[PATCH v3 6/7] memory: make global_dirty_log a bitmask

[huangy81@chinatelecom.cn]

From: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>

dirty rate measurement may start or stop dirty logging during
calculation. this conflict with migration because stop dirty
log make migration leave dirty pages out then that'll be a problem.

make global_dirty_log a bitmask can let both migration and dirty
rate measurement work fine. introduce GLOBAL_DIRTY_MIGRATION and
GLOBAL_DIRTY_DIRTY_RATE to distinguish what current dirty log aims
for, migration or dirty rate.

all references to global_dirty_log should be untouched because any bit
set there should justify that global dirty logging is enabled.

Signed-off-by: Hyman Huang(黄勇) <huangy81@chinatelecom.cn>
---
 include/exec/memory.h | 13 ++++++++++---
 migration/ram.c       |  8 ++++----
 softmmu/memory.c      | 36 +++++++++++++++++++++++++++---------
 3 files changed, 41 insertions(+), 16 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index c158fd7084..94c7088299 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -55,7 +55,10 @@ static inline void fuzz_dma_read_cb(size_t addr,
 }
 #endif
 
-extern bool global_dirty_log;
+#define GLOBAL_DIRTY_MIGRATION  (1U<<0)
+#define GLOBAL_DIRTY_DIRTY_RATE (1U<<1)
+
+extern int global_dirty_log;
 
 typedef struct MemoryRegionOps MemoryRegionOps;
 
@@ -2099,13 +2102,17 @@ void memory_listener_unregister(MemoryListener *listener);
 
 /**
  * memory_global_dirty_log_start: begin dirty logging for all regions
+ *
+ * @flags: purpose of start dirty log, migration or dirty rate
  */
-void memory_global_dirty_log_start(void);
+void memory_global_dirty_log_start(int flags);
 
 /**
  * memory_global_dirty_log_stop: end dirty logging for all regions
+ *
+ * @flags: purpose of stop dirty log, migration or dirty rate
  */
-void memory_global_dirty_log_stop(void);
+void memory_global_dirty_log_stop(int flags);
 
 void mtree_info(bool flatview, bool dispatch_tree, bool owner, bool disabled);
 
diff --git a/migration/ram.c b/migration/ram.c
index 60ea913c54..9ce31af9d1 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2190,7 +2190,7 @@ static void ram_save_cleanup(void *opaque)
         /* caller have hold iothread lock or is in a bh, so there is
          * no writing race against the migration bitmap
          */
-        memory_global_dirty_log_stop();
+        memory_global_dirty_log_stop(GLOBAL_DIRTY_MIGRATION);
     }
 
     RAMBLOCK_FOREACH_NOT_IGNORED(block) {
@@ -2652,7 +2652,7 @@ static void ram_init_bitmaps(RAMState *rs)
         ram_list_init_bitmaps();
         /* We don't use dirty log with background snapshots */
         if (!migrate_background_snapshot()) {
-            memory_global_dirty_log_start();
+            memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
             migration_bitmap_sync_precopy(rs);
         }
     }
@@ -3393,7 +3393,7 @@ void colo_incoming_start_dirty_log(void)
             /* Discard this dirty bitmap record */
             bitmap_zero(block->bmap, block->max_length >> TARGET_PAGE_BITS);
         }
-        memory_global_dirty_log_start();
+        memory_global_dirty_log_start(GLOBAL_DIRTY_MIGRATION);
     }
     ram_state->migration_dirty_pages = 0;
     qemu_mutex_unlock_ramlist();
@@ -3405,7 +3405,7 @@ void colo_release_ram_cache(void)
 {
     RAMBlock *block;
 
-    memory_global_dirty_log_stop();
+    memory_global_dirty_log_stop(GLOBAL_DIRTY_MIGRATION);
     RAMBLOCK_FOREACH_NOT_IGNORED(block) {
         g_free(block->bmap);
         block->bmap = NULL;
diff --git a/softmmu/memory.c b/softmmu/memory.c
index c19b0be6b1..b93baba82d 100644
--- a/softmmu/memory.c
+++ b/softmmu/memory.c
@@ -39,7 +39,7 @@
 static unsigned memory_region_transaction_depth;
 static bool memory_region_update_pending;
 static bool ioeventfd_update_pending;
-bool global_dirty_log;
+int global_dirty_log;
 
 static QTAILQ_HEAD(, MemoryListener) memory_listeners
     = QTAILQ_HEAD_INITIALIZER(memory_listeners);
@@ -2659,14 +2659,20 @@ void memory_global_after_dirty_log_sync(void)
 
 static VMChangeStateEntry *vmstate_change;
 
-void memory_global_dirty_log_start(void)
+void memory_global_dirty_log_start(int flags)
 {
     if (vmstate_change) {
         qemu_del_vm_change_state_handler(vmstate_change);
         vmstate_change = NULL;
     }
 
-    global_dirty_log = true;
+    if (flags & GLOBAL_DIRTY_MIGRATION) {
+        global_dirty_log |= GLOBAL_DIRTY_MIGRATION;
+    }
+
+    if (flags & GLOBAL_DIRTY_DIRTY_RATE) {
+        global_dirty_log |= GLOBAL_DIRTY_DIRTY_RATE;
+    }
 
     MEMORY_LISTENER_CALL_GLOBAL(log_global_start, Forward);
 
@@ -2676,9 +2682,15 @@ void memory_global_dirty_log_start(void)
     memory_region_transaction_commit();
 }
 
-static void memory_global_dirty_log_do_stop(void)
+static void memory_global_dirty_log_do_stop(int flags)
 {
-    global_dirty_log = false;
+    if (flags & GLOBAL_DIRTY_MIGRATION) {
+        global_dirty_log &= ~GLOBAL_DIRTY_MIGRATION;
+    }
+
+    if (flags & GLOBAL_DIRTY_DIRTY_RATE) {
+        global_dirty_log &= ~GLOBAL_DIRTY_DIRTY_RATE;
+    }
 
     /* Refresh DIRTY_MEMORY_MIGRATION bit.  */
     memory_region_transaction_begin();
@@ -2691,8 +2703,10 @@ static void memory_global_dirty_log_do_stop(void)
 static void memory_vm_change_state_handler(void *opaque, bool running,
                                            RunState state)
 {
+    int *flags = opaque;
     if (running) {
-        memory_global_dirty_log_do_stop();
+        memory_global_dirty_log_do_stop(*flags);
+        g_free(opaque);
 
         if (vmstate_change) {
             qemu_del_vm_change_state_handler(vmstate_change);
@@ -2701,18 +2715,22 @@ static void memory_vm_change_state_handler(void *opaque, bool running,
     }
 }
 
-void memory_global_dirty_log_stop(void)
+void memory_global_dirty_log_stop(int flags)
 {
+    int *opaque = NULL;
     if (!runstate_is_running()) {
         if (vmstate_change) {
             return;
         }
+
+        opaque = g_malloc0(sizeof(opaque));
+        *opaque = flags;
         vmstate_change = qemu_add_vm_change_state_handler(
-                                memory_vm_change_state_handler, NULL);
+                                memory_vm_change_state_handler, opaque);
         return;
     }
 
-    memory_global_dirty_log_do_stop();
+    memory_global_dirty_log_do_stop(flags);
 }
 
 static void listener_add_address_space(MemoryListener *listener,
-- 
2.18.2