2 * Read-Copy Update tracing for classic implementation
4 * This program is free software; you can redistribute it and/or modify
5 * it under the terms of the GNU General Public License as published by
6 * the Free Software Foundation; either version 2 of the License, or
7 * (at your option) any later version.
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
18 * Copyright IBM Corporation, 2008
20 * Papers: http://www.rdrop.com/users/paulmck/RCU
22 * For detailed explanation of Read-Copy Update mechanism see -
26 #include <linux/types.h>
27 #include <linux/kernel.h>
28 #include <linux/init.h>
29 #include <linux/spinlock.h>
30 #include <linux/smp.h>
31 #include <linux/rcupdate.h>
32 #include <linux/interrupt.h>
33 #include <linux/sched.h>
34 #include <linux/atomic.h>
35 #include <linux/bitops.h>
36 #include <linux/module.h>
37 #include <linux/completion.h>
38 #include <linux/moduleparam.h>
39 #include <linux/percpu.h>
40 #include <linux/notifier.h>
41 #include <linux/cpu.h>
42 #include <linux/mutex.h>
43 #include <linux/debugfs.h>
44 #include <linux/seq_file.h>
46 #define RCU_TREE_NONCORE
49 #define ulong2long(a) (*(long *)(&(a)))
51 static int r_open(struct inode
*inode
, struct file
*file
,
52 const struct seq_operations
*op
)
54 int ret
= seq_open(file
, op
);
56 struct seq_file
*m
= (struct seq_file
*)file
->private_data
;
57 m
->private = inode
->i_private
;
62 static void *r_start(struct seq_file
*m
, loff_t
*pos
)
64 struct rcu_state
*rsp
= (struct rcu_state
*)m
->private;
65 *pos
= cpumask_next(*pos
- 1, cpu_possible_mask
);
66 if ((*pos
) < nr_cpu_ids
)
67 return per_cpu_ptr(rsp
->rda
, *pos
);
71 static void *r_next(struct seq_file
*m
, void *v
, loff_t
*pos
)
74 return r_start(m
, pos
);
77 static void r_stop(struct seq_file
*m
, void *v
)
81 static int show_rcubarrier(struct seq_file
*m
, void *unused
)
83 struct rcu_state
*rsp
;
85 for_each_rcu_flavor(rsp
)
86 seq_printf(m
, "%s: bcc: %d nbd: %lu\n",
88 atomic_read(&rsp
->barrier_cpu_count
),
93 static int rcubarrier_open(struct inode
*inode
, struct file
*file
)
95 return single_open(file
, show_rcubarrier
, NULL
);
98 static const struct file_operations rcubarrier_fops
= {
100 .open
= rcubarrier_open
,
103 .release
= single_release
,
106 static int new_show_rcubarrier(struct seq_file
*m
, void *v
)
108 struct rcu_state
*rsp
= (struct rcu_state
*)m
->private;
109 seq_printf(m
, "bcc: %d nbd: %lu\n",
110 atomic_read(&rsp
->barrier_cpu_count
),
111 rsp
->n_barrier_done
);
115 static int new_rcubarrier_open(struct inode
*inode
, struct file
*file
)
117 return single_open(file
, new_show_rcubarrier
, inode
->i_private
);
120 static const struct file_operations new_rcubarrier_fops
= {
121 .owner
= THIS_MODULE
,
122 .open
= new_rcubarrier_open
,
125 .release
= seq_release
,
128 #ifdef CONFIG_RCU_BOOST
130 static char convert_kthread_status(unsigned int kthread_status
)
132 if (kthread_status
> RCU_KTHREAD_MAX
)
134 return "SRWOY"[kthread_status
];
137 #endif /* #ifdef CONFIG_RCU_BOOST */
139 static void print_one_rcu_data(struct seq_file
*m
, struct rcu_data
