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-rw-r--r--kernel/rcu.h7
-rw-r--r--kernel/rcupdate.c2
-rw-r--r--kernel/rcutiny.c19
-rw-r--r--kernel/rcutree.c151
-rw-r--r--kernel/rcutree_plugin.h56
5 files changed, 173 insertions, 62 deletions
diff --git a/kernel/rcu.h b/kernel/rcu.h
index 7713196..7859a0a 100644
--- a/kernel/rcu.h
+++ b/kernel/rcu.h
@@ -122,4 +122,11 @@ int rcu_jiffies_till_stall_check(void);
#endif /* #ifdef CONFIG_RCU_STALL_COMMON */
+/*
+ * Strings used in tracepoints need to be exported via the
+ * tracing system such that tools like perf and trace-cmd can
+ * translate the string address pointers to actual text.
+ */
+#define TPS(x) tracepoint_string(x)
+
#endif /* __LINUX_RCU_H */
diff --git a/kernel/rcupdate.c b/kernel/rcupdate.c
index 3b3c046..c07af1c 100644
--- a/kernel/rcupdate.c
+++ b/kernel/rcupdate.c
@@ -298,7 +298,7 @@ EXPORT_SYMBOL_GPL(do_trace_rcu_torture_read);
#endif
int rcu_cpu_stall_suppress __read_mostly; /* 1 = suppress stall warnings. */
-int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
+static int rcu_cpu_stall_timeout __read_mostly = CONFIG_RCU_CPU_STALL_TIMEOUT;
module_param(rcu_cpu_stall_suppress, int, 0644);
module_param(rcu_cpu_stall_timeout, int, 0644);
diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c
index 0fa061d..312e9709 100644
--- a/kernel/rcutiny.c
+++ b/kernel/rcutiny.c
@@ -35,6 +35,7 @@
#include <linux/time.h>
#include <linux/cpu.h>
#include <linux/prefetch.h>
+#include <linux/ftrace_event.h>
#ifdef CONFIG_RCU_TRACE
#include <trace/events/rcu.h>
@@ -58,16 +59,17 @@ static long long rcu_dynticks_nesting = DYNTICK_TASK_EXIT_IDLE;
static void rcu_idle_enter_common(long long newval)
{
if (newval) {
- RCU_TRACE(trace_rcu_dyntick("--=",
+ RCU_TRACE(trace_rcu_dyntick(TPS("--="),
rcu_dynticks_nesting, newval));
rcu_dynticks_nesting = newval;
return;
}
- RCU_TRACE(trace_rcu_dyntick("Start", rcu_dynticks_nesting, newval));
+ RCU_TRACE(trace_rcu_dyntick(TPS("Start"),
+ rcu_dynticks_nesting, newval));
if (!is_idle_task(current)) {
struct task_struct *idle = idle_task(smp_processor_id());
- RCU_TRACE(trace_rcu_dyntick("Error on entry: not idle task",
+ RCU_TRACE(trace_rcu_dyntick(TPS("Entry error: not idle task"),
rcu_dynticks_nesting, newval));
ftrace_dump(DUMP_ALL);
WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s",
@@ -120,15 +122,15 @@ EXPORT_SYMBOL_GPL(rcu_irq_exit);
static void rcu_idle_exit_common(long long oldval)
{
if (oldval) {
- RCU_TRACE(trace_rcu_dyntick("++=",
+ RCU_TRACE(trace_rcu_dyntick(TPS("++="),
oldval, rcu_dynticks_nesting));
return;
}
- RCU_TRACE(trace_rcu_dyntick("End", oldval, rcu_dynticks_nesting));
+ RCU_TRACE(trace_rcu_dyntick(TPS("End"), oldval, rcu_dynticks_nesting));
if (!is_idle_task(current)) {
struct task_struct *idle = idle_task(smp_processor_id());
- RCU_TRACE(trace_rcu_dyntick("Error on exit: not idle task",
+ RCU_TRACE(trace_rcu_dyntick(TPS("Exit error: not idle task"),
oldval, rcu_dynticks_nesting));
ftrace_dump(DUMP_ALL);
