forked from Minki/linux
rcu: add tracing for RCU's kthread run states.
Add tracing to help debugging situations when RCU's kthreads are not running but are supposed to be. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Reviewed-by: Josh Triplett <josh@joshtriplett.org>
This commit is contained in:
Paul E. McKenney
Paul E. McKenney
parent
0ac3d136b2
commit
d71df90ead
@ -91,8 +91,9 @@ EXPORT_SYMBOL_GPL(rcu_scheduler_active);
|
||||
* handle all flavors of RCU.
|
||||
*/
|
||||
static DEFINE_PER_CPU(struct task_struct *, rcu_cpu_kthread_task);
|
||||
DEFINE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
|
||||
static DEFINE_PER_CPU(wait_queue_head_t, rcu_cpu_wq);
|
||||
static DEFINE_PER_CPU(char, rcu_cpu_has_work);
|
||||
DEFINE_PER_CPU(char, rcu_cpu_has_work);
|
||||
static char rcu_kthreads_spawnable;
|
||||
|
||||
static void rcu_node_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
|
||||
@ -1563,11 +1564,13 @@ static int rcu_cpu_kthread(void *arg)
|
||||
int cpu = (int)(long)arg;
|
||||
unsigned long flags;
|
||||
int spincnt = 0;
|
||||
unsigned int *statusp = &per_cpu(rcu_cpu_kthread_status, cpu);
|
||||
wait_queue_head_t *wqp = &per_cpu(rcu_cpu_wq, cpu);
|
||||
char work;
|
||||
char *workp = &per_cpu(rcu_cpu_has_work, cpu);
|
||||
|
||||
for (;;) {
|
||||
*statusp = RCU_KTHREAD_WAITING;
|
||||
wait_event_interruptible(*wqp,
|
||||
*workp != 0 || kthread_should_stop());
|
||||
local_bh_disable();
|
||||
@ -1575,6 +1578,7 @@ static int rcu_cpu_kthread(void *arg)
|
||||
local_bh_enable();
|
||||
break;
|
||||
}
|
||||
*statusp = RCU_KTHREAD_RUNNING;
|
||||
local_irq_save(flags);
|
||||
work = *workp;
|
||||
*workp = 0;
|
||||
@ -1587,10 +1591,12 @@ static int rcu_cpu_kthread(void *arg)
|
||||
else
|
||||
spincnt = 0;
|
||||
if (spincnt > 10) {
|
||||
*statusp = RCU_KTHREAD_YIELDING;
|
||||
rcu_yield(rcu_cpu_kthread_timer, (unsigned long)cpu);
|
||||
spincnt = 0;
|
||||
}
|
||||
}
|
||||
*statusp = RCU_KTHREAD_STOPPED;
|
||||
return 0;
|
||||
}
|
||||
|
||||
@ -1637,10 +1643,12 @@ static int rcu_node_kthread(void *arg)
|
||||
struct task_struct *t;
|
||||
|
||||
for (;;) {
|
||||
rnp->node_kthread_status = RCU_KTHREAD_WAITING;
|
||||
wait_event_interruptible(rnp->node_wq, rnp->wakemask != 0 ||
|
||||
kthread_should_stop());
|
||||
if (kthread_should_stop())
|
||||
break;
|
||||
rnp->node_kthread_status = RCU_KTHREAD_RUNNING;
|
||||
raw_spin_lock_irqsave(&rnp->lock, flags);
|
||||
mask = rnp->wakemask;
|
||||
rnp->wakemask = 0;
|
||||
@ -1661,6 +1669,7 @@ static int rcu_node_kthread(void *arg)
|
||||
preempt_enable();
|
||||
}
|
||||
}
|
||||
rnp->node_kthread_status = RCU_KTHREAD_STOPPED;
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
@ -89,6 +89,13 @@ struct rcu_dynticks {
|
||||
atomic_t dynticks; /* Even value for dynticks-idle, else odd. */
|
||||
};
|
||||
|
||||
/* RCU's kthread states for tracing. */
|
||||
#define RCU_KTHREAD_STOPPED 0
|
||||
#define RCU_KTHREAD_RUNNING 1
|
||||
#define RCU_KTHREAD_WAITING 2
|
||||
#define RCU_KTHREAD_YIELDING 3
|
||||
#define RCU_KTHREAD_MAX 3
|
||||
|
||||
/*
|
||||
* Definition for node within the RCU grace-period-detection hierarchy.
