qemu/migration.c
Matthew Garrett 40596834c0 migration: Fix rate limit
The migration thread appears to want to allow writeout to occur at full
speed rather than being rate limited during completion of state saving,
but sets the limit to INT_MAX when xfer_limit is INT64_MAX. This causes
problems if there's more than 2GB of state left to save at this point. It
probably ought to just be INT64_MAX instead.

Signed-off-by: Matthew Garrett <matthew.garrett@nebula.com>
Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
2014-01-13 12:39:48 +01:00

684 lines
19 KiB
C

/*
* QEMU live migration
*
* Copyright IBM, Corp. 2008
*
* Authors:
* Anthony Liguori <aliguori@us.ibm.com>
*
* This work is licensed under the terms of the GNU GPL, version 2. See
* the COPYING file in the top-level directory.
*
* Contributions after 2012-01-13 are licensed under the terms of the
* GNU GPL, version 2 or (at your option) any later version.
*/
#include "qemu-common.h"
#include "qemu/main-loop.h"
#include "migration/migration.h"
#include "monitor/monitor.h"
#include "migration/qemu-file.h"
#include "sysemu/sysemu.h"
#include "block/block.h"
#include "qemu/sockets.h"
#include "migration/block.h"
#include "qemu/thread.h"
#include "qmp-commands.h"
#include "trace.h"
//#define DEBUG_MIGRATION
#ifdef DEBUG_MIGRATION
#define DPRINTF(fmt, ...) \
do { printf("migration: " fmt, ## __VA_ARGS__); } while (0)
#else
#define DPRINTF(fmt, ...) \
do { } while (0)
#endif
enum {
MIG_STATE_ERROR = -1,
MIG_STATE_NONE,
MIG_STATE_SETUP,
MIG_STATE_CANCELLING,
MIG_STATE_CANCELLED,
MIG_STATE_ACTIVE,
MIG_STATE_COMPLETED,
};
#define MAX_THROTTLE (32 << 20) /* Migration speed throttling */
/* Amount of time to allocate to each "chunk" of bandwidth-throttled
* data. */
#define BUFFER_DELAY 100
#define XFER_LIMIT_RATIO (1000 / BUFFER_DELAY)
/* Migration XBZRLE default cache size */
#define DEFAULT_MIGRATE_CACHE_SIZE (64 * 1024 * 1024)
static NotifierList migration_state_notifiers =
NOTIFIER_LIST_INITIALIZER(migration_state_notifiers);
/* When we add fault tolerance, we could have several
migrations at once. For now we don't need to add
dynamic creation of migration */
MigrationState *migrate_get_current(void)
{
static MigrationState current_migration = {
.state = MIG_STATE_NONE,
.bandwidth_limit = MAX_THROTTLE,
.xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
.mbps = -1,
};
return &current_migration;
}
void qemu_start_incoming_migration(const char *uri, Error **errp)
{
const char *p;
if (strstart(uri, "tcp:", &p))
tcp_start_incoming_migration(p, errp);
#ifdef CONFIG_RDMA
else if (strstart(uri, "x-rdma:", &p))
rdma_start_incoming_migration(p, errp);
#endif
#if !defined(WIN32)
else if (strstart(uri, "exec:", &p))
exec_start_incoming_migration(p, errp);
else if (strstart(uri, "unix:", &p))
unix_start_incoming_migration(p, errp);
else if (strstart(uri, "fd:", &p))
fd_start_incoming_migration(p, errp);
#endif
else {
error_setg(errp, "unknown migration protocol: %s", uri);
}
}
static void process_incoming_migration_co(void *opaque)
{
QEMUFile *f = opaque;
int ret;
ret = qemu_loadvm_state(f);
qemu_fclose(f);
if (ret < 0) {
fprintf(stderr, "load of migration failed\n");
exit(EXIT_FAILURE);
}
qemu_announce_self();
DPRINTF("successfully loaded vm state\n");
bdrv_clear_incoming_migration_all();
/* Make sure all file formats flush their mutable metadata */
bdrv_invalidate_cache_all();
if (autostart) {
vm_start();
} else {
runstate_set(RUN_STATE_PAUSED);
}
}
void process_incoming_migration(QEMUFile *f)
{
Coroutine *co = qemu_coroutine_create(process_incoming_migration_co);
int fd = qemu_get_fd(f);
assert(fd != -1);
qemu_set_nonblock(fd);
qemu_coroutine_enter(co, f);
}
/* amount of nanoseconds we are willing to wait for migration to be down.
