diff --git a/include/migration/register.h b/include/migration/register.h
index f4f7bdc177..9436a87678 100644
--- a/include/migration/register.h
+++ b/include/migration/register.h
@@ -37,8 +37,21 @@ typedef struct SaveVMHandlers {
     int (*save_setup)(QEMUFile *f, void *opaque);
     void (*save_live_pending)(QEMUFile *f, void *opaque,
                               uint64_t threshold_size,
-                              uint64_t *non_postcopiable_pending,
-                              uint64_t *postcopiable_pending);
+                              uint64_t *res_precopy_only,
+                              uint64_t *res_compatible,
+                              uint64_t *res_postcopy_only);
+    /* Note for save_live_pending:
+     * - res_precopy_only is for data which must be migrated in precopy phase
+     *     or in stopped state, in other words - before target vm start
+     * - res_compatible is for data which may be migrated in any phase
+     * - res_postcopy_only is for data which must be migrated in postcopy phase
+     *     or in stopped state, in other words - after source vm stop
+     *
+     * Sum of res_postcopy_only, res_compatible and res_postcopy_only is the
+     * whole amount of pending data.
+     */
+
+
     LoadStateHandler *load_state;
     int (*load_setup)(QEMUFile *f, void *opaque);
     int (*load_cleanup)(void *opaque);
diff --git a/migration/savevm.h b/migration/savevm.h
index 295c4a1f2c..cf4f0d37ca 100644
--- a/migration/savevm.h
+++ b/migration/savevm.h
@@ -38,8 +38,9 @@ void qemu_savevm_state_complete_postcopy(QEMUFile *f);
 int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only,
                                        bool inactivate_disks);
 void qemu_savevm_state_pending(QEMUFile *f, uint64_t max_size,
-                               uint64_t *res_non_postcopiable,
-                               uint64_t *res_postcopiable);
+                               uint64_t *res_precopy_only,
+                               uint64_t *res_compatible,
+                               uint64_t *res_postcopy_only);
 void qemu_savevm_send_ping(QEMUFile *f, uint32_t value);
 void qemu_savevm_send_open_return_path(QEMUFile *f);
 int qemu_savevm_send_packaged(QEMUFile *f, const uint8_t *buf, size_t len);
diff --git a/hw/s390x/s390-stattrib.c b/hw/s390x/s390-stattrib.c
index 2902f54f11..dd3fbfd1eb 100644
--- a/hw/s390x/s390-stattrib.c
+++ b/hw/s390x/s390-stattrib.c
@@ -183,15 +183,16 @@ static int cmma_save_setup(QEMUFile *f, void *opaque)
 }
 
 static void cmma_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
-                             uint64_t *non_postcopiable_pending,
-                             uint64_t *postcopiable_pending)
+                              uint64_t *res_precopy_only,
+                              uint64_t *res_compatible,
+                              uint64_t *res_postcopy_only)
 {
     S390StAttribState *sas = S390_STATTRIB(opaque);
     S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
     long long res = sac->get_dirtycount(sas);
 
     if (res >= 0) {
-        *non_postcopiable_pending += res;
+        *res_precopy_only += res;
     }
 }
 
diff --git a/migration/block.c b/migration/block.c
index 1f03946797..5652ca3337 100644
--- a/migration/block.c
+++ b/migration/block.c
@@ -866,8 +866,9 @@ static int block_save_complete(QEMUFile *f, void *opaque)
 }
 
 static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
-                               uint64_t *non_postcopiable_pending,
-                               uint64_t *postcopiable_pending)
+                               uint64_t *res_precopy_only,
+                               uint64_t *res_compatible,
+                               uint64_t *res_postcopy_only)
 {
     /* Estimate pending number of bytes to send */
     uint64_t pending;
@@ -888,7 +889,7 @@ static void block_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
 
     DPRINTF("Enter save live pending  %" PRIu64 "\n", pending);
     /* We don't do postcopy */
-    *non_postcopiable_pending += pending;
+    *res_precopy_only += pending;
 }
 
 static int block_load(QEMUFile *f, void *opaque, int version_id)
diff --git a/migration/migration.c b/migration/migration.c
index c99a4e62d7..3beedd676e 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2215,21 +2215,23 @@ typedef enum {
  */
 static MigIterateState migration_iteration_run(MigrationState *s)
 {
-    uint64_t pending_size, pend_post, pend_nonpost;
+    uint64_t pending_size, pend_pre, pend_compat, pend_post;
     bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE;
 