|
||||
*/
|
||||
@ -152,6 +159,8 @@ struct rcu_node {
|
||||
wait_queue_head_t boost_wq;
|
||||
/* Wait queue on which to park the boost */
|
||||
/* kthread. */
|
||||
unsigned int boost_kthread_status;
|
||||
/* State of boost_kthread_task for tracing. */
|
||||
unsigned long n_tasks_boosted;
|
||||
/* Total number of tasks boosted. */
|
||||
unsigned long n_exp_boosts;
|
||||
@ -179,6 +188,8 @@ struct rcu_node {
|
||||
wait_queue_head_t node_wq;
|
||||
/* Wait queue on which to park the per-node */
|
||||
/* kthread. */
|
||||
unsigned int node_kthread_status;
|
||||
/* State of node_kthread_task for tracing. */
|
||||
} ____cacheline_internodealigned_in_smp;
|
||||
|
||||
/*
|
||||
|
||||
@ -1198,11 +1198,13 @@ static int rcu_boost_kthread(void *arg)
|
||||
int more2boost;
|
||||
|
||||
for (;;) {
|
||||
rnp->boost_kthread_status = RCU_KTHREAD_WAITING;
|
||||
wait_event_interruptible(rnp->boost_wq, rnp->boost_tasks ||
|
||||
rnp->exp_tasks ||
|
||||
kthread_should_stop());
|
||||
if (kthread_should_stop())
|
||||
break;
|
||||
rnp->boost_kthread_status = RCU_KTHREAD_RUNNING;
|
||||
more2boost = rcu_boost(rnp);
|
||||
if (more2boost)
|
||||
spincnt++;
|
||||
@ -1213,6 +1215,7 @@ static int rcu_boost_kthread(void *arg)
|
||||
spincnt = 0;
|
||||
}
|
||||
}
|
||||
rnp->boost_kthread_status = RCU_KTHREAD_STOPPED;
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
@ -46,6 +46,16 @@
|
||||
#define RCU_TREE_NONCORE
|
||||
#include "rcutree.h"
|
||||
|
||||
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
|
||||
DECLARE_PER_CPU(char, rcu_cpu_has_work);
|
||||
|
||||
static char convert_kthread_status(unsigned int kthread_status)
|
||||
{
|
||||
if (kthread_status > RCU_KTHREAD_MAX)
|
||||
return '?';
|
||||
return "SRWY"[kthread_status];
|
||||
}
|
||||
|
||||
static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
|
||||
{
|
||||
if (!rdp->beenonline)
|
||||
@ -64,7 +74,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
|
||||
rdp->dynticks_fqs);
|
||||
#endif /* #ifdef CONFIG_NO_HZ */
|
||||
seq_printf(m, " of=%lu ri=%lu", rdp->offline_fqs, rdp->resched_ipi);
|
||||
seq_printf(m, " ql=%ld qs=%c%c%c%c b=%ld",
|
||||
seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c b=%ld",
|
||||
rdp->qlen,
|
||||
".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
|
||||
rdp->nxttail[RCU_NEXT_TAIL]],
|
||||
@ -73,6 +83,9 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
|
||||
".W"[rdp->nxttail[RCU_DONE_TAIL] !=
|
||||
rdp->nxttail[RCU_WAIT_TAIL]],
|
||||
".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
|
||||
per_cpu(rcu_cpu_has_work, rdp->cpu),
|
||||
convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
|
||||
rdp->cpu)),
|
||||
rdp->blimit);
|
||||
seq_printf(m, " ci=%lu co=%lu ca=%lu\n",
|
||||
rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
|
||||
@ -130,7 +143,7 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
|
||||
rdp->dynticks_fqs);
|
||||
#endif /* #ifdef CONFIG_NO_HZ */
|
||||
seq_printf(m, ",%lu,%lu", rdp->offline_fqs, rdp->resched_ipi);
|
||||
seq_printf(m, ",%ld,\"%c%c%c%c\",%ld", rdp->qlen,
|
||||
seq_printf(m, ",%ld,\"%c%c%c%c\",%d,\"%c\",%ld", rdp->qlen,
|
||||
".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
|
||||
rdp->nxttail[RCU_NEXT_TAIL]],
|
||||
".R"[rdp->nxttail[RCU_WAIT_TAIL] !=
|
||||
@ -138,6 +151,9 @@ static void print_one_rcu_data_csv(struct seq_file *m, struct rcu_data *rdp)
|
||||
".W"[rdp->nxttail[RCU_DONE_TAIL] !=
|
||||
rdp->nxttail[RCU_WAIT_TAIL]],
|
||||
".D"[&rdp->nxtlist != rdp->nxttail[RCU_DONE_TAIL]],
|
||||
per_cpu(rcu_cpu_has_work, rdp->cpu),
|
||||
convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
|
||||
rdp->cpu)),
|
||||
rdp->blimit);
|
||||
seq_printf(m, ",%lu,%lu,%lu\n",
|
||||
rdp->n_cbs_invoked, rdp->n_cbs_orphaned, rdp->n_cbs_adopted);
|
||||
@ -178,13 +194,14 @@ static const struct file_operations rcudata_csv_fops = {
|
||||
|
||||
static void print_one_rcu_node_boost(struct seq_file *m, struct rcu_node *rnp)
|
||||
{
|
||||
seq_printf(m, "%d:%d tasks=%c%c%c%c ntb=%lu neb=%lu nnb=%lu "
|
||||
seq_printf(m, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu "
|
||||
"j=%04x bt=%04x\n",
|
||||
rnp->grplo, rnp->grphi,
|
||||
"T."[list_empty(&rnp->blkd_tasks)],
|
||||
"N."[!rnp->gp_tasks],
|
||||
"E."[!rnp->exp_tasks],
|
||||
"B."[!rnp->boost_tasks],
|
||||
convert_kthread_status(rnp->boost_kthread_status),
|
||||
rnp->n_tasks_boosted, rnp->n_exp_boosts,
|
||||
rnp->n_normal_boosts,
|
||||
(int)(jiffies & 0xffff),
|
||||
|
||||
Loading…
Reference in New Issue
Block a user