mm: more likely reclaim MADV_SEQUENTIAL mappings
[linux-2.6.git] / kernel / rcupreempt_trace.c
1 /*
2  * Read-Copy Update tracing for realtime implementation
3  *
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.
8  *
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.
13  *
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.
17  *
18  * Copyright IBM Corporation, 2006
19  *
20  * Papers:  http://www.rdrop.com/users/paulmck/RCU
21  *
22  * For detailed explanation of Read-Copy Update mechanism see -
23  *              Documentation/RCU/ *.txt
24  *
25  */
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 <asm/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/rcupreempt_trace.h>
44 #include <linux/debugfs.h>
45
46 static struct mutex rcupreempt_trace_mutex;
47 static char *rcupreempt_trace_buf;
48 #define RCUPREEMPT_TRACE_BUF_SIZE 4096
49
50 void rcupreempt_trace_move2done(struct rcupreempt_trace *trace)
51 {
52         trace->done_length += trace->wait_length;
53         trace->done_add += trace->wait_length;
54         trace->wait_length = 0;
55 }
56 void rcupreempt_trace_move2wait(struct rcupreempt_trace *trace)
57 {
58         trace->wait_length += trace->next_length;
59         trace->wait_add += trace->next_length;
60         trace->next_length = 0;
61 }
62 void rcupreempt_trace_try_flip_1(struct rcupreempt_trace *trace)
63 {
64         atomic_inc(&trace->rcu_try_flip_1);
65 }
66 void rcupreempt_trace_try_flip_e1(struct rcupreempt_trace *trace)
67 {
68         atomic_inc(&trace->rcu_try_flip_e1);
69 }
70 void rcupreempt_trace_try_flip_i1(struct rcupreempt_trace *trace)
71 {
72         trace->rcu_try_flip_i1++;
73 }
74 void rcupreempt_trace_try_flip_ie1(struct rcupreempt_trace *trace)
75 {
76         trace->rcu_try_flip_ie1++;
77 }
78 void rcupreempt_trace_try_flip_g1(struct rcupreempt_trace *trace)
79 {
80         trace->rcu_try_flip_g1++;
81 }
82 void rcupreempt_trace_try_flip_a1(struct rcupreempt_trace *trace)
83 {
84         trace->rcu_try_flip_a1++;
85 }
86 void rcupreempt_trace_try_flip_ae1(struct rcupreempt_trace *trace)
87 {
88         trace->rcu_try_flip_ae1++;
89 }
90 void rcupreempt_trace_try_flip_a2(struct rcupreempt_trace *trace)
91 {
92         trace->rcu_try_flip_a2++;
93 }
94 void rcupreempt_trace_try_flip_z1(struct rcupreempt_trace *trace)
95 {
96         trace->rcu_try_flip_z1++;
97 }
98 void rcupreempt_trace_try_flip_ze1(struct rcupreempt_trace *trace)
99 {
100         trace->rcu_try_flip_ze1++;
101 }
102 void rcupreempt_trace_try_flip_z2(struct rcupreempt_trace *trace)
103 {
104         trace->rcu_try_flip_z2++;
105 }
106 void rcupreempt_trace_try_flip_m1(struct rcupreempt_trace *trace)
107 {
108         trace->rcu_try_flip_m1++;
109 }
110 void rcupreempt_trace_try_flip_me1(struct rcupreempt_trace *trace)
111 {
112         trace->rcu_try_flip_me1++;
113 }
114 void rcupreempt_trace_try_flip_m2(struct rcupreempt_trace *trace)
115 {
116         trace->rcu_try_flip_m2++;
117 }
118 void rcupreempt_trace_check_callbacks(struct rcupreempt_trace *trace)
119 {
120         trace->rcu_check_callbacks++;
121 }
122 void rcupreempt_trace_done_remove(struct rcupreempt_trace *trace)
123 {
124         trace->done_remove += trace->done_length;
125         trace->done_length = 0;
126 }
127 void rcupreempt_trace_invoke(struct rcupreempt_trace *trace)
128 {
129         atomic_inc(&trace->done_invoked);
130 }
131 void rcupreempt_trace_next_add(struct rcupreempt_trace *trace)
132 {
133         trace->next_add++;
134         trace->next_length++;
135 }
136
137 static void rcupreempt_trace_sum(struct rcupreempt_trace *sp)
138 {
139         struct rcupreempt_trace *cp;
140         int cpu;
141
142         memset(sp, 0, sizeof(*sp));
143         for_each_possible_cpu(cpu) {
144                 cp = rcupreempt_trace_cpu(cpu);
145                 sp->next_length += cp->next_length;
146                 sp->next_add += cp->next_add;
147                 sp->wait_length += cp->wait_length;