* the choice of nanoseconds is because it is the maximum resolution that
* get_clock() can achieve. It is an internal measure. All user-visible
* units must be in seconds */
static uint64_t max_downtime = 30000000;
uint64_t migrate_max_downtime(void)
{
return max_downtime;
}
MigrationCapabilityStatusList *qmp_query_migrate_capabilities(Error **errp)
{
MigrationCapabilityStatusList *head = NULL;
MigrationCapabilityStatusList *caps;
MigrationState *s = migrate_get_current();
int i;
caps = NULL; /* silence compiler warning */
for (i = 0; i < MIGRATION_CAPABILITY_MAX; i++) {
if (head == NULL) {
head = g_malloc0(sizeof(*caps));
caps = head;
} else {
caps->next = g_malloc0(sizeof(*caps));
caps = caps->next;
}
caps->value =
g_malloc(sizeof(*caps->value));
caps->value->capability = i;
caps->value->state = s->enabled_capabilities[i];
}
return head;
}
static void get_xbzrle_cache_stats(MigrationInfo *info)
{
if (migrate_use_xbzrle()) {
info->has_xbzrle_cache = true;
info->xbzrle_cache = g_malloc0(sizeof(*info->xbzrle_cache));
info->xbzrle_cache->cache_size = migrate_xbzrle_cache_size();
info->xbzrle_cache->bytes = xbzrle_mig_bytes_transferred();
info->xbzrle_cache->pages = xbzrle_mig_pages_transferred();
info->xbzrle_cache->cache_miss = xbzrle_mig_pages_cache_miss();
info->xbzrle_cache->overflow = xbzrle_mig_pages_overflow();
}
}
MigrationInfo *qmp_query_migrate(Error **errp)
{
MigrationInfo *info = g_malloc0(sizeof(*info));
MigrationState *s = migrate_get_current();
switch (s->state) {
case MIG_STATE_NONE:
/* no migration has happened ever */
break;
case MIG_STATE_SETUP:
info->has_status = true;
info->status = g_strdup("setup");
info->has_total_time = false;
break;
case MIG_STATE_ACTIVE:
case MIG_STATE_CANCELLING:
info->has_status = true;
info->status = g_strdup("active");
info->has_total_time = true;
info->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME)
- s->total_time;
info->has_expected_downtime = true;
info->expected_downtime = s->expected_downtime;
info->has_setup_time = true;
info->setup_time = s->setup_time;
info->has_ram = true;
info->ram = g_malloc0(sizeof(*info->ram));
info->ram->transferred = ram_bytes_transferred();
info->ram->remaining = ram_bytes_remaining();
info->ram->total = ram_bytes_total();
info->ram->duplicate = dup_mig_pages_transferred();
info->ram->skipped = skipped_mig_pages_transferred();
info->ram->normal = norm_mig_pages_transferred();
info->ram->normal_bytes = norm_mig_bytes_transferred();
info->ram->dirty_pages_rate = s->dirty_pages_rate;
info->ram->mbps = s->mbps;
if (blk_mig_active()) {
info->has_disk = true;
info->disk = g_malloc0(sizeof(*info->disk));
info->disk->transferred = blk_mig_bytes_transferred();
info->disk->remaining = blk_mig_bytes_remaining();
info->disk->total = blk_mig_bytes_total();
}
get_xbzrle_cache_stats(info);
break;
case MIG_STATE_COMPLETED:
get_xbzrle_cache_stats(info);
info->has_status = true;
info->status = g_strdup("completed");
info->has_total_time = true;
info->total_time = s->total_time;
info->has_downtime = true;
info->downtime = s->downtime;
info->has_setup_time = true;
info->setup_time = s->setup_time;
info->has_ram = true;
info->ram = g_malloc0(sizeof(*info->ram));
info->ram->transferred = ram_bytes_transferred();
info->ram->remaining = 0;
info->ram->total = ram_bytes_total();
