migration: Make global sem_sync semaphore by channel

This makes easy to debug things because when you want for all threads
to arrive at that semaphore, you know which one your are waiting for.

Signed-off-by: Juan Quintela <quintela@redhat.com>
Message-Id: <20190814020218.1868-3-quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index b542929a7c5cc5a1fe1a9dbd8e7b9e960a56fed7..c7aa3d9a2c61718b77826befe3d026fd5462b922 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -661,6 +661,8 @@ typedef struct {
     uint64_t num_packets;
     /* pages sent through this channel */
     uint64_t num_pages;
+    /* syncs main thread and channels */
+    QemuSemaphore sem_sync;
 }  MultiFDSendParams;
 
 typedef struct {
@@ -896,8 +898,6 @@ struct {
     MultiFDSendParams *params;
     /* array of pages to sent */
     MultiFDPages_t *pages;
-    /* syncs main thread and channels */
-    QemuSemaphore sem_sync;
     /* global number of generated multifd packets */
     uint64_t packet_num;
     /* send channels ready */
@@ -1039,6 +1039,7 @@ void multifd_save_cleanup(void)
         p->c = NULL;
         qemu_mutex_destroy(&p->mutex);
         qemu_sem_destroy(&p->sem);
+        qemu_sem_destroy(&p->sem_sync);
         g_free(p->name);
         p->name = NULL;
         multifd_pages_clear(p->pages);
@@ -1048,7 +1049,6 @@ void multifd_save_cleanup(void)
         p->packet = NULL;
     }
     qemu_sem_destroy(&multifd_send_state->channels_ready);
-    qemu_sem_destroy(&multifd_send_state->sem_sync);
     g_free(multifd_send_state->params);
     multifd_send_state->params = NULL;
     multifd_pages_clear(multifd_send_state->pages);
@@ -1096,7 +1096,7 @@ static void multifd_send_sync_main(RAMState *rs)
         MultiFDSendParams *p = &multifd_send_state->params[i];
 
         trace_multifd_send_sync_main_wait(p->id);
-        qemu_sem_wait(&multifd_send_state->sem_sync);
+        qemu_sem_wait(&p->sem_sync);
     }
     trace_multifd_send_sync_main(multifd_send_state->packet_num);
 }
@@ -1156,7 +1156,7 @@ static void *multifd_send_thread(void *opaque)
             qemu_mutex_unlock(&p->mutex);
 
             if (flags & MULTIFD_FLAG_SYNC) {
-                qemu_sem_post(&multifd_send_state->sem_sync);
+                qemu_sem_post(&p->sem_sync);
             }
             qemu_sem_post(&multifd_send_state->channels_ready);
         } else if (p->quit) {
@@ -1179,7 +1179,7 @@ out:
      */
     if (ret != 0) {
         if (flags & MULTIFD_FLAG_SYNC) {
-            qemu_sem_post(&multifd_send_state->sem_sync);
+            qemu_sem_post(&p->sem_sync);
         }
         qemu_sem_post(&multifd_send_state->channels_ready);
     }
@@ -1225,7 +1225,6 @@ int multifd_save_setup(void)
     multifd_send_state = g_malloc0(sizeof(*multifd_send_state));
     multifd_send_state->params = g_new0(MultiFDSendParams, thread_count);
     multifd_send_state->pages = multifd_pages_init(page_count);
-    qemu_sem_init(&multifd_send_state->sem_sync, 0);
     qemu_sem_init(&multifd_send_state->channels_ready, 0);
 
     for (i = 0; i < thread_count; i++) {
@@ -1233,6 +1232,7 @@ int multifd_save_setup(void)
 
         qemu_mutex_init(&p->mutex);
         qemu_sem_init(&p->sem, 0);
+        qemu_sem_init(&p->sem_sync, 0);
         p->quit = false;
         p->pending_job = 0;
         p->id = i;