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[Qemu-devel] [PATCH v5 30/45] Postcopy: Postcopy startup in migration th
From: |
Dr. David Alan Gilbert (git) |
Subject: |
[Qemu-devel] [PATCH v5 30/45] Postcopy: Postcopy startup in migration thread |
Date: |
Wed, 25 Feb 2015 16:51:53 +0000 |
From: "Dr. David Alan Gilbert" <address@hidden>
Rework the migration thread to setup and start postcopy.
Signed-off-by: Dr. David Alan Gilbert <address@hidden>
---
include/migration/migration.h | 3 +
migration/migration.c | 161 ++++++++++++++++++++++++++++++++++++++++--
trace-events | 4 ++
3 files changed, 164 insertions(+), 4 deletions(-)
diff --git a/include/migration/migration.h b/include/migration/migration.h
index 821d561..2c607e7 100644
--- a/include/migration/migration.h
+++ b/include/migration/migration.h
@@ -131,6 +131,9 @@ struct MigrationState
/* Flag set once the migration has been asked to enter postcopy */
bool start_postcopy;
+ /* Flag set once the migration thread is running (and needs joining) */
+ 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/migration.c b/migration/migration.c
index b1ad7b1..6bf9c8d 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -468,7 +468,10 @@ 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);
@@ -874,7 +877,6 @@ out:
return NULL;
}
-__attribute__ (( unused )) /* Until later in patch series */
static int open_outgoing_return_path(MigrationState *ms)
{
@@ -911,23 +913,141 @@ static void
await_outgoing_return_path_close(MigrationState *ms)
}
/*
+ * Switch from normal iteration to postcopy
+ * Returns non-0 on error
+ */
+static int postcopy_start(MigrationState *ms, bool *old_vm_running)
+{
+ int ret;
+ const QEMUSizedBuffer *qsb;
+ int64_t time_at_stop = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
+ migrate_set_state(ms, MIG_STATE_ACTIVE, MIG_STATE_POSTCOPY_ACTIVE);
+
+ trace_postcopy_start();
+ qemu_mutex_lock_iothread();
+ trace_postcopy_start_set_run();
+
+ 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) {
+ goto fail;
+ }
+
+ /*
+ * 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)) {
+ error_report("postcopy send discard bitmap failed");
+ goto fail;
+ }
+
+ /*
+ * 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);
+ /* Ping just for debugging, helps line traces up */
+ qemu_savevm_send_ping(ms->file, 2);
+
+ /*
+ * 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");
+ goto fail;
+ }
+
+ qemu_savevm_state_complete(fb);
+ qemu_savevm_send_ping(fb, 3);
+
+ qemu_savevm_send_postcopy_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) {
+ error_report("postcopy_start: Unreasonably large packaged state: %lu",
+ (unsigned long)(qsb_get_length(qsb)));
+ goto fail_closefb;
+ }
+ qemu_savevm_send_packaged(ms->file, qsb);
+ qemu_fclose(fb);
+ ms->downtime = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - time_at_stop;
+
+ qemu_mutex_unlock_iothread();
+
+ /*
+ * Although this ping is just for debug, it could potentially be
+ * used for getting a better measurement of downtime at the source.
+ */
+ qemu_savevm_send_ping(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;
+
+fail_closefb:
+ qemu_fclose(fb);
+fail:
+ migrate_set_state(ms, MIG_STATE_POSTCOPY_ACTIVE, MIG_STATE_ERROR);
+ qemu_mutex_unlock_iothread();
+ return -1;
+}
+
+/*
* Master migration thread on the source VM.
* It drives the migration and pumps the data down the outgoing channel.
