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[PATCH 4/4] migration: Make sure that we don't call write() in case of e
From: |
Juan Quintela |
Subject: |
[PATCH 4/4] migration: Make sure that we don't call write() in case of error |
Date: |
Wed, 18 Dec 2019 06:04:39 +0100 |
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 <address@hidden>
---
migration/ram.c | 19 +++++++++++++++++++
1 file changed, 19 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index 4b44578e57..909ef6d237 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -1601,6 +1601,12 @@ struct {
QemuSemaphore channels_ready;
/* multifd ops */
MultiFDMethods *ops;
+ /*
+ * 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;
/*
@@ -1629,6 +1635,10 @@ 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];
@@ -1710,6 +1720,10 @@ static void multifd_send_terminate_threads(Error *err)
}
}
+ if (atomic_xchg(&multifd_send_state->exiting, 1)) {
+ return;
+ }
+
for (i = 0; i < migrate_multifd_channels(); i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
@@ -1824,6 +1838,10 @@ 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) {
@@ -1938,6 +1956,7 @@ int multifd_save_setup(Error **errp)
multifd_send_state->pages = multifd_pages_init(page_count);
qemu_sem_init(&multifd_send_state->channels_ready, 0);
multifd_send_state->ops = multifd_ops[migrate_multifd_method()];
+ atomic_set(&multifd_send_state->exiting, 0);
for (i = 0; i < thread_count; i++) {
MultiFDSendParams *p = &multifd_send_state->params[i];
--
2.23.0