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rcu: add grace-period age and more kthread state to tracing

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This commit adds the age in jiffies of the current grace period along
with the duration in jiffies of the longest grace period since boot
to the rcu/rcugp debugfs file.  It also adds an additional "O" state
to kthread tracing to differentiate between the kthread waiting due to
having nothing to do on the one hand and waiting due to being on the
wrong CPU on the other hand.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney
2011-04-06 16:01:16 -07:00
committed by Paul E. McKenney
parent a9f4793d89
commit 15ba0ba860
4 changed files with 54 additions and 12 deletions
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37
kernel/rcutree_trace.c
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@@ -47,13 +47,14 @@
#include "rcutree.h"
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_status);
DECLARE_PER_CPU(unsigned int, rcu_cpu_kthread_cpu);
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];
return "SRWOY"[kthread_status];
}
static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
@@ -74,7 +75,7 @@ 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 kt=%d/%c b=%ld",
seq_printf(m, " ql=%ld qs=%c%c%c%c kt=%d/%c/%d b=%ld",
rdp->qlen,
".N"[rdp->nxttail[RCU_NEXT_READY_TAIL] !=
rdp->nxttail[RCU_NEXT_TAIL]],
@@ -86,6 +87,7 @@ static void print_one_rcu_data(struct seq_file *m, struct rcu_data *rdp)
per_cpu(rcu_cpu_has_work, rdp->cpu),
convert_kthread_status(per_cpu(rcu_cpu_kthread_status,
rdp->cpu)),
per_cpu(rcu_cpu_kthread_cpu, 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);
@@ -312,16 +314,35 @@ static const struct file_operations rcuhier_fops = {
.release = single_release,
};
static void show_one_rcugp(struct seq_file *m, struct rcu_state *rsp)
{
unsigned long flags;
unsigned long completed;
unsigned long gpnum;
unsigned long gpage;
unsigned long gpmax;
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)
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);
}
static int show_rcugp(struct seq_file *m, void *unused)
{
#ifdef CONFIG_TREE_PREEMPT_RCU
seq_printf(m, "rcu_preempt: completed=%ld gpnum=%lu\n",
rcu_preempt_state.completed, rcu_preempt_state.gpnum);
show_one_rcugp(m, &rcu_preempt_state);
#endif /* #ifdef CONFIG_TREE_PREEMPT_RCU */
seq_printf(m, "rcu_sched: completed=%ld gpnum=%lu\n",
rcu_sched_state.completed, rcu_sched_state.gpnum);
seq_printf(m, "rcu_bh: completed=%ld gpnum=%lu\n",
rcu_bh_state.completed, rcu_bh_state.gpnum);
show_one_rcugp(m, &rcu_sched_state);
show_one_rcugp(m, &rcu_bh_state);
return 0;
}