From: Peter Xu <peterx@redhat.com>
Multifd send side has two fields to indicate error quits:
- MultiFDSendParams.quit
- &multifd_send_state->exiting
Merge them into the global one. The replacement is done by changing all
p->quit checks into the global var check. The global check doesn't need
any lock.
A few more things done on top of this altogether:
- multifd_send_terminate_threads()
Moving the xchg() of &multifd_send_state->exiting upper, so as to cover
the tracepoint, migrate_set_error() and migrate_set_state().
- multifd_send_sync_main()
In the 2nd loop, add one more check over the global var to make sure we
don't keep the looping if QEMU already decided to quit.
- multifd_tls_outgoing_handshake()
Use multifd_send_terminate_threads() to set the error state. That has
a benefit of updating MigrationState.error to that error too, so we can
persist that 1st error we hit in that specific channel.
- multifd_new_send_channel_async()
Take similar approach like above, drop the migrate_set_error() because
multifd_send_terminate_threads() already covers that. Unwrap the helper
multifd_new_send_channel_cleanup() along the way; not really needed.
Reviewed-by: Fabiano Rosas <farosas@suse.de>
Link: https://lore.kernel.org/r/20240202102857.110210-4-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
---
migration/multifd.h | 2 --
migration/multifd.c | 85 ++++++++++++++++++---------------------------
2 files changed, 33 insertions(+), 54 deletions(-)
diff --git a/migration/multifd.h b/migration/multifd.h
index 35d11f103c..7c040cb85a 100644
--- a/migration/multifd.h
+++ b/migration/multifd.h
@@ -95,8 +95,6 @@ typedef struct {
QemuMutex mutex;
/* is this channel thread running */
bool running;
- /* should this thread finish */
- bool quit;
/* multifd flags for each packet */
uint32_t flags;
/* global number of generated multifd packets */
diff --git a/migration/multifd.c b/migration/multifd.c
index b8d2c96533..2c98023d67 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -372,6 +372,11 @@ struct {
MultiFDMethods *ops;
} *multifd_send_state;
+static bool multifd_send_should_exit(void)
+{
+ return qatomic_read(&multifd_send_state->exiting);
+}
+
/*
* The migration thread can wait on either of the two semaphores. This
* function can be used to kick the main thread out of waiting on either of
@@ -409,7 +414,7 @@ static int multifd_send_pages(void)
MultiFDSendParams *p = NULL; /* make happy gcc */
MultiFDPages_t *pages = multifd_send_state->pages;
- if (qatomic_read(&multifd_send_state->exiting)) {
+ if (multifd_send_should_exit()) {
return -1;
}
@@ -421,14 +426,11 @@ static int multifd_send_pages(void)
*/
next_channel %= migrate_multifd_channels();
for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) {
- p = &multifd_send_state->params[i];
-
- qemu_mutex_lock(&p->mutex);
- if (p->quit) {
- error_report("%s: channel %d has already quit!", __func__, i);
- qemu_mutex_unlock(&p->mutex);
+ if (multifd_send_should_exit()) {
return -1;
}
+ p = &multifd_send_state->params[i];
+ qemu_mutex_lock(&p->mutex);
if (!p->pending_job) {
p->pending_job++;
next_channel = (i + 1) % migrate_multifd_channels();
@@ -483,6 +485,16 @@ static void multifd_send_terminate_threads(Error *err)
{
int i;
+ /*
+ * We don't want to exit each threads twice. Depending on where
+ * we get the error, or if there are two independent errors in two
+ * threads at the same time, we can end calling this function
+ * twice.
+ */
+ if (qatomic_xchg(&multifd_send_state->exiting, 1)) {
+ return;
+ }
+
trace_multifd_send_terminate_threads(err != NULL);
if (err) {
@@ -497,26 +509,13 @@ static void multifd_send_terminate_threads(Error *err)
}
}
- /*
- * We don't want to exit each threads twice. Depending on where
- * we get the error, or if there are two independent errors in two
- * threads at the same time, we can end calling this function
- * twice.