*rdp
)
141 if (!rdp
->beenonline
)
143 seq_printf(m
, "%3d%cc=%ld g=%ld pq=%d qp=%d",
145 cpu_is_offline(rdp
->cpu
) ? '!' : ' ',
146 ulong2long(rdp
->completed
), ulong2long(rdp
->gpnum
),
147 rdp
->passed_quiesce
, rdp
->qs_pending
);
148 seq_printf(m
, " dt=%d/%llx/%d df=%lu",
149 atomic_read(&rdp
->dynticks
->dynticks
),
150 rdp
->dynticks
->dynticks_nesting
,
151 rdp
->dynticks
->dynticks_nmi_nesting
,
153 seq_printf(m
, " of=%lu", rdp
->offline_fqs
);
154 seq_printf(m
, " ql=%ld/%ld qs=%c%c%c%c",
155 rdp
->qlen_lazy
, rdp
->qlen
,
156 ".N"[rdp
->nxttail
[RCU_NEXT_READY_TAIL
] !=
157 rdp
->nxttail
[RCU_NEXT_TAIL
]],
158 ".R"[rdp
->nxttail
[RCU_WAIT_TAIL
] !=
159 rdp
->nxttail
[RCU_NEXT_READY_TAIL
]],
160 ".W"[rdp
->nxttail
[RCU_DONE_TAIL
] !=
161 rdp
->nxttail
[RCU_WAIT_TAIL
]],
162 ".D"[&rdp
->nxtlist
!= rdp
->nxttail
[RCU_DONE_TAIL
]]);
163 #ifdef CONFIG_RCU_BOOST
164 seq_printf(m
, " kt=%d/%c ktl=%x",
165 per_cpu(rcu_cpu_has_work
, rdp
->cpu
),
166 convert_kthread_status(per_cpu(rcu_cpu_kthread_status
,
168 per_cpu(rcu_cpu_kthread_loops
, rdp
->cpu
) & 0xffff);
169 #endif /* #ifdef CONFIG_RCU_BOOST */
170 seq_printf(m
, " b=%ld", rdp
->blimit
);
171 seq_printf(m
, " ci=%lu co=%lu ca=%lu\n",
172 rdp
->n_cbs_invoked
, rdp
->n_cbs_orphaned
, rdp
->n_cbs_adopted
);
175 static int show_rcudata(struct seq_file
*m
, void *v
)
177 print_one_rcu_data(m
, (struct rcu_data
*)v
);
181 static const struct seq_operations rcudate_op
= {
185 .show
= show_rcudata
,
188 static int rcudata_open(struct inode
*inode
, struct file
*file
)
190 return r_open(inode
, file
, &rcudate_op
);
193 static const struct file_operations rcudata_fops
= {
194 .owner
= THIS_MODULE
,
195 .open
= rcudata_open
,
198 .release
= seq_release
,
201 #ifdef CONFIG_RCU_BOOST
203 static void print_one_rcu_node_boost(struct seq_file
*m
, struct rcu_node
*rnp
)
205 seq_printf(m
, "%d:%d tasks=%c%c%c%c kt=%c ntb=%lu neb=%lu nnb=%lu ",
206 rnp
->grplo
, rnp
->grphi
,
207 "T."[list_empty(&rnp
->blkd_tasks
)],
208 "N."[!rnp
->gp_tasks
],
209 "E."[!rnp
->exp_tasks
],
210 "B."[!rnp
->boost_tasks
],
211 convert_kthread_status(rnp
->boost_kthread_status
),
212 rnp
->n_tasks_boosted
, rnp
->n_exp_boosts
,
213 rnp
->n_normal_boosts
);
214 seq_printf(m
, "j=%04x bt=%04x\n",
215 (int)(jiffies
& 0xffff),
216 (int)(rnp
->boost_time
& 0xffff));
217 seq_printf(m
, " balk: nt=%lu egt=%lu bt=%lu nb=%lu ny=%lu nos=%lu\n",
218 rnp
->n_balk_blkd_tasks
,
219 rnp
->n_balk_exp_gp_tasks
,
220 rnp
->n_balk_boost_tasks
,
221 rnp
->n_balk_notblocked
,
226 static int show_rcu_node_boost(struct seq_file
*m
, void *unused
)
228 struct rcu_node
*rnp
;
230 rcu_for_each_leaf_node(&rcu_preempt_state
, rnp
)
231 print_one_rcu_node_boost(m
, rnp
);
235 static int rcu_node_boost_open(struct inode
*inode
, struct file
*file
)
237 return single_open(file
, show_rcu_node_boost
, NULL
);
240 static const struct file_operations rcu_node_boost_fops
= {
241 .owner
= THIS_MODULE
,
242 .open
= rcu_node_boost_open
,
245 .release
= single_release
,
249 * Create the rcuboost debugfs entry. Standard error return.
