[Qemu-devel] [PULL 32/33] migration: Make global sem_sync semaphore by channel

["Dr. David Alan Gilbert (git)" <dgilbert@redhat.com>]

From: Juan Quintela <quintela@redhat.com>

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>
---
 migration/ram.c | 14 +++++++-------
 1 file changed, 7 insertions(+), 7 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index b542929a7c..c7aa3d9a2c 100644
--- 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;
-- 
2.21.0