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migration: Make sure that we don't call write() in case of error 

If we are exiting due to an error/finish/.... Just don't try to even
touch the channel with one IO operation.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
This commit is contained in:
Juan Quintela 2019-12-18 05:36:22 +01:00
parent b99784ef6c
commit 4d65a6216b
1 changed files with 25 additions and 0 deletions
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25
migration/ram.c
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@ -900,6 +900,12 @@ struct {
uint64_t packet_num;
/* send channels ready */
QemuSemaphore channels_ready;
/*
* Have we already run terminate threads. There is a race when it
* happens that we got one error while we are exiting.
* We will use atomic operations. Only valid values are 0 and 1.
*/
int exiting;
} *multifd_send_state;
/*
@ -928,6 +934,10 @@ static int multifd_send_pages(RAMState *rs)
MultiFDPages_t *pages = multifd_send_state->pages;
uint64_t transferred;
if (atomic_read(&multifd_send_state->exiting)) {
return -1;
}
qemu_sem_wait(&multifd_send_state->channels_ready);
for (i = next_channel;; i = (i + 1) % migrate_multifd_channels()) {
p = &multifd_send_state->params[i];
@ -1009,6 +1019,16 @@ 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 (atomic_xchg(&multifd_send_state->exiting, 1)) {
return;
}
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
@ -1118,6 +1138,10 @@ static void *multifd_send_thread(void *opaque)
while (true) {
qemu_sem_wait(&p->sem);
if (atomic_read(&multifd_send_state->exiting)) {
break;
}
qemu_mutex_lock(&p->mutex);
if (p->pending_job) {
@ -1224,6 +1248,7 @@ int multifd_save_setup(void)
multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
multifd_send_state->pages = multifd_pages_init(page_count);
qemu_sem_init(&multifd_send_state->channels_ready, 0);
atomic_set(&multifd_send_state->exiting, 0);
for (i = 0; i < thread_count; i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];