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[Qemu-devel] [PATCH COLO-Frame (Base) v21 06/17] COLO: Introduce checkpo
From: |
zhanghailiang |
Subject: |
[Qemu-devel] [PATCH COLO-Frame (Base) v21 06/17] COLO: Introduce checkpointing protocol |
Date: |
Tue, 18 Oct 2016 20:10:02 +0800 |
We need communications protocol of user-defined to control
the checkpointing process.
The new checkpointing request is started by Primary VM,
and the interactive process like below:
Checkpoint synchronizing points:
Primary Secondary
initial work
'checkpoint-ready' <-------------------- @
'checkpoint-request' @ -------------------->
Suspend (Only in hybrid mode)
'checkpoint-reply' <-------------------- @
Suspend&Save state
'vmstate-send' @ -------------------->
Send state Receive state
'vmstate-received' <-------------------- @
Release packets Load state
'vmstate-load' <-------------------- @
Resume Resume (Only in hybrid mode)
Start Comparing (Only in hybrid mode)
NOTE:
1) '@' who sends the message
2) Every sync-point is synchronized by two sides with only
one handshake(single direction) for low-latency.
If more strict synchronization is required, a opposite direction
sync-point should be added.
3) Since sync-points are single direction, the remote side may
go forward a lot when this side just receives the sync-point.
4) For now, we only support 'periodic' checkpoint, for which
the Secondary VM is not running, later we will support 'hybrid' mode.
Signed-off-by: zhanghailiang <address@hidden>
Signed-off-by: Li Zhijian <address@hidden>
Signed-off-by: Gonglei <address@hidden>
Cc: Eric Blake <address@hidden>
Cc: Markus Armbruster <address@hidden>
Cc: Dr. David Alan Gilbert <address@hidden>
Reviewed-by: Dr. David Alan Gilbert <address@hidden>
---
v19:
- fix title and comments
v16:
- Rename 'colo_put/get[_check]_cmd()' to 'colo_send/receive[_check]_message()'
v14:
- Rename 'COLOCommand' to 'COLOMessage'. (Markus's suggestion)
- Add Reviewd-by tag
v13:
- Refactor colo command related helper functions, use 'Error **errp' parameter
instead of return value to indicate success or failure.
- Fix some other comments from Markus.
v12:
- Rename colo_ctl_put() to colo_put_cmd()
- Rename colo_ctl_get() to colo_get_check_cmd() and drop
the third parameter
- Rename colo_ctl_get_cmd() to colo_get_cmd()
- Remove useless 'invalid' member for COLOcommand enum.
v11:
- Add missing 'checkpoint-ready' communication in comment.
- Use parameter to return 'value' for colo_ctl_get() (Dave's suggestion)
- Fix trace for colo_ctl_get() to trace command and value both
v10:
- Rename enum COLOCmd to COLOCommand (Eric's suggestion).
- Remove unused 'ram-steal'
---
migration/colo.c | 200 ++++++++++++++++++++++++++++++++++++++++++++++++-
migration/trace-events | 2 +
qapi-schema.json | 25 +++++++
3 files changed, 225 insertions(+), 2 deletions(-)
diff --git a/migration/colo.c b/migration/colo.c
index 7c5769b..bf32d63 100644
--- a/migration/colo.c
+++ b/migration/colo.c
@@ -15,6 +15,7 @@
#include "migration/colo.h"
#include "trace.h"
#include "qemu/error-report.h"
+#include "qapi/error.h"
bool colo_supported(void)
{
@@ -35,22 +36,146 @@ bool migration_incoming_in_colo_state(void)
return mis && (mis->state == MIGRATION_STATUS_COLO);
}
+static void colo_send_message(QEMUFile *f, COLOMessage msg,
+ Error **errp)
+{
+ int ret;
+
+ if (msg >= COLO_MESSAGE__MAX) {
+ error_setg(errp, "%s: Invalid message", __func__);
+ return;
+ }
+ qemu_put_be32(f, msg);
+ qemu_fflush(f);
+
