migration.c

   1 /*
   2  * QEMU live migration
   3  *
   4  * Copyright IBM, Corp. 2008
   5  *
   6  * Authors:
   7  *  Anthony Liguori   <aliguori@us.ibm.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  */
  13
  14 #include "qemu-common.h"
  15 #include "migration.h"
  16 #include "monitor.h"
  17 #include "buffered_file.h"
  18 #include "sysemu.h"
  19 #include "block.h"
  20 #include "qemu_socket.h"
  21
  22 //#define DEBUG_MIGRATION
  23
  24 #ifdef DEBUG_MIGRATION
  25 #define dprintf(fmt, ...) \
  26     do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
  27 #else
  28 #define dprintf(fmt, ...) \
  29     do { } while (0)
  30 #endif
  31
  32 /* Migration speed throttling */
  33 static uint32_t max_throttle = (32 << 20);
  34
  35 static MigrationState *current_migration;
  36
  37 void qemu_start_incoming_migration(const char *uri)
  38 {
  39     const char *p;
  40
  41     if (strstart(uri, "tcp:", &p))
  42         tcp_start_incoming_migration(p);
  43 #if !defined(WIN32)
  44     else if (strstart(uri, "exec:", &p))
  45         exec_start_incoming_migration(p);
  46     else if (strstart(uri, "unix:", &p))
  47         unix_start_incoming_migration(p);
  48 #endif
  49     else
  50         fprintf(stderr, "unknown migration protocol: %s\n", uri);
  51 }
  52
  53 void do_migrate(Monitor *mon, int detach, const char *uri)
  54 {
  55     MigrationState *s = NULL;
  56     const char *p;
  57
  58     if (strstart(uri, "tcp:", &p))
  59         s = tcp_start_outgoing_migration(p, max_throttle, detach);
  60 #if !defined(WIN32)
  61     else if (strstart(uri, "exec:", &p))
  62         s = exec_start_outgoing_migration(p, max_throttle, detach);
  63     else if (strstart(uri, "unix:", &p))
  64         s = unix_start_outgoing_migration(p, max_throttle, detach);
  65 #endif
  66     else
  67         monitor_printf(mon, "unknown migration protocol: %s\n", uri);
  68
  69     if (s == NULL)
  70         monitor_printf(mon, "migration failed\n");
  71     else {
  72         if (current_migration)
  73             current_migration->release(current_migration);
  74
  75         current_migration = s;
  76     }
  77 }
  78
  79 void do_migrate_cancel(Monitor *mon)
  80 {
  81     MigrationState *s = current_migration;
  82
  83     if (s)
  84         s->cancel(s);
  85 }
  86
  87 void do_migrate_set_speed(Monitor *mon, const char *value)
  88 {
  89     double d;
  90     char *ptr;
  91     FdMigrationState *s;
  92
  93     d = strtod(value, &ptr);
  94     switch (*ptr) {
  95     case 'G': case 'g':
  96         d *= 1024;
  97     case 'M': case 'm':
  98         d *= 1024;
  99     case 'K': case 'k':
 100         d *= 1024;
 101     default:
 102         break;
 103     }
 104
 105     max_throttle = (uint32_t)d;
 106     s = migrate_to_fms(current_migration);
 107
 108     if (s) {
 109         qemu_file_set_rate_limit(s->file, max_throttle);
 110     }
 111
 112 }
 113
 114 /* amount of nanoseconds we are willing to wait for migration to be down.
 115  * the choice of nanoseconds is because it is the maximum resolution that
 116  * get_clock() can achieve. It is an internal measure. All user-visible
 117  * units must be in seconds */
 118 static uint64_t max_downtime = 30000000;
 119
 120 uint64_t migrate_max_downtime(void)
 121 {
 122     return max_downtime;
 123 }
 124
 125 void do_migrate_set_downtime(Monitor *mon, const char *value)
 126 {
 127     char *ptr;
 128     double d;
 129
 130     d = strtod(value, &ptr);
 131     if (!strcmp(ptr,"ms")) {
 132         d *= 1000000;
 133     } else if (!strcmp(ptr,"us")) {
 134         d *= 1000;
 135     } else if (!strcmp(ptr,"ns")) {
 136     } else {
 137         /* all else considered to be seconds */
 138         d *= 1000000000;
 139     }
 140
 141     max_downtime = (uint64_t)d;
 142 }
 143
 144 void do_info_migrate(Monitor *mon)
 145 {
 146     MigrationState *s = current_migration;
 147
 148     if (s) {
 149         monitor_printf(mon, "Migration status: ");
 150         switch (s->get_status(s)) {
 151         case MIG_STATE_ACTIVE:
 152             monitor_printf(mon, "active\n");
 153             monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n", ram_bytes_transferred() >> 10);
 154             monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n", ram_bytes_remaining() >> 10);
 155             monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n", ram_bytes_total() >> 10);
 156             break;
 157         case MIG_STATE_COMPLETED:
 158             monitor_printf(mon, "completed\n");
 159             break;
 160         case MIG_STATE_ERROR:
 161             monitor_printf(mon, "failed\n");
 162             break;
 163         case MIG_STATE_CANCELLED:
 164             monitor_printf(mon, "cancelled\n");
 165             break;
 166         }
 167     }
 168 }
 169
