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