Subject: [PATCH 18/46] rdma: introduce MIG_STATE_NONE and change MIG_STATE_SETUP state transition

From: Nigel Croxon <[email-masked]>
Date: Thu, 14 Nov 2013 22:52:54 +0100

RH-Author: Nigel Croxon <[email-masked]>
Message-id: <[email-masked]>
Patchwork-id: 55699
O-Subject: [RHEL7.0 PATCH 18/42] rdma: introduce MIG_STATE_NONE and change MIG_STATE_SETUP state transition
Bugzilla: 1011720
RH-Acked-by: Orit Wasserman <[email-masked]>
RH-Acked-by: Amit Shah <[email-masked]>
RH-Acked-by: Paolo Bonzini <[email-masked]>

Bugzilla: 1011720
https://bugzilla.redhat.com/show_bug.cgi?id=1011720

>From commit ID:
commit 29ae8a4133082e16970c9d4be09f4b6a15034617
Author: Michael R. Hines <[email-masked]>
Date:   Mon Jul 22 10:01:57 2013 -0400

    rdma: introduce MIG_STATE_NONE and change MIG_STATE_SETUP state transition

    As described in the previous patch, until now, the MIG_STATE_SETUP
    state was not really a 'formal' state. It has been used as a 'zero' state
    (what we're calling 'NONE' here) and QEMU has been unconditionally transitioning
    into this state when the QMP migration command was called. Instead we want to
    introduce MIG_STATE_NONE, which is our starting state in the state machine, and
    then immediately transition into the MIG_STATE_SETUP state when the QMP migrate
    command is issued.

    In order to do this, we must delay the transition into MIG_STATE_ACTIVE until
    later in the migration_thread(). This is done to be able to timestamp the amount of
    time spent in the SETUP state for proper accounting to the user during
    an RDMA migration.

    Furthermore, the management software, until now, has never been aware of the
    existence of the SETUP state whatsoever. This must change, because, timing of this
    state implies that the state actually exists.

    These two patches cannot be separated because the 'query_migrate' QMP
    switch statement needs to know how to handle this new state transition.

    Reviewed-by: Juan Quintela <[email-masked]>
    Tested-by: Michael R. Hines <[email-masked]>
    Signed-off-by: Michael R. Hines <[email-masked]>
    Signed-off-by: Juan Quintela <[email-masked]>
---
 migration.c |   21 ++++++++++++++-------
 1 files changed, 14 insertions(+), 7 deletions(-)

Signed-off-by: Michal Novotny <[email-masked]>
---
 migration.c | 21 ++++++++++++++-------
 1 file changed, 14 insertions(+), 7 deletions(-)

diff --git a/migration.c b/migration.c
index e885bb7..ddbfd45 100644
--- a/migration.c
+++ b/migration.c
@@ -36,7 +36,8 @@
 #endif
 
 enum {
-    MIG_STATE_ERROR,
+    MIG_STATE_ERROR = -1,
+    MIG_STATE_NONE,
     MIG_STATE_SETUP,
     MIG_STATE_CANCELLED,
     MIG_STATE_ACTIVE,
@@ -63,7 +64,7 @@ static NotifierList migration_state_notifiers =
 MigrationState *migrate_get_current(void)
 {
     static MigrationState current_migration = {
-        .state = MIG_STATE_SETUP,
+        .state = MIG_STATE_NONE,
         .bandwidth_limit = MAX_THROTTLE,
         .xbzrle_cache_size = DEFAULT_MIGRATE_CACHE_SIZE,
         .mbps = -1,
@@ -184,9 +185,13 @@ MigrationInfo *qmp_query_migrate(Error **errp)
     MigrationState *s = migrate_get_current();
 
     switch (s->state) {
-    case MIG_STATE_SETUP:
+    case MIG_STATE_NONE:
         /* no migration has happened ever */
         break;
+    case MIG_STATE_SETUP:
+        info->has_status = true;
+        info->status = g_strdup("setup");
+        break;
     case MIG_STATE_ACTIVE:
         info->has_status = true;
         info->status = g_strdup("active");
@@ -258,7 +263,7 @@ void qmp_migrate_set_capabilities(MigrationCapabilityStatusList *params,
     MigrationState *s = migrate_get_current();
     MigrationCapabilityStatusList *cap;
 
-    if (s->state == MIG_STATE_ACTIVE) {
+    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
         error_set(errp, QERR_MIGRATION_ACTIVE);
         return;
     }
@@ -401,7 +406,7 @@ void qmp_migrate(const char *uri, bool has_blk, bool blk,
     }
 #endif
 
-    if (s->state == MIG_STATE_ACTIVE) {
+    if (s->state == MIG_STATE_ACTIVE || s->state == MIG_STATE_SETUP) {
         error_set(errp, QERR_MIGRATION_ACTIVE);
         return;
     }
@@ -551,6 +556,8 @@ static void *migration_thread(void *opaque)
     DPRINTF("beginning savevm\n");
     qemu_savevm_state_begin(s->file, &s->params);
 
+    migrate_set_state(s, MIG_STATE_SETUP, MIG_STATE_ACTIVE);
+
     while (s->state == MIG_STATE_ACTIVE) {
         int64_t current_time;
         uint64_t pending_size;
@@ -641,8 +648,8 @@ static void *migration_thread(void *opaque)
 
 void migrate_fd_connect(MigrationState *s)
 {
-    s->state = MIG_STATE_ACTIVE;
-    trace_migrate_set_state(MIG_STATE_ACTIVE);
+    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;
-- 
1.7.11.7