[PATCH 1/4] multifd: wait for channels_ready before sending sync

[Elena Ufimtseva]

In multifd_send_sync_main we need to wait for channels_ready
before submitting sync packet as the threads may still be sending
their previous pages.
There is also no need to check for channels_ready in the loop
before the wait for sem_sync, next iteration of sending pages
or another sync will start with waiting for channels_ready
semaphore.
Changes to commit 90b3cec351996dd8ef4eb847ad38607812c5e7f5
("multifd: Fix the number of channels ready")

Signed-off-by: Elena Ufimtseva <elena.ufimtseva@oracle.com>
---
 migration/multifd.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/migration/multifd.c b/migration/multifd.c
index 0f6b203877..e61e458151 100644
--- a/migration/multifd.c
+++ b/migration/multifd.c
@@ -595,6 +595,7 @@ int multifd_send_sync_main(QEMUFile *f)
         }
     }
 
+    qemu_sem_wait(&multifd_send_state->channels_ready);
     /*
      * When using zero-copy, it's necessary to flush the pages before any of
      * the pages can be sent again, so we'll make sure the new version of the
@@ -630,7 +631,6 @@ int multifd_send_sync_main(QEMUFile *f)
     for (i = 0; i < migrate_multifd_channels(); i++) {
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
-        qemu_sem_wait(&multifd_send_state->channels_ready);
         trace_multifd_send_sync_main_wait(p->id);
         qemu_sem_wait(&p->sem_sync);
 
-- 
2.34.1