WARN_ONCE(1, "Current pid: %d comm: %s / Idle pid: %d comm: %s",
@@ -273,7 +275,7 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
if (&rcp->rcucblist == rcp->donetail) {
RCU_TRACE(trace_rcu_batch_start(rcp->name, 0, 0, -1));
RCU_TRACE(trace_rcu_batch_end(rcp->name, 0,
- ACCESS_ONCE(rcp->rcucblist),
+ !!ACCESS_ONCE(rcp->rcucblist),
need_resched(),
is_idle_task(current),
false));
@@ -304,7 +306,8 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp)
RCU_TRACE(cb_count++);
}
RCU_TRACE(rcu_trace_sub_qlen(rcp, cb_count));
- RCU_TRACE(trace_rcu_batch_end(rcp->name, cb_count, 0, need_resched(),
+ RCU_TRACE(trace_rcu_batch_end(rcp->name,
+ cb_count, 0, need_resched(),
is_idle_task(current),
false));
}
diff --git a/kernel/rcutree.c b/kernel/rcutree.c
index 981d0c1..240604a 100644
--- a/kernel/rcutree.c
+++ b/kernel/rcutree.c
@@ -61,13 +61,6 @@
#include "rcu.h"
-/*
- * Strings used in tracepoints need to be exported via the
- * tracing system such that tools like perf and trace-cmd can
- * translate the string address pointers to actual text.
- */
-#define TPS(x) tracepoint_string(x)
-
/* Data structures. */
static struct lock_class_key rcu_node_class[RCU_NUM_LVLS];
@@ -222,7 +215,7 @@ void rcu_note_context_switch(int cpu)
}
EXPORT_SYMBOL_GPL(rcu_note_context_switch);
-DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
+static DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = {
.dynticks_nesting = DYNTICK_TASK_EXIT_IDLE,
.dynticks = ATOMIC_INIT(1),
#ifdef CONFIG_NO_HZ_FULL_SYSIDLE
@@ -371,7 +364,8 @@ static void rcu_eqs_enter_common(struct rcu_dynticks *rdtp, long long oldval,
{
trace_rcu_dyntick(TPS("Start"), oldval, rdtp->dynticks_nesting);
if (!user && !is_idle_task(current)) {
- struct task_struct *idle = idle_task(smp_processor_id());
+ struct task_struct *idle __maybe_unused =
+ idle_task(smp_processor_id());
trace_rcu_dyntick(TPS("Error on entry: not idle task"), oldval, 0);
ftrace_dump(DUMP_ORIG);
@@ -407,7 +401,7 @@ static void rcu_eqs_enter(bool user)
long long oldval;
struct rcu_dynticks *rdtp;
- rdtp = &__get_cpu_var(rcu_dynticks);
+ rdtp = this_cpu_ptr(&rcu_dynticks);
oldval = rdtp->dynticks_nesting;
WARN_ON_ONCE((oldval & DYNTICK_TASK_NEST_MASK) == 0);
if ((oldval & DYNTICK_TASK_NEST_MASK) == DYNTICK_TASK_NEST_VALUE)
@@ -435,7 +429,7 @@ void rcu_idle_enter(void)
local_irq_save(flags);
rcu_eqs_enter(false);
- rcu_sysidle_enter(&__get_cpu_var(rcu_dynticks), 0);
+ rcu_sysidle_enter(this_cpu_ptr(&rcu_dynticks), 0);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(rcu_idle_enter);
@@ -478,7 +472,7 @@ void rcu_irq_exit(void)
struct rcu_dynticks *rdtp;
local_irq_save(flags);
- rdtp = &__get_cpu_var(rcu_dynticks);
+ rdtp = this_cpu_ptr(&rcu_dynticks);
oldval = rdtp->dynticks_nesting;
rdtp->dynticks_nesting--;
WARN_ON_ONCE(rdtp->dynticks_nesting < 0);
@@ -508,7 +502,8 @@ static void rcu_eqs_exit_common(struct rcu_dynticks *rdtp, long long oldval,
rcu_cleanup_after_idle(smp_processor_id());
trace_rcu_dyntick(TPS("End"), oldval, rdtp->dynticks_nesting);