+ ret = qemu_file_get_error(f);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Can't send COLO message");
+ }
+ trace_colo_send_message(COLOMessage_lookup[msg]);
+}
+
+static COLOMessage colo_receive_message(QEMUFile *f, Error **errp)
+{
+ COLOMessage msg;
+ int ret;
+
+ msg = qemu_get_be32(f);
+ ret = qemu_file_get_error(f);
+ if (ret < 0) {
+ error_setg_errno(errp, -ret, "Can't receive COLO message");
+ return msg;
+ }
+ if (msg >= COLO_MESSAGE__MAX) {
+ error_setg(errp, "%s: Invalid message", __func__);
+ return msg;
+ }
+ trace_colo_receive_message(COLOMessage_lookup[msg]);
+ return msg;
+}
+
+static void colo_receive_check_message(QEMUFile *f, COLOMessage expect_msg,
+ Error **errp)
+{
+ COLOMessage msg;
+ Error *local_err = NULL;
+
+ msg = colo_receive_message(f, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+ if (msg != expect_msg) {
+ error_setg(errp, "Unexpected COLO message %d, expected %d",
+ msg, expect_msg);
+ }
+}
+
+static int colo_do_checkpoint_transaction(MigrationState *s)
+{
+ Error *local_err = NULL;
+
+ colo_send_message(s->to_dst_file, COLO_MESSAGE_CHECKPOINT_REQUEST,
+ &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ colo_receive_check_message(s->rp_state.from_dst_file,
+ COLO_MESSAGE_CHECKPOINT_REPLY, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ /* TODO: suspend and save vm state to colo buffer */
+
+ colo_send_message(s->to_dst_file, COLO_MESSAGE_VMSTATE_SEND, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ /* TODO: send vmstate to Secondary */
+
+ colo_receive_check_message(s->rp_state.from_dst_file,
+ COLO_MESSAGE_VMSTATE_RECEIVED, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ colo_receive_check_message(s->rp_state.from_dst_file,
+ COLO_MESSAGE_VMSTATE_LOADED, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ /* TODO: resume Primary */
+
+ return 0;
+out:
+ if (local_err) {
+ error_report_err(local_err);
+ }
+ return -EINVAL;
+}
+
static void colo_process_checkpoint(MigrationState *s)
{
+ Error *local_err = NULL;
+ int ret;
+
s->rp_state.from_dst_file = qemu_file_get_return_path(s->to_dst_file);
if (!s->rp_state.from_dst_file) {
error_report("Open QEMUFile from_dst_file failed");
goto out;
}
+ /*
+ * Wait for Secondary finish loading VM states and enter COLO
+ * restore.
+ */
+ colo_receive_check_message(s->rp_state.from_dst_file,
+ COLO_MESSAGE_CHECKPOINT_READY, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
qemu_mutex_lock_iothread();
vm_start();
qemu_mutex_unlock_iothread();
trace_colo_vm_state_change("stop", "run");
- /* TODO: COLO checkpoint savevm loop */
+ while (s->state == MIGRATION_STATUS_COLO) {
+ ret = colo_do_checkpoint_transaction(s);
+ if (ret < 0) {
+ goto out;
+ }
+ }
out:
+ /* Throw the unreported error message after exited from loop */
+ if (local_err) {
+ error_report_err(local_err);
+ }
migrate_set_state(&s->state, MIGRATION_STATUS_COLO,
MIGRATION_STATUS_COMPLETED);
@@ -68,9 +193,33 @@ void migrate_start_colo_process(MigrationState *s)
qemu_mutex_lock_iothread();
}
+static void colo_wait_handle_message(QEMUFile *f, int *checkpoint_request,
+ Error **errp)
+{
+ COLOMessage msg;
+ Error *local_err = NULL;
+
+ msg = colo_receive_message(f, &local_err);
+ if (local_err) {
+ error_propagate(errp, local_err);
+ return;
+ }
+
+ switch (msg) {
+ case COLO_MESSAGE_CHECKPOINT_REQUEST:
+ *checkpoint_request = 1;
+ break;
+ default:
+ *checkpoint_request = 0;
+ error_setg(errp, "Got unknown COLO message: %d", msg);
+ break;
+ }
+}
+
void *colo_process_incoming_thread(void *opaque)
{
MigrationIncomingState *mis = opaque;
