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