if (!user && !is_idle_task(current)) {
- struct task_struct *idle = idle_task(smp_processor_id());
+ struct task_struct *idle __maybe_unused =
+ idle_task(smp_processor_id());
trace_rcu_dyntick(TPS("Error on exit: not idle task"),
oldval, rdtp->dynticks_nesting);
@@ -528,7 +523,7 @@ static void rcu_eqs_exit(bool user)
struct rcu_dynticks *rdtp;
long long oldval;
- rdtp = &__get_cpu_var(rcu_dynticks);
+ rdtp = this_cpu_ptr(&rcu_dynticks);
oldval = rdtp->dynticks_nesting;
WARN_ON_ONCE(oldval < 0);
if (oldval & DYNTICK_TASK_NEST_MASK)
@@ -555,7 +550,7 @@ void rcu_idle_exit(void)
local_irq_save(flags);
rcu_eqs_exit(false);
- rcu_sysidle_exit(&__get_cpu_var(rcu_dynticks), 0);
+ rcu_sysidle_exit(this_cpu_ptr(&rcu_dynticks), 0);
local_irq_restore(flags);
}
EXPORT_SYMBOL_GPL(rcu_idle_exit);
@@ -599,7 +594,7 @@ void rcu_irq_enter(void)
long long oldval;
local_irq_save(flags);
- rdtp = &__get_cpu_var(rcu_dynticks);
+ rdtp = this_cpu_ptr(&rcu_dynticks);
oldval = rdtp->dynticks_nesting;
rdtp->dynticks_nesting++;
WARN_ON_ONCE(rdtp->dynticks_nesting == 0);
@@ -620,7 +615,7 @@ void rcu_irq_enter(void)
*/
void rcu_nmi_enter(void)
{
- struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks);
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
if (rdtp->dynticks_nmi_nesting == 0 &&
(atomic_read(&rdtp->dynticks) & 0x1))
@@ -642,7 +637,7 @@ void rcu_nmi_enter(void)
*/
void rcu_nmi_exit(void)
{
- struct rcu_dynticks *rdtp = &__get_cpu_var(rcu_dynticks);
+ struct rcu_dynticks *rdtp = this_cpu_ptr(&rcu_dynticks);
if (rdtp->dynticks_nmi_nesting == 0 ||
--rdtp->dynticks_nmi_nesting != 0)
@@ -716,7 +711,7 @@ bool rcu_lockdep_current_cpu_online(void)
if (in_nmi())
return 1;
preempt_disable();
- rdp = &__get_cpu_var(rcu_sched_data);
+ rdp = this_cpu_ptr(&rcu_sched_data);
rnp = rdp->mynode;
ret = (rdp->grpmask & rnp->qsmaskinit) ||
!rcu_scheduler_fully_active;
@@ -736,7 +731,7 @@ EXPORT_SYMBOL_GPL(rcu_lockdep_current_cpu_online);
*/
static int rcu_is_cpu_rrupt_from_idle(void)
{
- return __get_cpu_var(rcu_dynticks).dynticks_nesting <= 1;
+ return __this_cpu_read(rcu_dynticks.dynticks_nesting) <= 1;
}
/*
@@ -815,8 +810,11 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp,
static void record_gp_stall_check_time(struct rcu_state *rsp)
{
- rsp->gp_start = jiffies;
- rsp->jiffies_stall = jiffies + rcu_jiffies_till_stall_check();
+ unsigned long j = ACCESS_ONCE(jiffies);
+
+ rsp->gp_start = j;
+ smp_wmb(); /* Record start time before stall time. */
+ rsp->jiffies_stall = j + rcu_jiffies_till_stall_check();
}
/*
@@ -945,17 +943,48 @@ static void print_cpu_stall(struct rcu_state *rsp)
static void check_cpu_stall(struct rcu_state *rsp, struct rcu_data *rdp)
{
+ unsigned long completed;
+ unsigned long gpnum;
+ unsigned long gps;
unsigned long j;
unsigned long js;
struct rcu_node *rnp;
- if (rcu_cpu_stall_suppress)
+ if (rcu_cpu_stall_suppress || !rcu_gp_in_progress(rsp))
return;
j = ACCESS_ONCE(jiffies);
+
+ /*
+ * Lots of memory barriers to reject false positives.
