rp_pong_acks tells if it has ever received one pong. QemuEvent is
better suited for this usage because it represents a boolean rather
than integer and will not decrement with the wait operation.
pause_event can utilize qemu_event_reset() to discard events.
Signed-off-by: Akihiko Odaki <akihiko.od...@daynix.com>
---
migration/migration.h | 6 +++---
migration/migration.c | 29 +++++++++++++----------------
2 files changed, 16 insertions(+), 19 deletions(-)
diff --git a/migration/migration.h b/migration/migration.h
index d53f7cad84d8..11dba5f4da77 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -342,11 +342,11 @@ struct MigrationState {
*/
QemuSemaphore rp_sem;
/*
- * We post to this when we got one PONG from dest. So far it's an
+ * We set this when we got one PONG from dest. So far it's an
* easy way to know the main channel has successfully established
* on dest QEMU.
*/
- QemuSemaphore rp_pong_acks;
+ QemuEvent rp_pong_acks;
} rp_state;
double mbps;
@@ -379,7 +379,7 @@ struct MigrationState {
QemuSemaphore wait_unplug_sem;
/* Migration is paused due to pause-before-switchover */
- QemuSemaphore pause_sem;
+ QemuEvent pause_event;
/* The semaphore is used to notify COLO thread that failover is finished */
QemuSemaphore colo_exit_sem;
diff --git a/migration/migration.c b/migration/migration.c
index 4697732bef91..053c23c58d82 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -1630,7 +1630,7 @@ void migration_cancel(void)
}
/* If the migration is paused, kick it out of the pause */
if (old_state == MIGRATION_STATUS_PRE_SWITCHOVER) {
- qemu_sem_post(&s->pause_sem);
+ qemu_event_set(&s->pause_event);
}
migrate_set_state(&s->state, old_state, MIGRATION_STATUS_CANCELLING);
} while (s->state != MIGRATION_STATUS_CANCELLING);
@@ -2342,7 +2342,7 @@ void qmp_migrate_continue(MigrationStatus state, Error
**errp)
MigrationStatus_str(s->state));
return;
}
- qemu_sem_post(&s->pause_sem);
+ qemu_event_set(&s->pause_event);
}
int migration_rp_wait(MigrationState *s)
@@ -2550,7 +2550,7 @@ static void *source_return_path_thread(void *opaque)
case MIG_RP_MSG_PONG:
tmp32 = ldl_be_p(buf);
trace_source_return_path_thread_pong(tmp32);
- qemu_sem_post(&ms->rp_state.rp_pong_acks);
+ qemu_event_set(&ms->rp_state.rp_pong_acks);
break;
case MIG_RP_MSG_REQ_PAGES:
@@ -2693,7 +2693,7 @@ static inline void
migration_wait_main_channel(MigrationState *ms)
{
/* Wait until one PONG message received */
- qemu_sem_wait(&ms->rp_state.rp_pong_acks);
+ qemu_event_wait(&ms->rp_state.rp_pong_acks);
}
/*
@@ -2911,21 +2911,18 @@ static bool migration_switchover_prepare(MigrationState
*s)
return true;
}
- /* Since leaving this state is not atomic with posting the semaphore
+ /*
+ * Since leaving this state is not atomic with setting the event
* it's possible that someone could have issued multiple migrate_continue
- * and the semaphore is incorrectly positive at this point;
- * the docs say it's undefined to reinit a semaphore that's already
- * init'd, so use timedwait to eat up any existing posts.
+ * and the event is incorrectly set at this point so reset it.
*/
- while (qemu_sem_timedwait(&s->pause_sem, 1) == 0) {
- /* This block intentionally left blank */
- }
+ qemu_event_reset(&s->pause_event);
/* Update [POSTCOPY_]ACTIVE to PRE_SWITCHOVER */
migrate_set_state(&s->state, s->state, MIGRATION_STATUS_PRE_SWITCHOVER);
bql_unlock();
- qemu_sem_wait(&s->pause_sem);
+ qemu_event_wait(&s->pause_event);
bql_lock();
/*
@@ -4057,10 +4054,10 @@ static void migration_instance_finalize(Object *obj)
qemu_mutex_destroy(&ms->qemu_file_lock);
qemu_sem_destroy(&ms->wait_unplug_sem);
qemu_sem_destroy(&ms->rate_limit_sem);
- qemu_sem_destroy(&ms->pause_sem);
+ qemu_event_destroy(&ms->pause_event);
qemu_sem_destroy(&ms->postcopy_pause_sem);
qemu_sem_destroy(&ms->rp_state.rp_sem);
- qemu_sem_destroy(&ms->rp_state.rp_pong_acks);
+ qemu_event_destroy(&ms->rp_state.rp_pong_acks);
qemu_sem_destroy(&ms->postcopy_qemufile_src_sem);
error_free(ms->error);
}
@@ -4072,14 +4069,14 @@ static void migration_instance_init(Object *obj)
ms->state = MIGRATION_STATUS_NONE;
ms->mbps = -1;
ms->pages_per_second = -1;
- qemu_sem_init(&ms->pause_sem, 0);
+ qemu_event_init(&ms->pause_event, false);
qemu_mutex_init(&ms->error_mutex);
migrate_params_init(&ms->parameters);
qemu_sem_init(&ms->postcopy_pause_sem, 0);
qemu_sem_init(&ms->rp_state.rp_sem, 0);
- qemu_sem_init(&ms->rp_state.rp_pong_acks, 0);
+ qemu_event_init(&ms->rp_state.rp_pong_acks, false);
qemu_sem_init(&ms->rate_limit_sem, 0);
qemu_sem_init(&ms->wait_unplug_sem, 0);
qemu_sem_init(&ms->postcopy_qemufile_src_sem, 0);
--
2.49.0
