migration/ram: Add tracepoints for ram_save_complete()

Take notes on start/end state of dirty pages for the whole system.

Reviewed-by: Juraj Marcin <jmarcin@redhat.com>
Link: https://lore.kernel.org/r/20250613140801.474264-10-peterx@redhat.com
Signed-off-by: Peter Xu <peterx@redhat.com>
Signed-off-by: Fabiano Rosas <farosas@suse.de>

migration/ram.c

@@ -3290,6 +3290,8 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
     RAMState *rs = *temp;
     int ret = 0;
 
+    trace_ram_save_complete(rs->migration_dirty_pages, 0);
+
     rs->last_stage = !migration_in_colo_state();
 
     WITH_RCU_READ_LOCK_GUARD() {
@@ -3353,6 +3355,9 @@ static int ram_save_complete(QEMUFile *f, void *opaque)
     }
 
     qemu_put_be64(f, RAM_SAVE_FLAG_EOS);
+
+    trace_ram_save_complete(rs->migration_dirty_pages, 1);
+
     return qemu_fflush(f);
 }
 

migration/trace-events

@@ -105,6 +105,7 @@ ram_load_postcopy_loop(int channel, uint64_t addr, int flags) "chan=%d addr=0x%"
 ram_postcopy_send_discard_bitmap(void) ""
 ram_save_page(const char *rbname, uint64_t offset, void *host) "%s: offset: 0x%" PRIx64 " host: %p"
 ram_save_queue_pages(const char *rbname, size_t start, size_t len) "%s: start: 0x%zx len: 0x%zx"
+ram_save_complete(uint64_t dirty_pages, int done) "dirty=%" PRIu64 ", done=%d"
 ram_dirty_bitmap_request(char *str) "%s"
 ram_dirty_bitmap_reload_begin(char *str) "%s"
 ram_dirty_bitmap_reload_complete(char *str) "%s"