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[Qemu-devel] [PATCH v4 30/32] migration: delay the postcopy-active state
From: |
Peter Xu |
Subject: |
[Qemu-devel] [PATCH v4 30/32] migration: delay the postcopy-active state switch |
Date: |
Wed, 8 Nov 2017 14:01:28 +0800 |
Switch the state until we try to start the VM on destination side. The
problem is that without doing this we may have a very small window that
we'll be in such a state:
- dst VM is in postcopy-active state,
- main thread is handling MIG_CMD_PACKAGED message, which loads all the
device states,
- ram load thread is reading memory data from source.
Then if we failed at this point when reading the migration stream we'll
also switch to postcopy-paused state, but that is not what we want. If
device states failed to load, we should fail the migration directly
instead of pause.
Postponing the state switch to the point when we have already loaded the
devices' states and been ready to start running destination VM.
Signed-off-by: Peter Xu <address@hidden>
---
migration/savevm.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/migration/savevm.c b/migration/savevm.c
index bc87b0e5b1..3bc792e320 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1584,8 +1584,6 @@ static void *postcopy_ram_listen_thread(void *opaque)
QEMUFile *f = mis->from_src_file;
int load_res;
- migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
- MIGRATION_STATUS_POSTCOPY_ACTIVE);
qemu_sem_post(&mis->listen_thread_sem);
trace_postcopy_ram_listen_thread_start();
@@ -1748,6 +1746,14 @@ static int
loadvm_postcopy_handle_run(MigrationIncomingState *mis)
return -1;
}
+ /*
+ * Declare that we are in postcopy now. We should already have
+ * all the device states loaded ready when reach here, and also
+ * the ram load thread running.
+ */
+ migrate_set_state(&mis->state, MIGRATION_STATUS_ACTIVE,
+ MIGRATION_STATUS_POSTCOPY_ACTIVE);
+
data = g_new(HandleRunBhData, 1);
data->bh = qemu_bh_new(loadvm_postcopy_handle_run_bh, data);
qemu_bh_schedule(data->bh);
--
2.13.6
- [Qemu-devel] [PATCH v4 17/32] migration: new cmd MIG_CMD_POSTCOPY_RESUME, (continued)
- [Qemu-devel] [PATCH v4 17/32] migration: new cmd MIG_CMD_POSTCOPY_RESUME, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 18/32] migration: new message MIG_RP_MSG_RESUME_ACK, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 19/32] migration: introduce SaveVMHandlers.resume_prepare, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 20/32] migration: synchronize dirty bitmap for resume, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 21/32] migration: setup ramstate for resume, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 23/32] migration: free SocketAddress where allocated, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 22/32] migration: final handshake for the resume, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 26/32] migration: return incoming task tag for fd, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 27/32] migration: store listen task tag, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 29/32] migration: init dst in migration_object_init too, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 30/32] migration: delay the postcopy-active state switch,
Peter Xu <=
- [Qemu-devel] [PATCH v4 32/32] migration, hmp: new command "migrate_pause", Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 31/32] migration, qmp: new command "migrate-pause", Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 24/32] migration: return incoming task tag for sockets, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 25/32] migration: return incoming task tag for exec, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 14/32] migration: wakeup dst ram-load-thread for recover, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 05/32] migration: implement "postcopy-pause" src logic, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 07/32] migration: allow src return path to pause, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 12/32] migration: rebuild channel on source, Peter Xu, 2017/11/08
- [Qemu-devel] [PATCH v4 13/32] migration: new state "postcopy-recover", Peter Xu, 2017/11/08