148                 sp->wait_add += cp->wait_add;
149                 sp->done_length += cp->done_length;
150                 sp->done_add += cp->done_add;
151                 sp->done_remove += cp->done_remove;
152                 atomic_add(atomic_read(&cp->done_invoked), &sp->done_invoked);
153                 sp->rcu_check_callbacks += cp->rcu_check_callbacks;
154                 atomic_add(atomic_read(&cp->rcu_try_flip_1),
155                            &sp->rcu_try_flip_1);
156                 atomic_add(atomic_read(&cp->rcu_try_flip_e1),
157                            &sp->rcu_try_flip_e1);
158                 sp->rcu_try_flip_i1 += cp->rcu_try_flip_i1;
159                 sp->rcu_try_flip_ie1 += cp->rcu_try_flip_ie1;
160                 sp->rcu_try_flip_g1 += cp->rcu_try_flip_g1;
161                 sp->rcu_try_flip_a1 += cp->rcu_try_flip_a1;
162                 sp->rcu_try_flip_ae1 += cp->rcu_try_flip_ae1;
163                 sp->rcu_try_flip_a2 += cp->rcu_try_flip_a2;
164                 sp->rcu_try_flip_z1 += cp->rcu_try_flip_z1;
165                 sp->rcu_try_flip_ze1 += cp->rcu_try_flip_ze1;
166                 sp->rcu_try_flip_z2 += cp->rcu_try_flip_z2;
167                 sp->rcu_try_flip_m1 += cp->rcu_try_flip_m1;
168                 sp->rcu_try_flip_me1 += cp->rcu_try_flip_me1;
169                 sp->rcu_try_flip_m2 += cp->rcu_try_flip_m2;
170         }
171 }
172
173 static ssize_t rcustats_read(struct file *filp, char __user *buffer,
174                                 size_t count, loff_t *ppos)
175 {
176         struct rcupreempt_trace trace;
177         ssize_t bcount;
178         int cnt = 0;
179
180         rcupreempt_trace_sum(&trace);
181         mutex_lock(&rcupreempt_trace_mutex);
182         snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE - cnt,
183                  "ggp=%ld rcc=%ld\n",
184                  rcu_batches_completed(),
185                  trace.rcu_check_callbacks);
186         snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE - cnt,
187                  "na=%ld nl=%ld wa=%ld wl=%ld da=%ld dl=%ld dr=%ld di=%d\n"
188                  "1=%d e1=%d i1=%ld ie1=%ld g1=%ld a1=%ld ae1=%ld a2=%ld\n"
189                  "z1=%ld ze1=%ld z2=%ld m1=%ld me1=%ld m2=%ld\n",
190
191                  trace.next_add, trace.next_length,
192                  trace.wait_add, trace.wait_length,
193                  trace.done_add, trace.done_length,
194                  trace.done_remove, atomic_read(&trace.done_invoked),
195                  atomic_read(&trace.rcu_try_flip_1),
196                  atomic_read(&trace.rcu_try_flip_e1),
197                  trace.rcu_try_flip_i1, trace.rcu_try_flip_ie1,
198                  trace.rcu_try_flip_g1,
199                  trace.rcu_try_flip_a1, trace.rcu_try_flip_ae1,
200                          trace.rcu_try_flip_a2,
201                  trace.rcu_try_flip_z1, trace.rcu_try_flip_ze1,
202                          trace.rcu_try_flip_z2,
203                  trace.rcu_try_flip_m1, trace.rcu_try_flip_me1,
204                         trace.rcu_try_flip_m2);
205         bcount = simple_read_from_buffer(buffer, count, ppos,
206                         rcupreempt_trace_buf, strlen(rcupreempt_trace_buf));
207         mutex_unlock(&rcupreempt_trace_mutex);
208         return bcount;
209 }
210
211 static ssize_t rcugp_read(struct file *filp, char __user *buffer,
212                                 size_t count, loff_t *ppos)
213 {
214         long oldgp = rcu_batches_completed();
215         ssize_t bcount;
216
217         mutex_lock(&rcupreempt_trace_mutex);
218         synchronize_rcu();
219         snprintf(rcupreempt_trace_buf, RCUPREEMPT_TRACE_BUF_SIZE,
220                 "oldggp=%ld  newggp=%ld\n", oldgp, rcu_batches_completed());
221         bcount = simple_read_from_buffer(buffer, count, ppos,
222                         rcupreempt_trace_buf, strlen(rcupreempt_trace_buf));
223         mutex_unlock(&rcupreempt_trace_mutex);