+ *
+ * The idea is to pick up rsp->gpnum, then rsp->jiffies_stall,
+ * then rsp->gp_start, and finally rsp->completed. These values
+ * are updated in the opposite order with memory barriers (or
+ * equivalent) during grace-period initialization and cleanup.
+ * Now, a false positive can occur if we get an new value of
+ * rsp->gp_start and a old value of rsp->jiffies_stall. But given
+ * the memory barriers, the only way that this can happen is if one
+ * grace period ends and another starts between these two fetches.
+ * Detect this by comparing rsp->completed with the previous fetch
+ * from rsp->gpnum.
+ *
+ * Given this check, comparisons of jiffies, rsp->jiffies_stall,
+ * and rsp->gp_start suffice to forestall false positives.
+ */
+ gpnum = ACCESS_ONCE(rsp->gpnum);
+ smp_rmb(); /* Pick up ->gpnum first... */
js = ACCESS_ONCE(rsp->jiffies_stall);
+ smp_rmb(); /* ...then ->jiffies_stall before the rest... */
+ gps = ACCESS_ONCE(rsp->gp_start);
+ smp_rmb(); /* ...and finally ->gp_start before ->completed. */
+ completed = ACCESS_ONCE(rsp->completed);
+ if (ULONG_CMP_GE(completed, gpnum) ||
+ ULONG_CMP_LT(j, js) ||
+ ULONG_CMP_GE(gps, js))
+ return; /* No stall or GP completed since entering function. */
rnp = rdp->mynode;
if (rcu_gp_in_progress(rsp) &&
- (ACCESS_ONCE(rnp->qsmask) & rdp->grpmask) && ULONG_CMP_GE(j, js)) {
+ (ACCESS_ONCE(rnp->qsmask) & rdp->grpmask)) {
/* We haven't checked in, so go dump stack. */
print_cpu_stall(rsp);
@@ -1310,7 +1339,7 @@ static void note_gp_changes(struct rcu_state *rsp, struct rcu_data *rdp)
}
/*
- * Initialize a new grace period.
+ * Initialize a new grace period. Return 0 if no grace period required.
*/
static int rcu_gp_init(struct rcu_state *rsp)
{
@@ -1319,18 +1348,27 @@ static int rcu_gp_init(struct rcu_state *rsp)
rcu_bind_gp_kthread();
raw_spin_lock_irq(&rnp->lock);
+ if (rsp->gp_flags == 0) {
+ /* Spurious wakeup, tell caller to go back to sleep. */
+ raw_spin_unlock_irq(&rnp->lock);
+ return 0;
+ }
rsp->gp_flags = 0; /* Clear all flags: New grace period. */
- if (rcu_gp_in_progress(rsp)) {
- /* Grace period already in progress, don't start another. */
+ if (WARN_ON_ONCE(rcu_gp_in_progress(rsp))) {
+ /*
+ * Grace period already in progress, don't start another.
+ * Not supposed to be able to happen.
+ */
raw_spin_unlock_irq(&rnp->lock);
return 0;
}
/* Advance to a new grace period and initialize state. */
+ record_gp_stall_check_time(rsp);
+ smp_wmb(); /* Record GP times before starting GP. */
rsp->gpnum++;
trace_rcu_grace_period(rsp->name, rsp->gpnum, TPS("start"));
- record_gp_stall_check_time(rsp);
raw_spin_unlock_irq(&rnp->lock);
/* Exclude any concurrent CPU-hotplug operations. */
@@ -1379,7 +1417,7 @@ static int rcu_gp_init(struct rcu_state *rsp)
/*
* Do one round of quiescent-state forcing.