251 static int rcu_boost_trace_create_file(struct dentry
*rcudir
)
253 return !debugfs_create_file("rcuboost", 0444, rcudir
, NULL
,
254 &rcu_node_boost_fops
);
257 #else /* #ifdef CONFIG_RCU_BOOST */
259 static int rcu_boost_trace_create_file(struct dentry
*rcudir
)
261 return 0; /* There cannot be an error if we didn't create it! */
264 #endif /* #else #ifdef CONFIG_RCU_BOOST */
266 static void print_one_rcu_state(struct seq_file
*m
, struct rcu_state
*rsp
)
270 struct rcu_node
*rnp
;
273 seq_printf(m
, "%s: c=%ld g=%ld s=%d jfq=%ld j=%x ",
274 rsp
->name
, ulong2long(rsp
->completed
), ulong2long(gpnum
),
276 (long)(rsp
->jiffies_force_qs
- jiffies
),
277 (int)(jiffies
& 0xffff));
278 seq_printf(m
, "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n",
279 rsp
->n_force_qs
, rsp
->n_force_qs_ngp
,
280 rsp
->n_force_qs
- rsp
->n_force_qs_ngp
,
281 rsp
->n_force_qs_lh
, rsp
->qlen_lazy
, rsp
->qlen
);
282 for (rnp
= &rsp
->node
[0]; rnp
- &rsp
->node
[0] < rcu_num_nodes
; rnp
++) {
283 if (rnp
->level
!= level
) {
287 seq_printf(m
, "%lx/%lx %c%c>%c %d:%d ^%d ",
288 rnp
->qsmask
, rnp
->qsmaskinit
,
289 ".G"[rnp
->gp_tasks
!= NULL
],
290 ".E"[rnp
->exp_tasks
!= NULL
],
291 ".T"[!list_empty(&rnp
->blkd_tasks
)],
292 rnp
->grplo
, rnp
->grphi
, rnp
->grpnum
);
297 static int show_rcuhier(struct seq_file
*m
, void *unused
)
299 struct rcu_state
*rsp
;
301 for_each_rcu_flavor(rsp
)
302 print_one_rcu_state(m
, rsp
);
306 static int rcuhier_open(struct inode
*inode
, struct file
*file
)
308 return single_open(file
, show_rcuhier
, NULL
);
311 static const struct file_operations rcuhier_fops
= {
312 .owner
= THIS_MODULE
,
313 .open
= rcuhier_open
,
316 .release
= single_release
,
319 static void show_one_rcugp(struct seq_file
*m
, struct rcu_state
*rsp
)
322 unsigned long completed
;
326 struct rcu_node
*rnp
= &rsp
->node
[0];
328 raw_spin_lock_irqsave(&rnp
->lock
, flags
);
329 completed
= ACCESS_ONCE(rsp
->completed
);
330 gpnum
= ACCESS_ONCE(rsp
->gpnum
);
331 if (completed
== gpnum
)
334 gpage
= jiffies
- rsp
->gp_start
;
336 raw_spin_unlock_irqrestore(&rnp
->lock
, flags
);
337 seq_printf(m
, "%s: completed=%ld gpnum=%ld age=%ld max=%ld\n",
338 rsp
->name
, ulong2long(completed
), ulong2long(gpnum
), gpage
, gpmax
);
341 static int show_rcugp(struct seq_file
*m
, void *unused
)
343 struct rcu_state
*rsp
;
345 for_each_rcu_flavor(rsp
)
346 show_one_rcugp(m
, rsp
);
350 static int rcugp_open(struct inode
*inode
, struct file
*file
)
352 return single_open(file
, show_rcugp
, NULL
);
355 static const struct file_operations rcugp_fops
= {
356 .owner
= THIS_MODULE
,
360 .release
= single_release
,
363 static void print_one_rcu_pending(struct seq_file
*m
, struct rcu_data
*rdp
