseek = no_llseek,
.release = single_release,
};
/*
* Create the rcuboost debugfs entry. Standard error return.
*/
static int rcu_boost_trace_create_file(struct dentry *rcudir)
{
return !debugfs_create_file("rcuboost", 0444, rcudir, NULL,
&rcu_node_boost_fops);
}
#else /* #ifdef CONFIG_RCU_BOOST */
static int rcu_boost_trace_create_file(struct dentry *rcudir)
{
return 0; /* There cannot be an error if we didn't create it! */
}
#endif /* #else #ifdef CONFIG_RCU_BOOST */
#endif /* #ifdef CONFIG_RCU_BOOST */
static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
{
@@ -283,8 +261,9 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
struct rcu_node *rnp;
gpnum = rsp->gpnum;
seq_printf(m, "%s: c=%lu g=%lu s=%d jfq=%ld j=%x ",
rsp->name, rsp->completed, gpnum, rsp->fqs_state,
seq_printf(m, "c=%ld g=%ld s=%d jfq=%ld j=%x ",
ulong2long(rsp->completed), ulong2long(gpnum),
rsp->fqs_state,
(long)(rsp->jiffies_force_qs - jiffies),
(int)(jiffies & 0xffff));
seq_printf(m, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
@@ -306,26 +285,24 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp)
seq_puts(m, "\n");
}
static int show_rcuhier(struct seq_file *m, void *unused)
static int show_rcuhier(struct seq_file *m, void *v)
{
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
print_one_rcu_state(m, rsp);
struct rcu_state *rsp = (struct rcu_state *)m->private;
print_one_rcu_state(m, rsp);
return 0;
}
static int rcuhier_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcuhier, NULL);
return single_open(file, show_rcuhier, inode->i_private);
}
static const struct file_operations rcuhier_fops = {
.owner = THIS_MODULE,
.open = rcuhier_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.llseek = no_llseek,
.release = seq_release,
};
static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
@@ -338,42 +315,42 @@ static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
struct rcu_node *rnp = &rsp->node[0];
raw_spin_lock_irqsave(&rnp->lock, flags);
completed = rsp->completed;
gpnum = rsp->gpnum;
if (rsp->completed == rsp->gpnum)
completed = ACCESS_ONCE(rsp->completed);
gpnum = ACCESS_ONCE(rsp->gpnum);
if (completed == gpnum)
gpage = 0;
else
gpage = jiffies - rsp->gp_start;
gpmax = rsp->gp_max;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
seq_printf(m, "%s: completed=%ld gpnum=%lu age=%ld max=%ld\n",
rsp->name, completed, gpnum, gpage, gpmax);
seq_printf(m, "completed=%ld gpnum=%ld age=%ld max=%ld\n",
ulong2long(completed), ulong2long(gpnum), gpage, gpmax);
}
static int show_rcugp(struct seq_file *m, void *unused)
static int show_rcugp(struct seq_file *m, void *v)
{
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
show_one_rcugp(m, rsp);
struct rcu_state *rsp = (struct rcu_state *)m->private;
show_one_rcugp(m, rsp);
return 0;
}
static int rcugp_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcugp, NULL);
return single_open(file, show_rcugp, inode->i_private);
}
static const struct file_operations rcugp_fops = {
.owner = THIS_MODULE,
.open = rcugp_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.llseek = no_llseek,
.release = seq_release,
};
static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
{
if (!rdp->beenonline)
return;
seq_printf(m, "%3d%cnp=%ld ",
rdp->cpu,
cpu_is_offline(rdp->cpu) ? '!' : ' ',
@@ -389,34 +366,30 @@ static void print_one_rcu_pending(struct seq_file *m, struct rcu_data *rdp)
rdp->n_rp_need_nothing);
}
static int show_rcu_pending(struct seq_file *m, void *unused)
static int show_rcu_pending(struct seq_file *m, void *v)
{
int cpu;
struct rcu_data *rdp;
struct rcu_state *rsp;
for_each_rcu_flavor(rsp) {
seq_printf(m, "%s:\n", rsp->name);
for_each_possible_cpu(cpu) {
rdp = per_cpu_ptr(rsp->rda, cpu);
if (rdp->beenonline)
print_one_rcu_pending(m, rdp);
}
}
print_one_rcu_pending(m, (struct rcu_data *)v);
return 0;
}
static const struct seq_operations rcu_pending_op = {
.start = r_start,
.next = r_next,
.stop = r_stop,
.show = show_rcu_pending,
};
static int rcu_pending_open(struct inode *inode, struct file *file)
{
return single_open(file, show_rcu_pending, NULL);
return r_open(inode, file, &rcu_pending_op);
}
static const struct file_operations rcu_pending_fops = {
.owner = THIS_MODULE,
.open = rcu_pending_open,
.read = seq_read,
.llseek = seq_lseek,
.release = single_release,
.llseek = no_llseek,
.release = seq_release,
};
static int show_rcutorture(struct seq_file *m, void *unused)
@@ -446,43 +419,58 @@ static struct dentry *rcudir;
static int __init rcutree_trace_init(void)
{
struct rcu_state *rsp;
struct dentry *retval;
struct dentry *rspdir;
rcudir = debugfs_create_dir("rcu", NULL);
if (!rcudir)
goto free_out;
retval = debugfs_create_file("rcubarrier", 0444, rcudir,
NULL, &rcubarrier_fops);
if (!retval)
goto free_out;
for_each_rcu_flavor(rsp) {
rspdir = debugfs_create_dir(rsp->name, rcudir);
if (!rspdir)
goto free_out;
retval = debugfs_create_file("rcudata", 0444, rcudir,
NULL, &rcudata_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcudata", 0444,
rspdir, rsp, &rcudata_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcudata.csv", 0444, rcudir,
NULL, &rcudata_csv_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcuexp", 0444,
rspdir, rsp, &rcuexp_fops);
if (!retval)
goto free_out;
if (rcu_boost_trace_create_file(rcudir))
goto free_out;
retval = debugfs_create_file("rcu_pending", 0444,
rspdir, rsp, &rcu_pending_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcubarrier", 0444,
rspdir, rsp, &rcubarrier_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcuhier", 0444, rcudir,
NULL, &rcuhier_fops);
if (!retval)
goto free_out;
#ifdef CONFIG_RCU_BOOST
if (rsp == &rcu_preempt_state) {
retval = debugfs_create_file("rcuboost", 0444,
rspdir, NULL, &rcu_node_boost_fops);
if (!retval)
goto free_out;
}
#endif
retval = debugfs_create_file("rcu_pending", 0444, rcudir,
NULL, &rcu_pending_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcugp", 0444,
rspdir, rsp, &rcugp_fops);
if (!retval)
goto free_out;
retval = debugfs_create_file("rcuhier", 0444,
rspdir, rsp, &rcuhier_fops);
if (!retval)
goto free_out;
}
retval = debugfs_create_file("rcutorture", 0444, rcudir,
NULL, &rcutorture_fops);

