From: "Dr. David Alan Gilbert" <dgilb...@redhat.com>
Rework the migration thread to setup and start postcopy.
Signed-off-by: Dr. David Alan Gilbert <dgilb...@redhat.com>
---
include/migration/migration.h | 3 +
migration.c | 201 ++++++++++++++++++++++++++++++++++++++----
2 files changed, 185 insertions(+), 19 deletions(-)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index b01cc17..f401775 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -125,6 +125,9 @@ struct MigrationState
/* Flag set once the migration has been asked to enter postcopy */
volatile bool start_postcopy;
+ /* Flag set once the migration thread is running (and needs joining) */
+ volatile bool started_migration_thread;
+
/* bitmap of pages that have been sent at least once
* only maintained and used in postcopy at the moment
* where it's used to send the dirtymap at the start
diff --git a/migration.c b/migration.c
index 63d70b6..1731017 100644
--- a/migration.c
+++ b/migration.c
@@ -475,7 +475,10 @@ static void migrate_fd_cleanup(void *opaque)
if (s->file) {
trace_migrate_fd_cleanup();
qemu_mutex_unlock_iothread();
- qemu_thread_join(&s->thread);
+ if (s->started_migration_thread) {
+ qemu_thread_join(&s->thread);
+ s->started_migration_thread = false;
+ }
qemu_mutex_lock_iothread();
qemu_fclose(s->file);
@@ -872,7 +875,6 @@ out:
return NULL;
}
-__attribute__ (( unused )) /* Until later in patch series */
static int open_outgoing_return_path(MigrationState *ms)
{
@@ -890,7 +892,6 @@ static int open_outgoing_return_path(MigrationState *ms)
return 0;
}
-__attribute__ (( unused )) /* Until later in patch series */
static void await_outgoing_return_path_close(MigrationState *ms)
{
/*
@@ -908,6 +909,97 @@ static void
await_outgoing_return_path_close(MigrationState *ms)
DPRINTF("%s: Exit", __func__);
}
+/* Switch from normal iteration to postcopy
+ * Returns non-0 on error
+ */
+static int postcopy_start(MigrationState *ms)
+{
+ int ret;
+ const QEMUSizedBuffer *qsb;
+ migrate_set_state(ms, MIG_STATE_ACTIVE, MIG_STATE_POSTCOPY_ACTIVE);
+
+ DPRINTF("postcopy_start\n");
+ qemu_mutex_lock_iothread();
+ DPRINTF("postcopy_start: setting run state\n");
+ ret = vm_stop_force_state(RUN_STATE_FINISH_MIGRATE);
+
+ if (ret < 0) {
+ migrate_set_state(ms, MIG_STATE_POSTCOPY_ACTIVE, MIG_STATE_ERROR);
+ qemu_mutex_unlock_iothread();
+ return -1;
+ }
+
+ /*
+ * in Finish migrate and with the io-lock held everything should
+ * be quiet, but we've potentially still got dirty pages and we
+ * need to tell the destination to throw any pages it's already received
+ * that are dirty
+ */
+ if (ram_postcopy_send_discard_bitmap(ms)) {
+ DPRINTF("postcopy send discard bitmap failed\n");
+ migrate_set_state(ms, MIG_STATE_POSTCOPY_ACTIVE, MIG_STATE_ERROR);
+ qemu_mutex_unlock_iothread();
+ return -1;
+ }
+
+ DPRINTF("postcopy_start: sending req 2\n");
+ qemu_savevm_send_reqack(ms->file, 2);
+ /*
+ * send rest of state - note things that are doing postcopy
+ * will notice we're in MIG_STATE_POSTCOPY_ACTIVE and not actually
+ * wrap their state up here
+ */
+ qemu_file_set_rate_limit(ms->file, INT64_MAX);
+ DPRINTF("postcopy_start: do state_complete\n");
+
+ /*
+ * We need to leave the fd free for page transfers during the
+ * loading of the device state, so wrap all the remaining
+ * commands and state into a package that gets sent in one go
+ */
+ QEMUFile *fb = qemu_bufopen("w", NULL);
+ if (!fb) {
+ error_report("Failed to create buffered file");
+ migrate_set_state(ms, MIG_STATE_POSTCOPY_ACTIVE, MIG_STATE_ERROR);
+ qemu_mutex_unlock_iothread();
+ return -1;
+ }
+
+ qemu_savevm_state_complete(fb);
+ DPRINTF("postcopy_start: sending req 3\n");
+ qemu_savevm_send_reqack(fb, 3);
+
+ qemu_savevm_send_postcopy_ram_run(fb);
+
+ /* <><> end of stuff going into the package */
+ qsb = qemu_buf_get(fb);
+
+ /* Now send that blob */
+ if (qsb_get_length(qsb) > MAX_VM_CMD_PACKAGED_SIZE) {
+ DPRINTF("postcopy_start: Unreasonably large packaged state: %lu\n",
+ (unsigned long)(qsb_get_length(qsb)));
+ migrate_set_state(ms, MIG_STATE_POSTCOPY_ACTIVE, MIG_STATE_ERROR);
+ qemu_mutex_unlock_iothread();
+ qemu_fclose(fb);
+ return -1;
+ }
+ qemu_savevm_send_packaged(ms->file, qsb);
+ qemu_fclose(fb);
+
+ qemu_mutex_unlock_iothread();
+
+ DPRINTF("postcopy_start not finished sending ack\n");
+ qemu_savevm_send_reqack(ms->file, 4);
+
+ ret = qemu_file_get_error(ms->file);
+ if (ret) {
+ error_report("postcopy_start: Migration stream errored");
+ migrate_set_state(ms, MIG_STATE_POSTCOPY_ACTIVE, MIG_STATE_ERROR);
+ }
+
+ return ret;
+}
+
/*
* Master migration thread on the source VM.