- */
- if (qatomic_xchg(&multifd_send_state->exiting, 1)) {
- return;
- }
-
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
- qemu_mutex_lock(&p->mutex);
- p->quit = true;
qemu_sem_post(&p->sem);
if (p->c) {
qio_channel_shutdown(p->c, QIO_CHANNEL_SHUTDOWN_BOTH, NULL);
}
- qemu_mutex_unlock(&p->mutex);
}
}
@@ -615,16 +614,13 @@ int multifd_send_sync_main(void)
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
- trace_multifd_send_sync_main_signal(p->id);
-
- qemu_mutex_lock(&p->mutex);
-
- if (p->quit) {
- error_report("%s: channel %d has already quit", __func__, i);
- qemu_mutex_unlock(&p->mutex);
+ if (multifd_send_should_exit()) {
return -1;
}
+ trace_multifd_send_sync_main_signal(p->id);
+
+ qemu_mutex_lock(&p->mutex);
p->packet_num = multifd_send_state->packet_num++;
p->flags |= MULTIFD_FLAG_SYNC;
p->pending_job++;
@@ -634,6 +630,10 @@ int multifd_send_sync_main(void)
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
+ if (multifd_send_should_exit()) {
+ return -1;
+ }
+
qemu_sem_wait(&multifd_send_state->channels_ready);
trace_multifd_send_sync_main_wait(p->id);
qemu_sem_wait(&p->sem_sync);
@@ -671,7 +671,7 @@ static void *multifd_send_thread(void *opaque)
qemu_sem_post(&multifd_send_state->channels_ready);
qemu_sem_wait(&p->sem);
- if (qatomic_read(&multifd_send_state->exiting)) {
+ if (multifd_send_should_exit()) {
break;
}
qemu_mutex_lock(&p->mutex);
@@ -786,12 +786,7 @@ static void multifd_tls_outgoing_handshake(QIOTask *task,
trace_multifd_tls_outgoing_handshake_error(ioc, error_get_pretty(err));
- migrate_set_error(migrate_get_current(), err);
- /*
- * Error happen, mark multifd_send_thread status as 'quit' although it
- * is not created, and then tell who pay attention to me.
- */
- p->quit = true;
+ multifd_send_terminate_threads(err);
multifd_send_kick_main(p);
error_free(err);
}
@@ -857,22 +852,6 @@ static bool multifd_channel_connect(MultiFDSendParams *p,
return true;
}
-static void multifd_new_send_channel_cleanup(MultiFDSendParams *p,
- QIOChannel *ioc, Error *err)
-{
- migrate_set_error(migrate_get_current(), err);
- /* Error happen, we need to tell who pay attention to me */
- multifd_send_kick_main(p);
- /*
- * Although multifd_send_thread is not created, but main migration
- * thread need to judge whether it is running, so we need to mark
- * its status.
- */
- p->quit = true;
- object_unref(OBJECT(ioc));
- error_free(err);
-}
-
static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
{
MultiFDSendParams *p = opaque;
@@ -889,7 +868,10 @@ static void multifd_new_send_channel_async(QIOTask *task, gpointer opaque)
}
trace_multifd_new_send_channel_async_error(p->id, local_err);
- multifd_new_send_channel_cleanup(p, ioc, local_err);
+ multifd_send_terminate_threads(local_err);
+ multifd_send_kick_main(p);
+ object_unref(OBJECT(ioc));
+ error_free(local_err);
}
static void multifd_new_send_channel_create(gpointer opaque)
@@ -921,7 +903,6 @@ int multifd_save_setup(Error **errp)
qemu_mutex_init(&p->mutex);
qemu_sem_init(&p->sem, 0);
qemu_sem_init(&p->sem_sync, 0);
- p->quit = false;
p->pending_job = 0;
p->id = i;
p->pages = multifd_pages_init(page_count);
--
2.43.0