Il 18/10/2012 10:39, Paolo Bonzini ha scritto:
> in this function. Perhaps it is better if you make an invariant that
> the loop is entered and exited with the BQL taken, and it is only
> unlocked in the middle. It makes sense once you fold everything in
> migration.c.
i.e. this:
diff --git a/migration.c b/migration.c
index 554d79a..bd9fe2d 100644
--- a/migration.c
+++ b/migration.c
@@ -661,23 +661,18 @@ static void *buffered_file_thread(void *opaque)
ret = qemu_savevm_state_begin(m->file, &m->params);
if (ret < 0) {
DPRINTF("failed, %d\n", ret);
- qemu_mutex_unlock_iothread();
goto out;
}
- qemu_mutex_unlock_iothread();
while (true) {
int64_t current_time = qemu_get_clock_ms(rt_clock);
uint64_t pending_size;
- qemu_mutex_lock_iothread();
if (m->state != MIG_STATE_ACTIVE) {
DPRINTF("put_ready returning because of non-active state\n");
- qemu_mutex_unlock_iothread();
break;
}
if (m->complete) {
- qemu_mutex_unlock_iothread();
break;
}
if (s->bytes_xfer < s->xfer_limit) {
@@ -687,7 +682,6 @@ static void *buffered_file_thread(void *opaque)
if (pending_size && pending_size >= max_size) {
ret = qemu_savevm_state_iterate(m->file);
if (ret < 0) {
- qemu_mutex_unlock_iothread();
break;
}
} else {
@@ -708,7 +702,6 @@ static void *buffered_file_thread(void *opaque)
printf("vm_stop 2 %ld\n", end_time - start_time);
ret = qemu_savevm_state_complete(m->file);
if (ret < 0) {
- qemu_mutex_unlock_iothread();
break;
} else {
end_time = qemu_get_clock_ms(rt_clock);
@@ -729,8 +722,8 @@ static void *buffered_file_thread(void *opaque)
last_round = true;
}
}
- qemu_mutex_unlock_iothread();
+ qemu_mutex_unlock_iothread();
if (current_time >= initial_time + BUFFER_DELAY) {
uint64_t transferred_bytes = s->bytes_xfer;
uint64_t time_spent = current_time - initial_time;
@@ -749,9 +742,11 @@ static void *buffered_file_thread(void *opaque)
usleep((initial_time + BUFFER_DELAY - current_time)*1000);
}
buffered_flush(s);
+ qemu_mutex_lock_iothread();
}
out:
+ qemu_mutex_unlock_iothread();
if (ret < 0) {
migrate_fd_error(m);
}
BTW the completion (basically the "else" starting at "int old_vm_running =
runstate_is_running()" looks much nicer in a separate function, like:
if (pending_size && pending_size >= max_size) {
ret = qemu_savevm_state_iterate(m->file);
} else {
ret = migration_complete(m);
last_round = true;
}
if (ret < 0) {
break;
}
Paolo
