migration: Add pss.postcopy_requested status

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>
Message-Id: <20220331150857.74406-4-peterx@redhat.com>
Reviewed-by: Daniel P. Berrangé <berrange@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

diff --git a/migration/ram.c b/migration/ram.c
index 3532f64ecb98cbc835ccefbce85d9b001ed4908d..bfcd45a36e4bee30fd7ded34c55e97811c3db020 100644 (file)
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -414,6 +414,8 @@ 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;
 
@@ -1487,6 +1489,9 @@ 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) {
@@ -1981,6 +1986,7 @@ static bool get_queued_page(RAMState *rs, PageSearchStatus *pss)
          * really rare.
          */
         pss->complete_round = false;
+        pss->postcopy_requested = true;
     }
 
     return !!block;