 170 /* shared migration helpers */
 171
 172 void migrate_fd_monitor_suspend(FdMigrationState *s)
 173 {
 174     s->mon_resume = cur_mon;
 175     if (monitor_suspend(cur_mon) == 0)
 176         dprintf("suspending monitor\n");
 177     else
 178         monitor_printf(cur_mon, "terminal does not allow synchronous "
 179                        "migration, continuing detached\n");
 180 }
 181
 182 void migrate_fd_error(FdMigrationState *s)
 183 {
 184     dprintf("setting error state\n");
 185     s->state = MIG_STATE_ERROR;
 186     migrate_fd_cleanup(s);
 187 }
 188
 189 void migrate_fd_cleanup(FdMigrationState *s)
 190 {
 191     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 192
 193     if (s->file) {
 194         dprintf("closing file\n");
 195         qemu_fclose(s->file);
 196     }
 197
 198     if (s->fd != -1)
 199         close(s->fd);
 200
 201     /* Don't resume monitor until we've flushed all of the buffers */
 202     if (s->mon_resume)
 203         monitor_resume(s->mon_resume);
 204
 205     s->fd = -1;
 206 }
 207
 208 void migrate_fd_put_notify(void *opaque)
 209 {
 210     FdMigrationState *s = opaque;
 211
 212     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 213     qemu_file_put_notify(s->file);
 214 }
 215
 216 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 217 {
 218     FdMigrationState *s = opaque;
 219     ssize_t ret;
 220
 221     do {
 222         ret = s->write(s, data, size);
 223     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 224
 225     if (ret == -1)
 226         ret = -(s->get_error(s));
 227
 228     if (ret == -EAGAIN)
 229         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 230
 231     return ret;
 232 }
 233
 234 void migrate_fd_connect(FdMigrationState *s)
 235 {
 236     int ret;
 237
 238     s->file = qemu_fopen_ops_buffered(s,
 239                                       s->bandwidth_limit,
 240                                       migrate_fd_put_buffer,
 241                                       migrate_fd_put_ready,
 242                                       migrate_fd_wait_for_unfreeze,
 243                                       migrate_fd_close);
 244
 245     dprintf("beginning savevm\n");
 246     ret = qemu_savevm_state_begin(s->file);
 247     if (ret < 0) {
 248         dprintf("failed, %d\n", ret);
 249         migrate_fd_error(s);
 250         return;
 251     }
 252
 253     migrate_fd_put_ready(s);
 254 }
 255
 256 void migrate_fd_put_ready(void *opaque)
 257 {
 258     FdMigrationState *s = opaque;
 259
 260     if (s->state != MIG_STATE_ACTIVE) {
 261         dprintf("put_ready returning because of non-active state\n");
 262         return;
 263     }
 264
 265     dprintf("iterate\n");
 266     if (qemu_savevm_state_iterate(s->file) == 1) {
 267         int state;
 268         int old_vm_running = vm_running;
 269
 270         dprintf("done iterating\n");
 271         vm_stop(0);
 272
 273         qemu_aio_flush();
 274         bdrv_flush_all();
 275         if ((qemu_savevm_state_complete(s->file)) < 0) {
 276             if (old_vm_running) {
 277                 vm_start();
 278             }
 279             state = MIG_STATE_ERROR;
 280         } else {
 281             state = MIG_STATE_COMPLETED;
 282         }
 283         migrate_fd_cleanup(s);
 284         s->state = state;
 285     }
 286 }
 287
 288 int migrate_fd_get_status(MigrationState *mig_state)
 289 {
 290     FdMigrationState *s = migrate_to_fms(mig_state);
 291     return s->state;
 292 }
 293
 294 void migrate_fd_cancel(MigrationState *mig_state)
 295 {
 296     FdMigrationState *s = migrate_to_fms(mig_state);
 297
 298     if (s->state != MIG_STATE_ACTIVE)
 299         return;
 300
 301     dprintf("cancelling migration\n");
 302
 303     s->state = MIG_STATE_CANCELLED;
 304
 305     migrate_fd_cleanup(s);
 306 }
 307
 308 void migrate_fd_release(MigrationState *mig_state)
 309 {
 310     FdMigrationState *s = migrate_to_fms(mig_state);
 311
 312     dprintf("releasing state\n");
 313
 314     if (s->state == MIG_STATE_ACTIVE) {
 315         s->state = MIG_STATE_CANCELLED;
 316         migrate_fd_cleanup(s);
 317     }
 318     free(s);
 319 }
 320
 321 void migrate_fd_wait_for_unfreeze(void *opaque)
 322 {
 323     FdMigrationState *s = opaque;
 324     int ret;
 325
 326     dprintf("wait for unfreeze\n");
 327     if (s->state != MIG_STATE_ACTIVE)
 328         return;
 329
 330     do {
 331         fd_set wfds;
 332
 333         FD_ZERO(&wfds);
 334         FD_SET(s->fd, &wfds);
 335
 336         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 337     } while (ret == -1 && (s->get_error(s)) == EINTR);
 338 }
 339
 340 int migrate_fd_close(void *opaque)
 341 {
 342     FdMigrationState *s = opaque;
 343
 344     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 345     return s->close(s);
 346 }