[PULL 22/30] migration/multifd: clean pages after filling packet

[Juan Quintela]

From: Wei Yang <richardw.y...@linux.intel.com>

This is a preparation for the next patch:

    not use multifd during postcopy.

Without enabling postcopy, everything looks good. While after enabling
postcopy, migration may fail even not use multifd during postcopy. The
reason is the pages is not properly cleared and *old* target page will
continue to be transferred.

After clean pages, migration succeeds.

Signed-off-by: Wei Yang <richardw.y...@linux.intel.com>
Reviewed-by: Juan Quintela <quint...@redhat.com>
Signed-off-by: Juan Quintela <quint...@redhat.com>
---
 migration/ram.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index fd1155f735..561961ef24 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -955,10 +955,10 @@ static int multifd_send_pages(RAMState *rs)
         }
         qemu_mutex_unlock(&p->mutex);
     }
-    p->pages->used = 0;
+    assert(!p->pages->used);
+    assert(!p->pages->block);
 
     p->packet_num = multifd_send_state->packet_num++;
-    p->pages->block = NULL;
     multifd_send_state->pages = p->pages;
     p->pages = pages;
     transferred = ((uint64_t) pages->used) * TARGET_PAGE_SIZE + p->packet_len;
@@ -1154,6 +1154,8 @@ static void *multifd_send_thread(void *opaque)
             p->flags = 0;
             p->num_packets++;
             p->num_pages += used;
+            p->pages->used = 0;
+            p->pages->block = NULL;
             qemu_mutex_unlock(&p->mutex);
 
             trace_multifd_send(p->id, packet_num, used, flags,
-- 
2.24.1