*/
-int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in)
+static int rcu_gp_fqs(struct rcu_state *rsp, int fqs_state_in)
{
int fqs_state = fqs_state_in;
bool isidle = false;
@@ -1464,8 +1502,12 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
rsp->fqs_state = RCU_GP_IDLE;
rdp = this_cpu_ptr(rsp->rda);
rcu_advance_cbs(rsp, rnp, rdp); /* Reduce false positives below. */
- if (cpu_needs_another_gp(rsp, rdp))
- rsp->gp_flags = 1;
+ if (cpu_needs_another_gp(rsp, rdp)) {
+ rsp->gp_flags = RCU_GP_FLAG_INIT;
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("newreq"));
+ }
raw_spin_unlock_irq(&rnp->lock);
}
@@ -1475,6 +1517,7 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
static int __noreturn rcu_gp_kthread(void *arg)
{
int fqs_state;
+ int gf;
unsigned long j;
int ret;
struct rcu_state *rsp = arg;
@@ -1484,14 +1527,19 @@ static int __noreturn rcu_gp_kthread(void *arg)
/* Handle grace-period start. */
for (;;) {
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("reqwait"));
wait_event_interruptible(rsp->gp_wq,
- rsp->gp_flags &
+ ACCESS_ONCE(rsp->gp_flags) &
RCU_GP_FLAG_INIT);
- if ((rsp->gp_flags & RCU_GP_FLAG_INIT) &&
- rcu_gp_init(rsp))
+ if (rcu_gp_init(rsp))
break;
cond_resched();
flush_signals(current);
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("reqwaitsig"));
}
/* Handle quiescent-state forcing. */
@@ -1501,10 +1549,16 @@ static int __noreturn rcu_gp_kthread(void *arg)
j = HZ;
jiffies_till_first_fqs = HZ;
}
+ ret = 0;
for (;;) {
- rsp->jiffies_force_qs = jiffies + j;
+ if (!ret)
+ rsp->jiffies_force_qs = jiffies + j;
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("fqswait"));
ret = wait_event_interruptible_timeout(rsp->gp_wq,
- (rsp->gp_flags & RCU_GP_FLAG_FQS) ||
+ ((gf = ACCESS_ONCE(rsp->gp_flags)) &
+ RCU_GP_FLAG_FQS) ||
(!ACCESS_ONCE(rnp->qsmask) &&
!rcu_preempt_blocked_readers_cgp(rnp)),
j);
@@ -1513,13 +1567,23 @@ static int __noreturn rcu_gp_kthread(void *arg)
!rcu_preempt_blocked_readers_cgp(rnp))
break;
/* If time for quiescent-state forcing, do it. */
- if (ret == 0 || (rsp->gp_flags & RCU_GP_FLAG_FQS)) {
+ if (ULONG_CMP_GE(jiffies, rsp->jiffies_force_qs) ||
+ (gf & RCU_GP_FLAG_FQS)) {
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("fqsstart"));
fqs_state = rcu_gp_fqs(rsp, fqs_state);
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("fqsend"));
cond_resched();
} else {
/* Deal with stray signal. */
cond_resched();
flush_signals(current);
+ trace_rcu_grace_period(rsp->name,
+ ACCESS_ONCE(rsp->gpnum),
+ TPS("fqswaitsig"));
}
j = jiffies_till_next_fqs;
if (j > HZ) {
@@ -1567,6 +1631,8 @@ rcu_start_gp_advanced(struct rcu_state *rsp, struct rcu_node *rnp,
return;
}
rsp->gp_flags = RCU_GP_FLAG_INIT;
+ trace_rcu_grace_period(rsp->name, ACCESS_ONCE(rsp->gpnum),
+ TPS("newreq"));
/*
* We can't do wakeups while holding the rnp->lock, as that
@@ -2738,10 +2804,13 @@ static int rcu_cpu_has_callbacks(int cpu, bool *all_lazy)
for_each_rcu_flavor(rsp) {
rdp = per_cpu_ptr(rsp->rda, cpu);
