migration: Rename res_{postcopy,precopy}_only

Once that res_compatible is removed, they don't make sense anymore.
We remove the _only preffix.  And to make things clearer we rename
them to must_precopy and can_postcopy.

Reviewed-by: Vladimir Sementsov-Ogievskiy <vsementsov@yandex-team.ru>
Signed-off-by: Juan Quintela <quintela@redhat.com>

hw/s390x/s390-stattrib.c

@@ -182,16 +182,15 @@ static int cmma_save_setup(QEMUFile *f, void *opaque)
     return 0;
 }
 
-static void cmma_state_pending(void *opaque,
-                               uint64_t *res_precopy_only,
-                               uint64_t *res_postcopy_only)
+static void cmma_state_pending(void *opaque, uint64_t *must_precopy,
+                               uint64_t *can_postcopy)
 {
     S390StAttribState *sas = S390_STATTRIB(opaque);
     S390StAttribClass *sac = S390_STATTRIB_GET_CLASS(sas);
     long long res = sac->get_dirtycount(sas);
 
     if (res >= 0) {
-        *res_precopy_only += res;
+        *must_precopy += res;
     }
 }
 

hw/vfio/migration.c

@@ -456,9 +456,8 @@ static void vfio_save_cleanup(void *opaque)
     trace_vfio_save_cleanup(vbasedev->name);
 }
 
-static void vfio_state_pending(void *opaque,
-                               uint64_t *res_precopy_only,
-                               uint64_t *res_postcopy_only)
+static void vfio_state_pending(void *opaque, uint64_t *must_precopy,
+                               uint64_t *can_postcopy)
 {
     VFIODevice *vbasedev = opaque;
     VFIOMigration *migration = vbasedev->migration;
@@ -469,10 +468,9 @@ static void vfio_state_pending(void *opaque,
         return;
     }
 
-    *res_precopy_only += migration->pending_bytes;
+    *must_precopy += migration->pending_bytes;
 
-    trace_vfio_state_pending(vbasedev->name, *res_precopy_only,
-                            *res_postcopy_only);
+    trace_vfio_state_pending(vbasedev->name, *must_precopy, *can_postcopy);
 }
 
 static int vfio_save_iterate(QEMUFile *f, void *opaque)

include/migration/register.h

@@ -47,22 +47,25 @@ typedef struct SaveVMHandlers {
     /* This runs outside the iothread lock!  */
     int (*save_setup)(QEMUFile *f, void *opaque);
     /* 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_postcopy_only is for data which must be migrated in postcopy phase
-     *     or in stopped state, in other words - after source vm stop
+     * must_precopy:
+     * - must be migrated in precopy or in stopped state
+     * - i.e. must be migrated before target start
      *
-     * Sum of res_postcopy_only and res_postcopy_only is the whole
-     * amount of pending data.
+     * can_postcopy:
+     * - can migrate in postcopy or in stopped state
+     * - i.e. can migrate after target start
+     * - some can also be migrated during precopy (RAM)
+     * - some must be migrated after source stops (block-dirty-bitmap)
+     *
+     * Sum of can_postcopy and must_postcopy is the whole amount of
+     * pending data.
      */
     /* This estimates the remaining data to transfer */
-    void (*state_pending_estimate)(void *opaque,
-                                   uint64_t *res_precopy_only,
-                                   uint64_t *res_postcopy_only);
+    void (*state_pending_estimate)(void *opaque, uint64_t *must_precopy,
+                                   uint64_t *can_postcopy);
     /* This calculate the exact remaining data to transfer */
-    void (*state_pending_exact)(void *opaque,
-                                uint64_t *res_precopy_only,
-                                uint64_t *res_postcopy_only);
+    void (*state_pending_exact)(void *opaque, uint64_t *must_precopy,
+                                uint64_t *can_postcopy);
     LoadStateHandler *load_state;
     int (*load_setup)(QEMUFile *f, void *opaque);
     int (*load_cleanup)(void *opaque);

migration/block-dirty-bitmap.c

@@ -763,8 +763,8 @@ static int dirty_bitmap_save_complete(QEMUFile *f, void *opaque)
 }
 
 static void dirty_bitmap_state_pending(void *opaque,
-                                       uint64_t *res_precopy_only,
-                                       uint64_t *res_postcopy_only)
+                                       uint64_t *must_precopy,
+                                       uint64_t *can_postcopy)
 {
     DBMSaveState *s = &((DBMState *)opaque)->save;
     SaveBitmapState *dbms;
@@ -784,7 +784,7 @@ static void dirty_bitmap_state_pending(void *opaque,
 
     trace_dirty_bitmap_state_pending(pending);
 
-    *res_postcopy_only += pending;
+    *can_postcopy += pending;
 }
 
 /* First occurrence of this bitmap. It should be created if doesn't exist */

migration/block.c

@@ -853,9 +853,8 @@ static int block_save_complete(QEMUFile *f, void *opaque)
     return 0;
 }
 
-static void block_state_pending(void *opaque,
-                                uint64_t *res_precopy_only,
-                                uint64_t *res_postcopy_only)
+static void block_state_pending(void *opaque, uint64_t *must_precopy,
+                                uint64_t *can_postcopy)
 {
     /* Estimate pending number of bytes to send */
     uint64_t pending;
@@ -876,7 +875,7 @@ static void block_state_pending(void *opaque,
 
     trace_migration_block_state_pending(pending);
     /* We don't do postcopy */
-    *res_precopy_only += pending;
+    *must_precopy += pending;
 }
 
 static int block_load(QEMUFile *f, void *opaque, int version_id)

migration/migration.c

@@ -3863,18 +3863,18 @@ typedef enum {
  */
 static MigIterateState migration_iteration_run(MigrationState *s)
 {
-    uint64_t pend_pre, pend_post;
+    uint64_t must_precopy, can_postcopy;
     bool in_postcopy = s->state == MIGRATION_STATUS_POSTCOPY_ACTIVE;
 