info->ram->duplicate = dup_mig_pages_transferred();
info->ram->skipped = skipped_mig_pages_transferred();
info->ram->normal = norm_mig_pages_transferred();
info->ram->normal_bytes = norm_mig_bytes_transferred();
info->ram->mbps = s->mbps;
break;
case MIG_STATE_ERROR:
info->has_status = true;
info->status = g_strdup("failed");
break;
case MIG_STATE_CANCELLED:
info->has_status = true;
info->status = g_strdup("cancelled");
break;
}
return info;
}
void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
Error **errp)
{
MigrationState *s = migrate_get_current();
MigrationCapabilityStatusList *cap;
if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
error_set(errp, QERR_MIGRATION_ACTIVE);
return;
}
for (cap = params; cap; cap = cap->next) {
s->enabled_capabilities[cap->value->capability] = cap->value->state;
}
}
/* shared migration helpers */
static void migrate_set_state(MigrationState *s, int old_state, int new_state)
{
if (atomic_cmpxchg(&s->state, old_state, new_state) == new_state) {
trace_migrate_set_state(new_state);
}
}
static void migrate_fd_cleanup(void *opaque)
{
MigrationState *s = opaque;
qemu_bh_delete(s->cleanup_bh);
s->cleanup_bh = NULL;
if (s->file) {
DPRINTF("closing file\n");
qemu_mutex_unlock_iothread();
qemu_thread_join(&s->thread);
qemu_mutex_lock_iothread();
qemu_fclose(s->file);
s->file = NULL;
}
assert(s->state != MIG_STATE_ACTIVE);
if (s->state != MIG_STATE_COMPLETED) {
qemu_savevm_state_cancel();
if (s->state == MIG_STATE_CANCELLING) {
migrate_set_state(s, MIG_STATE_CANCELLING, MIG_STATE_CANCELLED);
}
}
notifier_list_notify(&migration_state_notifiers, s);
}
void migrate_fd_error(MigrationState *s)
{
DPRINTF("setting error state\n");
assert(s->file == NULL);
s->state = MIG_STATE_ERROR;
trace_migrate_set_state(MIG_STATE_ERROR);
notifier_list_notify(&migration_state_notifiers, s);
}
static void migrate_fd_cancel(MigrationState *s)
{
int old_state ;
DPRINTF("cancelling migration\n");
do {
old_state = s->state;
if (old_state != MIG_STATE_SETUP && old_state != MIG_STATE_ACTIVE) {
break;
}
migrate_set_state(s, old_state, MIG_STATE_CANCELLING);
} while (s->state != MIG_STATE_CANCELLING);
}
void add_migration_state_change_notifier(Notifier *notify)
{
notifier_list_add(&migration_state_notifiers, notify);
}
void remove_migration_state_change_notifier(Notifier *notify)
{
notifier_remove(notify);
}
bool migration_in_setup(MigrationState *s)
{
return s->state == MIG_STATE_SETUP;
}
bool migration_has_finished(MigrationState *s)
{
return s->state == MIG_STATE_COMPLETED;
}
bool migration_has_failed(MigrationState *s)
{
return (s->state == MIG_STATE_CANCELLED ||
s->state == MIG_STATE_ERROR);
}
static MigrationState *migrate_init(const MigrationParams *params)
{
MigrationState *s = migrate_get_current();
int64_t bandwidth_limit = s->bandwidth_limit;
bool enabled_capabilities[MIGRATION_CAPABILITY_MAX];
int64_t xbzrle_cache_size = s->xbzrle_cache_size;
memcpy(enabled_capabilities, s->enabled_capabilities,
sizeof(enabled_capabilities));
memset(s, 0, sizeof(*s));
s->params = *params;
memcpy(s->enabled_capabilities, enabled_capabilities,
sizeof(enabled_capabilities));
s->xbzrle_cache_size = xbzrle_cache_size;
s->bandwidth_limit = bandwidth_limit;
s->state = MIG_STATE_SETUP;
trace_migrate_set_state(MIG_STATE_SETUP);
