[Qemu-devel] [RFC PATCH v4 12/28] arch_init: Start to trace dirty pages of SVM

[zhanghailiang]

we will use this dirty bitmap together with VM's cache RAM dirty bitmap
to decide which page in cache should be flushed into VM's RAM.

Signed-off-by: zhanghailiang <zhang.zhanghaili...@huawei.com>
---
 arch_init.c | 15 +++++++++++++++
 1 file changed, 15 insertions(+)

diff --git a/arch_init.c b/arch_init.c
index e32d258..f3f2460 100644
--- a/arch_init.c
+++ b/arch_init.c
@@ -1277,6 +1277,7 @@ static int ram_load(QEMUFile *f, void *opaque, int 
version_id)
 void create_and_init_ram_cache(void)
 {
     RAMBlock *block;
+    int64_t ram_cache_pages = last_ram_offset() >> TARGET_PAGE_BITS;
 
     rcu_read_lock();
     QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
@@ -1286,6 +1287,14 @@ void create_and_init_ram_cache(void)
     rcu_read_unlock();
 
     ram_cache_enable = true;
+    /*
+    * Start dirty log for slave VM, we will use this dirty bitmap together with
+    * VM's cache RAM dirty bitmap to decide which page in cache should be
+    * flushed into VM's RAM.
+    */
+    migration_bitmap = bitmap_new(ram_cache_pages);
+    migration_dirty_pages = 0;
+    memory_global_dirty_log_start();
 }
 
 void release_ram_cache(void)
@@ -1294,6 +1303,12 @@ void release_ram_cache(void)
 
     ram_cache_enable = false;
 
+    if (migration_bitmap) {
+        memory_global_dirty_log_stop();
+        g_free(migration_bitmap);
+        migration_bitmap = NULL;
+    }
+
     rcu_read_lock();
     QLIST_FOREACH_RCU(block, &ram_list.blocks, next) {
         g_free(block->host_cache);
-- 
1.7.12.4