-    qemu_savevm_state_pending_estimate(&pend_pre, &pend_post);
-    uint64_t pending_size = pend_pre + pend_post;
+    qemu_savevm_state_pending_estimate(&must_precopy, &can_postcopy);
+    uint64_t pending_size = must_precopy + can_postcopy;
 
-    trace_migrate_pending_estimate(pending_size, pend_pre, pend_post);
+    trace_migrate_pending_estimate(pending_size, must_precopy, can_postcopy);
 
-    if (pend_pre <= s->threshold_size) {
-        qemu_savevm_state_pending_exact(&pend_pre, &pend_post);
-        pending_size = pend_pre + pend_post;
-        trace_migrate_pending_exact(pending_size, pend_pre, pend_post);
+    if (must_precopy <= s->threshold_size) {
+        qemu_savevm_state_pending_exact(&must_precopy, &can_postcopy);
+        pending_size = must_precopy + can_postcopy;
+        trace_migrate_pending_exact(pending_size, must_precopy, can_postcopy);
     }
 
     if (!pending_size || pending_size < s->threshold_size) {
@@ -3884,7 +3884,7 @@ static MigIterateState migration_iteration_run(MigrationState *s)
     }
 
     /* Still a significant amount to transfer */
-    if (!in_postcopy && pend_pre <= s->threshold_size &&
+    if (!in_postcopy && must_precopy <= s->threshold_size &&
         qatomic_read(&s->start_postcopy)) {
         if (postcopy_start(s)) {
             error_report("%s: postcopy failed to start", __func__);

migration/ram.c

@@ -3489,9 +3489,8 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
     return 0;
 }
 
-static void ram_state_pending_estimate(void *opaque,
-                                       uint64_t *res_precopy_only,
-                                       uint64_t *res_postcopy_only)
+static void ram_state_pending_estimate(void *opaque, uint64_t *must_precopy,
+                                       uint64_t *can_postcopy)
 {
     RAMState **temp = opaque;
     RAMState *rs = *temp;
@@ -3500,15 +3499,14 @@ static void ram_state_pending_estimate(void *opaque,
 
     if (migrate_postcopy_ram()) {
         /* We can do postcopy, and all the data is postcopiable */
-        *res_postcopy_only += remaining_size;
+        *can_postcopy += remaining_size;
     } else {
-        *res_precopy_only += remaining_size;
+        *must_precopy += remaining_size;
     }
 }
 
-static void ram_state_pending_exact(void *opaque,
-                                    uint64_t *res_precopy_only,
-                                    uint64_t *res_postcopy_only)
+static void ram_state_pending_exact(void *opaque, uint64_t *must_precopy,
+                                    uint64_t *can_postcopy)
 {
     RAMState **temp = opaque;
     RAMState *rs = *temp;
@@ -3526,9 +3524,9 @@ static void ram_state_pending_exact(void *opaque,
 
     if (migrate_postcopy_ram()) {
         /* We can do postcopy, and all the data is postcopiable */
-        *res_postcopy_only += remaining_size;
+        *can_postcopy += remaining_size;
     } else {
-        *res_precopy_only += remaining_size;
+        *must_precopy += remaining_size;
     }
 }
 

migration/savevm.c

@@ -1541,13 +1541,13 @@ flush:
  * the result is split into the amount for units that can and
  * for units that can't do postcopy.
  */
-void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
-                                        uint64_t *res_postcopy_only)
+void qemu_savevm_state_pending_estimate(uint64_t *must_precopy,
+                                        uint64_t *can_postcopy)
 {
     SaveStateEntry *se;
 
-    *res_precopy_only = 0;
-    *res_postcopy_only = 0;
+    *must_precopy = 0;
+    *can_postcopy = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (!se->ops || !se->ops->state_pending_estimate) {
@@ -1558,19 +1558,17 @@ void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
                 continue;
             }
         }
-        se->ops->state_pending_estimate(se->opaque,
-                                        res_precopy_only,
-                                        res_postcopy_only);
+        se->ops->state_pending_estimate(se->opaque, must_precopy, can_postcopy);
     }
 }
 
-void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
-                                     uint64_t *res_postcopy_only)
+void qemu_savevm_state_pending_exact(uint64_t *must_precopy,
+                                     uint64_t *can_postcopy)
 {
     SaveStateEntry *se;
 
-    *res_precopy_only = 0;
-    *res_postcopy_only = 0;
+    *must_precopy = 0;
+    *can_postcopy = 0;
 
     QTAILQ_FOREACH(se, &savevm_state.handlers, entry) {
         if (!se->ops || !se->ops->state_pending_exact) {
@@ -1581,9 +1579,7 @@ void qemu_savevm_state_pending_exact(uint64_t *res_precopy_only,
                 continue;
             }
         }
-        se->ops->state_pending_exact(se->opaque,
-                                     res_precopy_only,
-                                     res_postcopy_only);
+        se->ops->state_pending_exact(se->opaque, must_precopy, can_postcopy);
     }
 }
 

migration/savevm.h

@@ -40,10 +40,10 @@ void qemu_savevm_state_cleanup(void);
 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_exact(uint64_t *res_precopy_only,
-                                     uint64_t *res_postcopy_only);
-void qemu_savevm_state_pending_estimate(uint64_t *res_precopy_only,
-                                        uint64_t *res_postcopy_only);
+void qemu_savevm_state_pending_exact(uint64_t *must_precopy,
+                                     uint64_t *can_postcopy);
+void qemu_savevm_state_pending_estimate(uint64_t *must_precopy,
+                                        uint64_t *can_postcopy);
 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);