- if (rdp->qlen != rdp->qlen_lazy)
+ if (!rdp->nxtlist)
+ continue;
+ hc = true;
+ if (rdp->qlen != rdp->qlen_lazy || !all_lazy) {
al = false;
- if (rdp->nxtlist)
- hc = true;
+ break;
+ }
}
if (all_lazy)
*all_lazy = al;
@@ -3308,8 +3377,8 @@ void __init rcu_init(void)
rcu_bootup_announce();
rcu_init_geometry();
- rcu_init_one(&rcu_sched_state, &rcu_sched_data);
rcu_init_one(&rcu_bh_state, &rcu_bh_data);
+ rcu_init_one(&rcu_sched_state, &rcu_sched_data);
__rcu_init_preempt();
open_softirq(RCU_SOFTIRQ, rcu_process_callbacks);
diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h
index 2c15d7c..8d85a5c 100644
--- a/kernel/rcutree_plugin.h
+++ b/kernel/rcutree_plugin.h
@@ -96,10 +96,15 @@ static void __init rcu_bootup_announce_oddness(void)
#endif /* #ifdef CONFIG_RCU_NOCB_CPU_ZERO */
#ifdef CONFIG_RCU_NOCB_CPU_ALL
pr_info("\tOffload RCU callbacks from all CPUs\n");
- cpumask_setall(rcu_nocb_mask);
+ cpumask_copy(rcu_nocb_mask, cpu_possible_mask);
#endif /* #ifdef CONFIG_RCU_NOCB_CPU_ALL */
#endif /* #ifndef CONFIG_RCU_NOCB_CPU_NONE */
if (have_rcu_nocb_mask) {
+ if (!cpumask_subset(rcu_nocb_mask, cpu_possible_mask)) {
+ pr_info("\tNote: kernel parameter 'rcu_nocbs=' contains nonexistent CPUs.\n");
+ cpumask_and(rcu_nocb_mask, cpu_possible_mask,
+ rcu_nocb_mask);
+ }
cpulist_scnprintf(nocb_buf, sizeof(nocb_buf), rcu_nocb_mask);
pr_info("\tOffload RCU callbacks from CPUs: %s.\n", nocb_buf);
if (rcu_nocb_poll)
@@ -660,7 +665,7 @@ static void rcu_preempt_check_callbacks(int cpu)
static void rcu_preempt_do_callbacks(void)
{
- rcu_do_batch(&rcu_preempt_state, &__get_cpu_var(rcu_preempt_data));
+ rcu_do_batch(&rcu_preempt_state, this_cpu_ptr(&rcu_preempt_data));
}
#endif /* #ifdef CONFIG_RCU_BOOST */
@@ -1332,7 +1337,7 @@ static void invoke_rcu_callbacks_kthread(void)
*/
static bool rcu_is_callbacks_kthread(void)
{
- return __get_cpu_var(rcu_cpu_kthread_task) == current;
+ return __this_cpu_read(rcu_cpu_kthread_task) == current;
}
#define RCU_BOOST_DELAY_JIFFIES DIV_ROUND_UP(CONFIG_RCU_BOOST_DELAY * HZ, 1000)
@@ -1382,8 +1387,8 @@ static int rcu_spawn_one_boost_kthread(struct rcu_state *rsp,
static void rcu_kthread_do_work(void)
{
- rcu_do_batch(&rcu_sched_state, &__get_cpu_var(rcu_sched_data));
- rcu_do_batch(&rcu_bh_state, &__get_cpu_var(rcu_bh_data));
+ rcu_do_batch(&rcu_sched_state, this_cpu_ptr(&rcu_sched_data));
+ rcu_do_batch(&rcu_bh_state, this_cpu_ptr(&rcu_bh_data));
rcu_preempt_do_callbacks();
}
@@ -1402,7 +1407,7 @@ static void rcu_cpu_kthread_park(unsigned int cpu)
static int rcu_cpu_kthread_should_run(unsigned int cpu)
{
- return __get_cpu_var(rcu_cpu_has_work);
+ return __this_cpu_read(rcu_cpu_has_work);
}
/*
@@ -1412,8 +1417,8 @@ static int rcu_cpu_kthread_should_run(unsigned int cpu)
*/
static void rcu_cpu_kthread(unsigned int cpu)
{
- unsigned int *statusp = &__get_cpu_var(rcu_cpu_kthread_status);
- char work, *workp = &__get_cpu_var(rcu_cpu_has_work);
+ unsigned int *statusp = this_cpu_ptr(&rcu_cpu_kthread_status);