8
kernel/sched/core.c
View File

@@ -1887,7 +1887,7 @@ context_switch(struct rq *rq, struct task_struct *prev,
#endif
/* Here we just switch the register state and the stack. */
rcu_switch(prev, next);
rcu_user_hooks_switch(prev, next);
switch_to(prev, next, prev);
barrier();
@@ -8076,3 +8076,9 @@ struct cgroup_subsys cpuacct_subsys = {
.base_cftypes = files,
};
#endif /* CONFIG_CGROUP_CPUACCT */
void dump_cpu_task(int cpu)
{
pr_info("Task dump for CPU %d:\n", cpu);
sched_show_task(cpu_curr(cpu));
}

16
kernel/srcu.c
View File

@@ -16,8 +16,10 @@
* Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
*
* Copyright (C) IBM Corporation, 2006
* Copyright (C) Fujitsu, 2012
*
* Author: Paul McKenney <paulmck@us.ibm.com>
* Lai Jiangshan <laijs@cn.fujitsu.com>
*
* For detailed explanation of Read-Copy Update mechanism see -
* Documentation/RCU/ *.txt
@@ -34,6 +36,10 @@
#include <linux/delay.h>
#include <linux/srcu.h>
#include <trace/events/rcu.h>
#include "rcu.h"
/*
* Initialize an rcu_batch structure to empty.
*/
@@ -92,9 +98,6 @@ static inline void rcu_batch_move(struct rcu_batch *to, struct rcu_batch *from)
}
}
/* single-thread state-machine */
static void process_srcu(struct work_struct *work);
static int init_srcu_struct_fields(struct srcu_struct *sp)
{
sp->completed = 0;
@@ -464,7 +467,9 @@ static void __synchronize_srcu(struct srcu_struct *sp, int trycount)
*/
void synchronize_srcu(struct srcu_struct *sp)
{
__synchronize_srcu(sp, SYNCHRONIZE_SRCU_TRYCOUNT);
__synchronize_srcu(sp, rcu_expedited
? SYNCHRONIZE_SRCU_EXP_TRYCOUNT
: SYNCHRONIZE_SRCU_TRYCOUNT);
}
EXPORT_SYMBOL_GPL(synchronize_srcu);
@@ -637,7 +642,7 @@ static void srcu_reschedule(struct srcu_struct *sp)
/*
* This is the work-queue function that handles SRCU grace periods.
*/
static void process_srcu(struct work_struct *work)
void process_srcu(struct work_struct *work)
{
struct srcu_struct *sp;
@@ -648,3 +653,4 @@ static void process_srcu(struct work_struct *work)
srcu_invoke_callbacks(sp);
srcu_reschedule(sp);
}
EXPORT_SYMBOL_GPL(process_srcu);