224         return bcount;
225 }
226
227 static ssize_t rcuctrs_read(struct file *filp, char __user *buffer,
228                                 size_t count, loff_t *ppos)
229 {
230         int cnt = 0;
231         int cpu;
232         int f = rcu_batches_completed() & 0x1;
233         ssize_t bcount;
234
235         mutex_lock(&rcupreempt_trace_mutex);
236
237         cnt += snprintf(&rcupreempt_trace_buf[cnt], RCUPREEMPT_TRACE_BUF_SIZE,
238                                 "CPU last cur F M\n");
239         for_each_online_cpu(cpu) {
240                 long *flipctr = rcupreempt_flipctr(cpu);
241                 cnt += snprintf(&rcupreempt_trace_buf[cnt],
242                                 RCUPREEMPT_TRACE_BUF_SIZE - cnt,
243                                         "%3d %4ld %3ld %d %d\n",
244                                cpu,
245                                flipctr[!f],
246                                flipctr[f],
247                                rcupreempt_flip_flag(cpu),
248                                rcupreempt_mb_flag(cpu));
249         }
250         cnt += snprintf(&rcupreempt_trace_buf[cnt],
251                         RCUPREEMPT_TRACE_BUF_SIZE - cnt,
252                         "ggp = %ld, state = %s\n",
253                         rcu_batches_completed(),
254                         rcupreempt_try_flip_state_name());
255         cnt += snprintf(&rcupreempt_trace_buf[cnt],
256                         RCUPREEMPT_TRACE_BUF_SIZE - cnt,
257                         "\n");
258         bcount = simple_read_from_buffer(buffer, count, ppos,
259                         rcupreempt_trace_buf, strlen(rcupreempt_trace_buf));
260         mutex_unlock(&rcupreempt_trace_mutex);
261         return bcount;
262 }
263
264 static struct file_operations rcustats_fops = {
265         .owner = THIS_MODULE,
266         .read = rcustats_read,
267 };
268
269 static struct file_operations rcugp_fops = {
270         .owner = THIS_MODULE,
271         .read = rcugp_read,
272 };
273
274 static struct file_operations rcuctrs_fops = {
275         .owner = THIS_MODULE,
276         .read = rcuctrs_read,
277 };
278
279 static struct dentry *rcudir, *statdir, *ctrsdir, *gpdir;
280 static int rcupreempt_debugfs_init(void)
281 {
282         rcudir = debugfs_create_dir("rcu", NULL);
283         if (!rcudir)
284                 goto out;
285         statdir = debugfs_create_file("rcustats", 0444, rcudir,
286                                                 NULL, &rcustats_fops);
287         if (!statdir)
288                 goto free_out;
289
290         gpdir = debugfs_create_file("rcugp", 0444, rcudir, NULL, &rcugp_fops);
291         if (!gpdir)
292                 goto free_out;
293
294         ctrsdir = debugfs_create_file("rcuctrs", 0444, rcudir,
295                                                 NULL, &rcuctrs_fops);
296         if (!ctrsdir)
297                 goto free_out;
298         return 0;
299 free_out:
300         if (statdir)
301                 debugfs_remove(statdir);
302         if (gpdir)
303                 debugfs_remove(gpdir);
304         debugfs_remove(rcudir);
305 out:
306         return 1;
307 }
308
309 static int __init rcupreempt_trace_init(void)
310 {
311         int ret;
312
313         mutex_init(&rcupreempt_trace_mutex);
314         rcupreempt_trace_buf = kmalloc(RCUPREEMPT_TRACE_BUF_SIZE, GFP_KERNEL);
315         if (!rcupreempt_trace_buf)
316                 return 1;
317         ret = rcupreempt_debugfs_init();
318         if (ret)
319                 kfree(rcupreempt_trace_buf);
320         return ret;
321 }
322
323 static void __exit rcupreempt_trace_cleanup(void)
324 {
325         debugfs_remove(statdir);
326         debugfs_remove(gpdir);
327         debugfs_remove(ctrsdir);
328         debugfs_remove(rcudir);
329         kfree(rcupreempt_trace_buf);
330 }
331
332
333 module_init(rcupreempt_trace_init);
334 module_exit(rcupreempt_trace_cleanup);