+ Error *local_err = NULL;
migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
MIGRATION_STATUS_COLO);
@@ -87,9 +236,56 @@ void *colo_process_incoming_thread(void *opaque)
*/
qemu_file_set_blocking(mis->from_src_file, true);
- /* TODO: COLO checkpoint restore loop */
+ colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_READY,
+ &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ while (mis->state == MIGRATION_STATUS_COLO) {
+ int request;
+
+ colo_wait_handle_message(mis->from_src_file, &request, &local_err);
+ if (local_err) {
+ goto out;
+ }
+ assert(request);
+ /* FIXME: This is unnecessary for periodic checkpoint mode */
+ colo_send_message(mis->to_src_file, COLO_MESSAGE_CHECKPOINT_REPLY,
+ &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ colo_receive_check_message(mis->from_src_file,
+ COLO_MESSAGE_VMSTATE_SEND, &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ /* TODO: read migration data into colo buffer */
+
+ colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_RECEIVED,
+ &local_err);
+ if (local_err) {
+ goto out;
+ }
+
+ /* TODO: load vm state */
+
+ colo_send_message(mis->to_src_file, COLO_MESSAGE_VMSTATE_LOADED,
+ &local_err);
+ if (local_err) {
+ goto out;
+ }
+ }
out:
+ /* Throw the unreported error message after exited from loop */
+ if (local_err) {
+ error_report_err(local_err);
+ }
+
if (mis->to_src_file) {
qemu_fclose(mis->to_src_file);
}
diff --git a/migration/trace-events b/migration/trace-events
index a29e5a0..f374c8c 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -210,3 +210,5 @@ migration_tls_incoming_handshake_complete(void) ""
# migration/colo.c
colo_vm_state_change(const char *old, const char *new) "Change '%s' => '%s'"
+colo_send_message(const char *msg) "Send '%s' message"
+colo_receive_message(const char *msg) "Receive '%s' message"
diff --git a/qapi-schema.json b/qapi-schema.json
index aaed423..276d2cf 100644
--- a/qapi-schema.json
+++ b/qapi-schema.json
@@ -785,6 +785,31 @@
{ 'command': 'migrate-start-postcopy' }
##
+# @COLOMessage
+#
+# The message transmission between PVM and SVM
+#
+# @checkpoint-ready: SVM is ready for checkpointing
+#
+# @checkpoint-request: PVM tells SVM to prepare for new checkpointing
+#
+# @checkpoint-reply: SVM gets PVM's checkpoint request
+#
+# @vmstate-send: VM's state will be sent by PVM.
+#
+# @vmstate-size: The total size of VMstate.
+#
+# @vmstate-received: VM's state has been received by SVM.
+#
+# @vmstate-loaded: VM's state has been loaded by SVM.
+#
+# Since: 2.8
+##
+{ 'enum': 'COLOMessage',
+ 'data': [ 'checkpoint-ready', 'checkpoint-request', 'checkpoint-reply',
+ 'vmstate-send', 'vmstate-size', 'vmstate-received',
+ 'vmstate-loaded' ] }
+
# @MouseInfo:
#
# Information about a mouse device.
--
1.8.3.1
- Re: [Qemu-devel] [PATCH COLO-Frame (Base) v21 17/17] configure: Support enable/disable COLO feature, (continued)
[Qemu-devel] [PATCH COLO-Frame (Base) v21 12/17] COLO: Add 'x-colo-lost-heartbeat' command to trigger failover, zhanghailiang, 2016/10/18
[Qemu-devel] [PATCH COLO-Frame (Base) v21 06/17] COLO: Introduce checkpointing protocol,
zhanghailiang <=
[Qemu-devel] [PATCH COLO-Frame (Base) v21 05/17] COLO: Establish a new communicating path for COLO, zhanghailiang, 2016/10/18
[Qemu-devel] [PATCH COLO-Frame (Base) v21 01/17] migration: Introduce capability 'x-colo' to migration, zhanghailiang, 2016/10/18
[Qemu-devel] [PATCH COLO-Frame (Base) v21 09/17] COLO: Load VMState into QIOChannelBuffer before restore it, zhanghailiang, 2016/10/18