This boolean flag shows whether the current page during migration is triggered
by postcopy or not.  Then in ram_save_host_page() and deeper stack we'll be
able to have a reference on the priority of this page.

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Peter Xu <peterx@redhat.com>
---
 migration/ram.c | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/migration/ram.c b/migration/ram.c
index 25a3ab5150..1ed70b17d7 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -413,6 +413,8 @@ struct PageSearchStatus {
     unsigned long page;
     /* Set once we wrap around */
     bool         complete_round;
+    /* Whether current page is explicitly requested by postcopy */
+    bool         postcopy_requested;
 };
 typedef struct PageSearchStatus PageSearchStatus;
 
@@ -1486,6 +1488,9 @@ retry:
  */
 static bool find_dirty_block(RAMState *rs, PageSearchStatus *pss, bool *again)
 {
+    /* This is not a postcopy requested page */
+    pss->postcopy_requested = false;
+
     pss->page = migration_bitmap_find_dirty(rs, pss->block, pss->page);
     if (pss->complete_round && pss->block == rs->last_seen_block &&
         pss->page >= rs->last_page) {
@@ -1980,6 +1985,7 @@ static bool get_queued_page(RAMState *rs, PageSearchStatus *pss)
          * really rare.
          */
         pss->complete_round = false;
+        pss->postcopy_requested = true;
     }
 
     return !!block;
-- 
2.32.0