*/
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;
+ bool entered_postcopy = false;
+ /* The active state we expect to be in; ACTIVE or POSTCOPY_ACTIVE */
+ enum MigrationPhase current_active_type = MIG_STATE_ACTIVE;
qemu_savevm_state_header(s->file);
+
+ if (migrate_postcopy_ram()) {
+ /* Now tell the dest that it should open its end so it can reply */
+ qemu_savevm_send_open_return_path(s->file);
+
+ /* And do a ping that will make stuff easier to debug */
+ qemu_savevm_send_ping(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_advise(s->file);
+ }
+
qemu_savevm_state_begin(s->file, &s->params);
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);
trace_migration_thread_setup_complete();
@@ -946,6 +1066,22 @@ static void *migration_thread(void *opaque)
trace_migrate_pending(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 <= max_size &&
+ atomic_read(&s->start_postcopy)) {
+
+ if (!postcopy_start(s, &old_vm_running)) {
+ current_active_type = MIG_STATE_POSTCOPY_ACTIVE;
+ entered_postcopy = true;
+ }
+
+ continue;
+ }
+ /* Just another iteration step */
qemu_savevm_state_iterate(s->file);
} else {
int ret;
@@ -975,7 +1111,8 @@ static void *migration_thread(void *opaque)
}
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);
+ trace_migration_thread_file_err();
break;
}
current_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
@@ -1006,12 +1143,15 @@ static void *migration_thread(void *opaque)
}
}
+ trace_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);
uint64_t transferred_bytes = qemu_ftell(s->file);
s->total_time = end_time - s->total_time;
- s->downtime = end_time - start_time;
+ if (!entered_postcopy) {
+ s->downtime = end_time - start_time;
+ }
if (s->total_time) {
s->mbps = (((double) transferred_bytes * 8.0) /
((double) s->total_time)) / 1000;
@@ -1043,8 +1183,21 @@ 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;
}
PostcopyState postcopy_state_get(MigrationIncomingState *mis)
diff --git a/trace-events b/trace-events
index 59dea4c..ed8bbe2 100644
--- a/trace-events
+++ b/trace-events
@@ -1404,9 +1404,13 @@ migrate_fd_error(void) ""
migrate_fd_cancel(void) ""
migrate_pending(uint64_t size, uint64_t max, uint64_t post, uint64_t nonpost)
"pending size %" PRIu64 " max %" PRIu64 " (post=%" PRIu64 " nonpost=%" PRIu64
")"
migrate_send_rp_message(int cmd, uint16_t len) "cmd=%d, len=%d"
+migration_thread_after_loop(void) ""
+migration_thread_file_err(void) ""
migration_thread_setup_complete(void) ""
open_outgoing_return_path(void) ""
open_outgoing_return_path_continue(void) ""
+postcopy_start(void) ""
+postcopy_start_set_run(void) ""
source_return_path_thread_bad_end(void) ""
source_return_path_bad_header_com(void) ""
source_return_path_thread_end(void) ""
--
2.1.0
- [Qemu-devel] [PATCH v5 21/45] Add Linux userfaultfd header, (continued)
- [Qemu-devel] [PATCH v5 21/45] Add Linux userfaultfd header, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 20/45] Modify savevm handlers for postcopy, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 24/45] MIG_STATE_POSTCOPY_ACTIVE: Add new migration state, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 22/45] postcopy: OS support test, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 23/45] migrate_start_postcopy: Command to trigger transition to postcopy, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 25/45] qemu_savevm_state_complete: Postcopy changes, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 26/45] Postcopy page-map-incoming (PMI) structure, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 29/45] postcopy: ram_enable_notify to switch on userfault, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 28/45] postcopy: Incoming initialisation, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 27/45] Postcopy: Maintain sentmap and calculate discard, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 30/45] Postcopy: Postcopy startup in migration thread,
Dr. David Alan Gilbert (git) <=
- [Qemu-devel] [PATCH v5 31/45] Postcopy end in migration_thread, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 32/45] Page request: Add MIG_RP_CMD_REQ_PAGES reverse command, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 33/45] Page request: Process incoming page request, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 34/45] Page request: Consume pages off the post-copy queue, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 35/45] postcopy_ram.c: place_page and helpers, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 36/45] Postcopy: Use helpers to map pages during migration, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 38/45] Don't sync dirty bitmaps in postcopy, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 39/45] Host page!=target page: Cleanup bitmaps, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 37/45] qemu_ram_block_from_host, Dr. David Alan Gilbert (git), 2015/02/25
- [Qemu-devel] [PATCH v5 40/45] Postcopy; Handle userfault requests, Dr. David Alan Gilbert (git), 2015/02/25