+ char work, *workp = this_cpu_ptr(&rcu_cpu_has_work);
int spincnt;
for (spincnt = 0; spincnt < 10; spincnt++) {
@@ -2110,15 +2115,22 @@ static void __call_rcu_nocb_enqueue(struct rcu_data *rdp,
/* If we are not being polled and there is a kthread, awaken it ... */
t = ACCESS_ONCE(rdp->nocb_kthread);
- if (rcu_nocb_poll | !t)
+ if (rcu_nocb_poll || !t) {
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("WakeNotPoll"));
return;
+ }
len = atomic_long_read(&rdp->nocb_q_count);
if (old_rhpp == &rdp->nocb_head) {
wake_up(&rdp->nocb_wq); /* ... only if queue was empty ... */
rdp->qlen_last_fqs_check = 0;
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeEmpty"));
} else if (len > rdp->qlen_last_fqs_check + qhimark) {
wake_up_process(t); /* ... or if many callbacks queued. */
rdp->qlen_last_fqs_check = LONG_MAX / 2;
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeOvf"));
+ } else {
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu, TPS("WakeNot"));
}
return;
}
@@ -2142,10 +2154,12 @@ static bool __call_rcu_nocb(struct rcu_data *rdp, struct rcu_head *rhp,
if (__is_kfree_rcu_offset((unsigned long)rhp->func))
trace_rcu_kfree_callback(rdp->rsp->name, rhp,
(unsigned long)rhp->func,
- rdp->qlen_lazy, rdp->qlen);
+ -atomic_long_read(&rdp->nocb_q_count_lazy),
+ -atomic_long_read(&rdp->nocb_q_count));
else
trace_rcu_callback(rdp->rsp->name, rhp,
- rdp->qlen_lazy, rdp->qlen);
+ -atomic_long_read(&rdp->nocb_q_count_lazy),
+ -atomic_long_read(&rdp->nocb_q_count));
return 1;
}
@@ -2223,6 +2237,7 @@ static void rcu_nocb_wait_gp(struct rcu_data *rdp)
static int rcu_nocb_kthread(void *arg)
{
int c, cl;
+ bool firsttime = 1;
struct rcu_head *list;
struct rcu_head *next;
struct rcu_head **tail;
@@ -2231,14 +2246,27 @@ static int rcu_nocb_kthread(void *arg)
/* Each pass through this loop invokes one batch of callbacks */
for (;;) {
/* If not polling, wait for next batch of callbacks. */
- if (!rcu_nocb_poll)
+ if (!rcu_nocb_poll) {
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("Sleep"));
wait_event_interruptible(rdp->nocb_wq, rdp->nocb_head);
+ } else if (firsttime) {
+ firsttime = 0;
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("Poll"));
+ }
list = ACCESS_ONCE(rdp->nocb_head);
if (!list) {
+ if (!rcu_nocb_poll)
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("WokeEmpty"));
schedule_timeout_interruptible(1);
flush_signals(current);
continue;
}
+ firsttime = 1;
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("WokeNonEmpty"));
/*
* Extract queued callbacks, update counts, and wait
@@ -2259,7 +2287,11 @@ static int rcu_nocb_kthread(void *arg)
next = list->next;
/* Wait for enqueuing to complete, if needed. */
while (next == NULL && &list->next != tail) {
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("WaitQueue"));
schedule_timeout_interruptible(1);
+ trace_rcu_nocb_wake(rdp->rsp->name, rdp->cpu,
+ TPS("WokeQueue"));
next = list->next;
}
debug_rcu_head_unqueue(list);
generated by cgit v0.10.2 at 2024-08-28 12:22:21 (GMT)