On Tue, Aug 27, 2024 at 07:54:29PM +0200, Maciej S. Szmigiero wrote:
> From: "Maciej S. Szmigiero" <maciej.szmigi...@oracle.com>
>
> This is necessary for multifd_send() to be able to be called
> from multiple threads.
>
> Signed-off-by: Maciej S. Szmigiero <maciej.szmigi...@oracle.com>
Would it be much simpler to just use a mutex for enqueue?
Something like:
===8<===
diff --git a/migration/multifd.c b/migration/multifd.c
index 9b200f4ad9..979c9748b5 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -69,6 +69,8 @@ struct {
QemuSemaphore channels_created;
/* send channels ready */
QemuSemaphore channels_ready;
+ /* Mutex to serialize multifd enqueues */
+ QemuMutex multifd_send_mutex;
/*
* Have we already run terminate threads. There is a race when it
* happens that we got one error while we are exiting.
@@ -305,6 +307,8 @@ bool multifd_send(MultiFDSendData **send_data)
MultiFDSendParams *p = NULL; /* make happy gcc */
MultiFDSendData *tmp;
+ QEMU_LOCK_GUARD(&multifd_send_mutex);
+
if (multifd_send_should_exit()) {
return false;
}
@@ -824,6 +828,7 @@ bool multifd_send_setup(void)
multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
qemu_sem_init(&multifd_send_state->channels_created, 0);
qemu_sem_init(&multifd_send_state->channels_ready, 0);
+ qemu_mutex_init(&multifd_send_state->multifd_send_mutex);
qatomic_set(&multifd_send_state->exiting, 0);
multifd_send_state->ops = multifd_ops[migrate_multifd_compression()];
===8<===
Then all the details doesn't need change (meanwhile the perf should be
similar)?
--
Peter Xu