-    qemu_savevm_state_pending(s->to_dst_file, s->threshold_size,
-                              &pend_nonpost, &pend_post);
-    pending_size = pend_nonpost + pend_post;
+    qemu_savevm_state_pending(s->to_dst_file, s->threshold_size, &pend_pre,
+                              &pend_compat, &pend_post);
+    pending_size = pend_pre + pend_compat + pend_post;
 
     trace_migrate_pending(pending_size, s->threshold_size,
-                          pend_post, pend_nonpost);
+                          pend_pre, pend_compat, pend_post);
 
     if (pending_size && pending_size >= s->threshold_size) {
         /* Still a significant amount to transfer */
         if (migrate_postcopy() && !in_postcopy &&
-            pend_nonpost <= s->threshold_size &&
-            atomic_read(&s->start_postcopy)) {
+            pend_pre <= s->threshold_size &&
+            (atomic_read(&s->start_postcopy) ||
+             (pend_pre + pend_compat <= s->threshold_size)))
+        {
             if (postcopy_start(s)) {
                 error_report("%s: postcopy failed to start", __func__);
             }
diff --git a/migration/ram.c b/migration/ram.c
index cb1950f3eb..38b1b2486a 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -2359,8 +2359,9 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
 }
 
 static void ram_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
-                             uint64_t *non_postcopiable_pending,
-                             uint64_t *postcopiable_pending)
+                             uint64_t *res_precopy_only,
+                             uint64_t *res_compatible,
+                             uint64_t *res_postcopy_only)
 {
     RAMState **temp = opaque;
     RAMState *rs = *temp;
@@ -2380,9 +2381,9 @@ static void ram_save_pending(QEMUFile *f, void *opaque, uint64_t max_size,
 
     if (migrate_postcopy_ram()) {
         /* We can do postcopy, and all the data is postcopiable */
-        *postcopiable_pending += remaining_size;
+        *res_compatible += remaining_size;
     } else {
-        *non_postcopiable_pending += remaining_size;
+        *res_precopy_only += remaining_size;
     }
 }
 
diff --git a/migration/savevm.c b/migration/savevm.c
index b7908f62be..c3c60a15e3 100644
--- a/migration/savevm.c
+++ b/migration/savevm.c
@@ -1218,13 +1218,15 @@ int qemu_savevm_state_complete_precopy(QEMUFile *f, bool iterable_only,
  * for units that can't do postcopy.
  */
 void qemu_savevm_state_pending(QEMUFile *f, uint64_t threshold_size,
-                               uint64_t *res_non_postcopiable,
-                               uint64_t *res_postcopiable)
+                               uint64_t *res_precopy_only,
+                               uint64_t *res_compatible,
+                               uint64_t *res_postcopy_only)
 {
     SaveStateEntry *se;
 
-    *res_non_postcopiable = 0;
-    *res_postcopiable = 0;
+    *res_precopy_only = 0;
+    *res_compatible = 0;
+    *res_postcopy_only = 0;
 
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
@@ -1237,7 +1239,8 @@ void qemu_savevm_state_pending(QEMUFile *f, uint64_t threshold_size,
             }
         }
         se->ops->save_live_pending(f, se->opaque, threshold_size,
-                                   res_non_postcopiable, res_postcopiable);
+                                   res_precopy_only, res_compatible,
+                                   res_postcopy_only);
     }
 }
 
diff --git a/migration/trace-events b/migration/trace-events
index 6f29fcc686..a04fffb877 100644
--- a/migration/trace-events
+++ b/migration/trace-events
@@ -86,7 +86,7 @@ migrate_fd_cleanup(void) ""
 migrate_fd_error(const char *error_desc) "error=%s"
 migrate_fd_cancel(void) ""
 migrate_handle_rp_req_pages(const char *rbname, size_t start, size_t len) "in %s at 0x%zx len 0x%zx"
-migrate_pending(uint64_t size, uint64_t max, uint64_t post, uint64_t nonpost) "pending size %" PRIu64 " max %" PRIu64 " (post=%" PRIu64 " nonpost=%" PRIu64 ")"
+migrate_pending(uint64_t size, uint64_t max, uint64_t pre, uint64_t compat, uint64_t post) "pending size %" PRIu64 " max %" PRIu64 " (pre = %" PRIu64 " compat=%" PRIu64 " post=%" PRIu64 ")"
 migrate_send_rp_message(int msg_type, uint16_t len) "%d: len %d"
 migration_completion_file_err(void) ""
 migration_completion_postcopy_end(void) ""