s->total_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
return s;
}
static GSList *migration_blockers;
void migrate_add_blocker(Error *reason)
{
migration_blockers = g_slist_prepend(migration_blockers, reason);
}
void migrate_del_blocker(Error *reason)
{
migration_blockers = g_slist_remove(migration_blockers, reason);
}
void qmp_migrate(const char *uri, bool has_blk, bool blk,
bool has_inc, bool inc, bool has_detach, bool detach,
Error **errp)
{
Error *local_err = NULL;
MigrationState *s = migrate_get_current();
MigrationParams params;
const char *p;
params.blk = has_blk && blk;
params.shared = has_inc && inc;
if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP ||
s->state == MIG_STATE_CANCELLING) {
error_set(errp, QERR_MIGRATION_ACTIVE);
return;
}
if (qemu_savevm_state_blocked(errp)) {
return;
}
if (migration_blockers) {
*errp = error_copy(migration_blockers->data);
return;
}
s = migrate_init(&params);
if (strstart(uri, "tcp:", &p)) {
tcp_start_outgoing_migration(s, p, &local_err);
#ifdef CONFIG_RDMA
} else if (strstart(uri, "x-rdma:", &p)) {
rdma_start_outgoing_migration(s, p, &local_err);
#endif
#if !defined(WIN32)
} else if (strstart(uri, "exec:", &p)) {
exec_start_outgoing_migration(s, p, &local_err);
} else if (strstart(uri, "unix:", &p)) {
unix_start_outgoing_migration(s, p, &local_err);
} else if (strstart(uri, "fd:", &p)) {
fd_start_outgoing_migration(s, p, &local_err);
#endif
} else {
error_set(errp, QERR_INVALID_PARAMETER_VALUE, "uri", "a valid migration protocol");
return;
}
if (local_err) {
migrate_fd_error(s);
error_propagate(errp, local_err);
return;
}
}
void qmp_migrate_cancel(Error **errp)
{
migrate_fd_cancel(migrate_get_current());
}
void qmp_migrate_set_cache_size(int64_t value, Error **errp)
{
MigrationState *s = migrate_get_current();
/* Check for truncation */
if (value != (size_t)value) {
error_set(errp, QERR_INVALID_PARAMETER_VALUE, "cache size",
"exceeding address space");
return;
}
s->xbzrle_cache_size = xbzrle_cache_resize(value);
}
int64_t qmp_query_migrate_cache_size(Error **errp)
{
return migrate_xbzrle_cache_size();
}
void qmp_migrate_set_speed(int64_t value, Error **errp)
{
MigrationState *s;
if (value < 0) {
value = 0;
}
if (value > SIZE_MAX) {
value = SIZE_MAX;
}
s = migrate_get_current();
s->bandwidth_limit = value;
if (s->file) {
qemu_file_set_rate_limit(s->file, s->bandwidth_limit / XFER_LIMIT_RATIO);
}
}
void qmp_migrate_set_downtime(double value, Error **errp)
{
value *= 1e9;
value = MAX(0, MIN(UINT64_MAX, value));
max_downtime = (uint64_t)value;
}
bool migrate_rdma_pin_all(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_X_RDMA_PIN_ALL];
}
bool migrate_auto_converge(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_AUTO_CONVERGE];
}
bool migrate_zero_blocks(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_ZERO_BLOCKS];
}
int migrate_use_xbzrle(void)
{
MigrationState *s;
s = migrate_get_current();
return s->enabled_capabilities[MIGRATION_CAPABILITY_XBZRLE];
}
int64_t migrate_xbzrle_cache_size(void)
{
MigrationState *s;
s = migrate_get_current();
return s->xbzrle_cache_size;
}
/* migration thread support */
static void *migration_thread(void *opaque)
{
MigrationState *s = opaque;
int64_t initial_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