* It drives the migration and pumps the data down the outgoing channel.
@@ -915,16 +1007,36 @@ static void
await_outgoing_return_path_close(MigrationState *ms)
static void *migration_thread(void *opaque)
{
MigrationState *s = opaque;
+ /* Used by the bandwidth calcs, updated later */
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;
+ /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */
+ enum MigrationPhase current_active_type = MIG_STATE_ACTIVE;
+
qemu_savevm_state_begin(s->file, &s->params);
+ if (migrate_postcopy_ram()) {
+ /* Now tell the dest that it should open it's end so it can reply */
+ qemu_savevm_send_openrp(s->file);
+
+ /* And ask it to send an ack that will make stuff easier to debug */
+ qemu_savevm_send_reqack(s->file, 1);
+
+ /* Tell the destination that we *might* want to do postcopy later;
+ * if the other end can't do postcopy it should fail now, nice and
+ * early.
+ */
+ qemu_savevm_send_postcopy_ram_advise(s->file);
+ }
+
s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
+ current_active_type = MIG_STATE_ACTIVE;
migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);
DPRINTF("setup complete\n");
@@ -945,37 +1057,74 @@ static void *migration_thread(void *opaque)
" nonpost=%" PRIu64 ")\n",
pending_size, max_size, pend_post, pend_nonpost);
if (pending_size && pending_size >= max_size) {
+ /* Still a significant amount to transfer */
+
+ current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ if (migrate_postcopy_ram() &&
+ s->state != MIG_STATE_POSTCOPY_ACTIVE &&
+ pend_nonpost == 0 && s->start_postcopy) {
+
+ if (!postcopy_start(s)) {
+ current_active_type = MIG_STATE_POSTCOPY_ACTIVE;
+ }
+
+ continue;
+ }
+ /* Just another iteration step */
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();
+ DPRINTF("done iterating pending size %" PRIu64 "\n",
+ pending_size);
+
+ if (s->state == MIG_STATE_ACTIVE) {
+ 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, current_active_type,
+ MIG_STATE_ERROR);
+ break;
+ }
+ } else if (s->state == MIG_STATE_POSTCOPY_ACTIVE) {
+ DPRINTF("postcopy end\n");
+
+ qemu_savevm_state_postcopy_complete(s->file);
+ DPRINTF("postcopy end after complete\n");
- 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 rp was opened we must clean up the thread before
+ * cleaning everything else up.
+ * Postcopy opens rp if enabled (even if it's not avtivated)
+ */
+ if (migrate_postcopy_ram()) {
+ DPRINTF("before rp close");
+ await_outgoing_return_path_close(s);
+ DPRINTF("after rp close");
}
-
if (!qemu_file_get_error(s->file)) {
- migrate_set_state(s, MIG_STATE_ACTIVE,
MIG_STATE_COMPLETED);
+ migrate_set_state(s, current_active_type,
+ MIG_STATE_COMPLETED);
break;
}
}
}
if (qemu_file_get_error(s->file)) {
- migrate_set_state(s, MIG_STATE_ACTIVE, MIG_STATE_ERROR);
+ migrate_set_state(s, current_active_type, MIG_STATE_ERROR);
+ DPRINTF("migration_thread: file is in error state\n");
break;
}
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
@@ -1006,6 +1155,7 @@ static void *migration_thread(void *opaque)
}
}
+ DPRINTF("migration_thread: After loop");
qemu_mutex_lock_iothread();
if (s->state == MIG_STATE_COMPLETED) {
int64_t end_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
@@ -1043,6 +1193,19 @@ void migrate_fd_connect(MigrationState *s)
/* Notify before starting migration thread */
notifier_list_notify(&migration_state_notifiers, s);
+ /* Open the return path; currently for postcopy but other things might
+ * also want it.
+ */
+ if (migrate_postcopy_ram()) {
+ if (open_outgoing_return_path(s)) {
+ error_report("Unable to open return-path for postcopy");
+ migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ERROR);
+ migrate_fd_cleanup(s);
+ return;
+ }
+ }
+
qemu_thread_create(&s->thread, "migration", migration_thread, s,
QEMU_THREAD_JOINABLE);
+ s->started_migration_thread = true;
}
--
1.9.3
