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_info_migrate(Monitor *mon)
 122 {
 123     MigrationState *s = current_migration;
 124
 125     if (s) {
 126         monitor_printf(mon, "Migration status: ");
 127         switch (s->get_status(s)) {
 128         case MIG_STATE_ACTIVE:
 129             monitor_printf(mon, "active\n");
 130             monitor_printf(mon, "transferred ram: %" PRIu64 " kbytes\n", ram_bytes_transferred() >> 10);
 131             monitor_printf(mon, "remaining ram: %" PRIu64 " kbytes\n", ram_bytes_remaining() >> 10);
 132             monitor_printf(mon, "total ram: %" PRIu64 " kbytes\n", ram_bytes_total() >> 10);
 133             break;
 134         case MIG_STATE_COMPLETED:
 135             monitor_printf(mon, "completed\n");
 136             break;
 137         case MIG_STATE_ERROR:
 138             monitor_printf(mon, "failed\n");
 139             break;
 140         case MIG_STATE_CANCELLED:
 141             monitor_printf(mon, "cancelled\n");
 142             break;
 143         }
 144     }
 145 }
 146
 147 /* shared migration helpers */
 148
 149 void migrate_fd_monitor_suspend(FdMigrationState *s)
 150 {
 151     s->mon_resume = cur_mon;
 152     if (monitor_suspend(cur_mon) == 0)
 153         dprintf("suspending monitor\n");
 154     else
 155         monitor_printf(cur_mon, "terminal does not allow synchronous "
 156                        "migration, continuing detached\n");
 157 }
 158
 159 void migrate_fd_error(FdMigrationState *s)
 160 {
 161     dprintf("setting error state\n");
 162     s->state = MIG_STATE_ERROR;
 163     migrate_fd_cleanup(s);
 164 }
 165
 166 void migrate_fd_cleanup(FdMigrationState *s)
 167 {
 168     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 169
 170     if (s->file) {
 171         dprintf("closing file\n");
 172         qemu_fclose(s->file);
 173     }
 174
 175     if (s->fd != -1)
 176         close(s->fd);
 177
 178     /* Don't resume monitor until we've flushed all of the buffers */
 179     if (s->mon_resume)
 180         monitor_resume(s->mon_resume);
 181
 182     s->fd = -1;
 183 }
 184
 185 void migrate_fd_put_notify(void *opaque)
 186 {
 187     FdMigrationState *s = opaque;
 188
 189     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 190     qemu_file_put_notify(s->file);
 191 }
 192
 193 ssize_t migrate_fd_put_buffer(void *opaque, const void *data, size_t size)
 194 {
 195     FdMigrationState *s = opaque;
 196     ssize_t ret;
 197
 198     do {
 199         ret = s->write(s, data, size);
 200     } while (ret == -1 && ((s->get_error(s)) == EINTR));
 201
 202     if (ret == -1)
 203         ret = -(s->get_error(s));
 204
 205     if (ret == -EAGAIN)
 206         qemu_set_fd_handler2(s->fd, NULL, NULL, migrate_fd_put_notify, s);
 207
 208     return ret;
 209 }
 210
 211 void migrate_fd_connect(FdMigrationState *s)
 212 {
 213     int ret;
 214
 215     s->file = qemu_fopen_ops_buffered(s,
 216                                       s->bandwidth_limit,
 217                                       migrate_fd_put_buffer,
 218                                       migrate_fd_put_ready,
 219                                       migrate_fd_wait_for_unfreeze,
 220                                       migrate_fd_close);
 221
 222     dprintf("beginning savevm\n");
 223     ret = qemu_savevm_state_begin(s->file);
 224     if (ret < 0) {
 225         dprintf("failed, %d\n", ret);
 226         migrate_fd_error(s);
 227         return;
 228     }
 229
 230     migrate_fd_put_ready(s);
 231 }
 232
 233 void migrate_fd_put_ready(void *opaque)
 234 {
 235     FdMigrationState *s = opaque;
 236
 237     if (s->state != MIG_STATE_ACTIVE) {
 238         dprintf("put_ready returning because of non-active state\n");
 239         return;
 240     }
 241
 242     dprintf("iterate\n");
 243     if (qemu_savevm_state_iterate(s->file) == 1) {
 244         int state;
 245         dprintf("done iterating\n");
 246         vm_stop(0);
 247
 248         bdrv_flush_all();
 249         if ((qemu_savevm_state_complete(s->file)) < 0) {
 250             vm_start();
 251             state = MIG_STATE_ERROR;
 252         } else {
 253             state = MIG_STATE_COMPLETED;
 254         }
 255         migrate_fd_cleanup(s);
 256         s->state = state;
 257     }
 258 }
 259
 260 int migrate_fd_get_status(MigrationState *mig_state)
 261 {
 262     FdMigrationState *s = migrate_to_fms(mig_state);
 263     return s->state;
 264 }
 265
 266 void migrate_fd_cancel(MigrationState *mig_state)
 267 {
 268     FdMigrationState *s = migrate_to_fms(mig_state);
 269
 270     if (s->state != MIG_STATE_ACTIVE)
 271         return;
 272
 273     dprintf("cancelling migration\n");
 274
 275     s->state = MIG_STATE_CANCELLED;
 276
 277     migrate_fd_cleanup(s);
 278 }
 279
 280 void migrate_fd_release(MigrationState *mig_state)
 281 {
 282     FdMigrationState *s = migrate_to_fms(mig_state);
 283
 284     dprintf("releasing state\n");
 285
 286     if (s->state == MIG_STATE_ACTIVE) {
 287         s->state = MIG_STATE_CANCELLED;
 288         migrate_fd_cleanup(s);
 289     }
 290     free(s);
 291 }
 292
 293 void migrate_fd_wait_for_unfreeze(void *opaque)
 294 {
 295     FdMigrationState *s = opaque;
 296     int ret;
 297
 298     dprintf("wait for unfreeze\n");
 299     if (s->state != MIG_STATE_ACTIVE)
 300         return;
 301
 302     do {
 303         fd_set wfds;
 304
 305         FD_ZERO(&wfds);
 306         FD_SET(s->fd, &wfds);
 307
 308         ret = select(s->fd + 1, NULL, &wfds, NULL, NULL);
 309     } while (ret == -1 && (s->get_error(s)) == EINTR);
 310 }
 311
 312 int migrate_fd_close(void *opaque)
 313 {
 314     FdMigrationState *s = opaque;
 315
 316     qemu_set_fd_handler2(s->fd, NULL, NULL, NULL, NULL);
 317     return s->close(s);
 318 }