int64_t initial_bytes = 0;
int64_t max_size = 0;
int64_t start_time = initial_time;
bool old_vm_running = false;
DPRINTF("beginning savevm\n");
qemu_savevm_state_begin(s->file, &s->params);
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);
DPRINTF("setup complete\n");
while (s->state == MIG_STATE_ACTIVE) {
int64_t current_time;
uint64_t pending_size;
if (!qemu_file_rate_limit(s->file)) {
DPRINTF("iterate\n");
pending_size = qemu_savevm_state_pending(s->file, max_size);
DPRINTF("pending size %" PRIu64 " max %" PRIu64 "\n",
pending_size, max_size);
if (pending_size && pending_size >= max_size) {
qemu_savevm_state_iterate(s->file);
} else {
int ret;
DPRINTF("done iterating\n");
qemu_mutex_lock_iothread();
start_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
qemu_system_wakeup_request(QEMU_WAKEUP_REASON_OTHER);
old_vm_running = runstate_is_running();
ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
if (ret >= 0) {
qemu_file_set_rate_limit(s->file, INT64_MAX);
qemu_savevm_state_complete(s->file);
}
qemu_mutex_unlock_iothread();
if (ret < 0) {
migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
break;
}
if (!qemu_file_get_error(s->file)) {
migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_COMPLETED);
break;
}
}
}
if (qemu_file_get_error(s->file)) {
migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
break;
}
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
if (current_time >= initial_time + BUFFER_DELAY) {
uint64_t transferred_bytes = qemu_ftell(s->file) - initial_bytes;
uint64_t time_spent = current_time - initial_time;
double bandwidth = transferred_bytes / time_spent;
max_size = bandwidth * migrate_max_downtime() / 1000000;
s->mbps = time_spent ? (((double) transferred_bytes * 8.0) /
((double) time_spent / 1000.0)) / 1000.0 / 1000.0 : -1;
DPRINTF("transferred %" PRIu64 " time_spent %" PRIu64
" bandwidth %g max_size %" PRId64 "\n",
transferred_bytes, time_spent, bandwidth, max_size);
/* if we haven't sent anything, we don't want to recalculate
10000 is a small enough number for our purposes */
if (s->dirty_bytes_rate && transferred_bytes > 10000) {
s->expected_downtime = s->dirty_bytes_rate / bandwidth;
}
qemu_file_reset_rate_limit(s->file);
initial_time = current_time;
initial_bytes = qemu_ftell(s->file);
}
if (qemu_file_rate_limit(s->file)) {
/* usleep expects microseconds */
g_usleep((initial_time + BUFFER_DELAY - current_time)*1000);
}
}
qemu_mutex_lock_iothread();
if (s->state == MIG_STATE_COMPLETED) {
int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
s->total_time = end_time - s->total_time;
s->downtime = end_time - start_time;
runstate_set(RUN_STATE_POSTMIGRATE);
} else {
if (old_vm_running) {
vm_start();
}
}
qemu_bh_schedule(s->cleanup_bh);
qemu_mutex_unlock_iothread();
return NULL;
}
void migrate_fd_connect(MigrationState *s)
{
s->state = MIG_STATE_SETUP;
trace_migrate_set_state(MIG_STATE_SETUP);
/* This is a best 1st approximation. ns to ms */
s->expected_downtime = max_downtime/1000000;
s->cleanup_bh = qemu_bh_new(migrate_fd_cleanup, s);
qemu_file_set_rate_limit(s->file,
s->bandwidth_limit / XFER_LIMIT_RATIO);
/* Notify before starting migration thread */
notifier_list_notify(&migration_state_notifiers, s);
qemu_thread_create(&s->thread, migration_thread, s,
QEMU_THREAD_JOINABLE);
}