qemu-kvm/SOURCES/kvm-migration-Make-sure-that-we-don-t-call-write-in-case.patch

95 lines
3.2 KiB
Diff

From 71b05ab5782aa1e38c016be6264a14f5650d2a87 Mon Sep 17 00:00:00 2001
From: Juan Quintela <quintela@redhat.com>
Date: Tue, 3 Mar 2020 14:51:35 +0000
Subject: [PATCH 03/18] migration: Make sure that we don't call write() in case
of error
RH-Author: Juan Quintela <quintela@redhat.com>
Message-id: <20200303145143.149290-3-quintela@redhat.com>
Patchwork-id: 94113
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH v2 02/10] migration: Make sure that we don't call write() in case of error
Bugzilla: 1738451
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
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>
(cherry picked from commit 4d65a6216bfc44891ac298b74a6921d479805131)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
migration/ram.c | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)
diff --git a/migration/ram.c b/migration/ram.c
index 65580e3..8c783b3 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -899,6 +899,12 @@ 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;
/*
@@ -927,6 +933,10 @@ 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];
@@ -1008,6 +1018,16 @@ 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];
@@ -1117,6 +1137,10 @@ 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) {
@@ -1225,6 +1249,7 @@ 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];
--
1.8.3.1