)
365 if (!rdp
->beenonline
)
367 seq_printf(m
, "%3d%cnp=%ld ",
369 cpu_is_offline(rdp
->cpu
) ? '!' : ' ',
371 seq_printf(m
, "qsp=%ld rpq=%ld cbr=%ld cng=%ld ",
372 rdp
->n_rp_qs_pending
,
375 rdp
->n_rp_cpu_needs_gp
);
376 seq_printf(m
, "gpc=%ld gps=%ld nn=%ld\n",
377 rdp
->n_rp_gp_completed
,
378 rdp
->n_rp_gp_started
,
379 rdp
->n_rp_need_nothing
);
382 static int show_rcu_pending(struct seq_file
*m
, void *v
)
384 print_one_rcu_pending(m
, (struct rcu_data
*)v
);
388 static const struct seq_operations rcu_pending_op
= {
392 .show
= show_rcu_pending
,
395 static int rcu_pending_open(struct inode
*inode
, struct file
*file
)
397 return r_open(inode
, file
, &rcu_pending_op
);
400 static const struct file_operations rcu_pending_fops
= {
401 .owner
= THIS_MODULE
,
402 .open
= rcu_pending_open
,
405 .release
= seq_release
,
408 static int show_rcutorture(struct seq_file
*m
, void *unused
)
410 seq_printf(m
, "rcutorture test sequence: %lu %s\n",
411 rcutorture_testseq
>> 1,
412 (rcutorture_testseq
& 0x1) ? "(test in progress)" : "");
413 seq_printf(m
, "rcutorture update version number: %lu\n",
418 static int rcutorture_open(struct inode
*inode
, struct file
*file
)
420 return single_open(file
, show_rcutorture
, NULL
);
423 static const struct file_operations rcutorture_fops
= {
424 .owner
= THIS_MODULE
,
425 .open
= rcutorture_open
,
428 .release
= single_release
,
431 static struct dentry
*rcudir
;
433 static int __init
rcutree_trace_init(void)
435 struct rcu_state
*rsp
;
436 struct dentry
*retval
;
437 struct dentry
*rspdir
;
439 rcudir
= debugfs_create_dir("rcu", NULL
);
443 for_each_rcu_flavor(rsp
) {
444 rspdir
= debugfs_create_dir(rsp
->name
, rcudir
);
448 retval
= debugfs_create_file("rcudata", 0444,
449 rspdir
, rsp
, &rcudata_fops
);
453 retval
= debugfs_create_file("rcu_pending", 0444,
454 rspdir
, rsp
, &rcu_pending_fops
);
458 retval
= debugfs_create_file("rcubarrier", 0444,
459 rspdir
, rsp
, &new_rcubarrier_fops
);
464 retval
= debugfs_create_file("rcubarrier", 0444, rcudir
,
465 NULL
, &rcubarrier_fops
);
469 if (rcu_boost_trace_create_file(rcudir
))
472 retval
= debugfs_create_file("rcugp", 0444, rcudir
, NULL
, &rcugp_fops
);
476 retval
= debugfs_create_file("rcuhier", 0444, rcudir
,
477 NULL
, &rcuhier_fops
);
481 retval
= debugfs_create_file("rcutorture", 0444, rcudir
,
482 NULL
, &rcutorture_fops
);
487 debugfs_remove_recursive(rcudir
);
491 static void __exit
rcutree_trace_cleanup(void)
493 debugfs_remove_recursive(rcudir
);
497 module_init(rcutree_trace_init
);
498 module_exit(rcutree_trace_cleanup
);
500 MODULE_AUTHOR("Paul E. McKenney");
501 MODULE_DESCRIPTION("Read-Copy Update tracing for hierarchical implementation");
502 MODULE_LICENSE("GPL");