migration/ram.c: Remove the qemu_mutex_lock in colo_flush_ram_cache.

The code to acquire bitmap_mutex is added in the commit of
"63268c4970a5f126cc9af75f3ccb8057abef5ec0". There is no
need to acquire bitmap_mutex in colo_flush_ram_cache(). This
is because the colo_flush_ram_cache only be called on the COLO
secondary VM, which is the destination side.
On the COLO secondary VM, only the COLO thread will touch
the bitmap of ram cache.

Signed-off-by: Lei Rao <lei.rao@intel.com>
Reviewed-by: Zhang Chen <chen.zhang@intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index 863035d23517c17265593a2d4465f27bcaddab07..2c688f5bbb66101abad50078bdcdb6ea57f24bfe 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -3918,7 +3918,6 @@ void colo_flush_ram_cache(void)
     unsigned long offset = 0;
 
     memory_global_dirty_log_sync();
-    qemu_mutex_lock(&ram_state->bitmap_mutex);
     WITH_RCU_READ_LOCK_GUARD() {
         RAMBLOCK_FOREACH_NOT_IGNORED(block) {
             ramblock_sync_dirty_bitmap(ram_state, block);
@@ -3954,7 +3953,6 @@ void colo_flush_ram_cache(void)
         }
     }
     trace_colo_flush_ram_cache_end();
-    qemu_mutex_unlock(&ram_state->bitmap_mutex);
 }
 
 /**