ram: Move dirty_pages_rate to RAMState

Treat it like the rest of ram stats counters.  Export its value the
same way.  As an added bonus, no more MigrationState used in
migration_bitmap_sync();

Signed-off-by: Juan Quintela <quintela@redhat.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Reviewed-by: Peter Xu <peterx@redhat.com>

--

Again, dave was the one reviewing it

2 files changed, 12 insertions, 7 deletions

diff --git a/migration/migration.c b/migration/migration.c
index dcf9b94..e430aec 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -661,7 +661,7 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s)
 
     if (s->state != MIGRATION_STATUS_COMPLETED) {
         info->ram->remaining = ram_bytes_remaining();
-        info->ram->dirty_pages_rate = s->dirty_pages_rate;
+        info->ram->dirty_pages_rate = ram_dirty_pages_rate();
     }
 }
 
@@ -1117,7 +1117,6 @@ MigrationState *migrate_init(const MigrationParams *params)
     s->mbps = 0.0;
     s->downtime = 0;
     s->expected_downtime = 0;
-    s->dirty_pages_rate = 0;
     s->setup_time = 0;
     s->start_postcopy = false;
     s->postcopy_after_devices = false;
@@ -2007,8 +2006,8 @@ static void *migration_thread(void *opaque)
                                       bandwidth, max_size);
             /* if we haven't sent anything, we don't want to recalculate
                10000 is a small enough number for our purposes */
-            if (s->dirty_pages_rate && transferred_bytes > 10000) {
-                s->expected_downtime = s->dirty_pages_rate *
+            if (ram_dirty_pages_rate() && transferred_bytes > 10000) {
+                s->expected_downtime = ram_dirty_pages_rate() *
                     (1ul << qemu_target_page_bits()) / bandwidth;
             }
 
diff --git a/migration/ram.c b/migration/ram.c
index ef4f508..c5240eb 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -212,6 +212,8 @@ struct RAMState {
     uint64_t migration_dirty_pages;
     /* total number of bytes transferred */
     uint64_t bytes_transferred;
+    /* number of dirtied pages in the last second */
+    uint64_t dirty_pages_rate;
     /* protects modification of the bitmap */
     QemuMutex bitmap_mutex;
     /* Ram Bitmap protected by RCU */
@@ -276,6 +278,11 @@ uint64_t ram_dirty_sync_count(void)
     return ram_state.bitmap_sync_count;
 }
 
+uint64_t ram_dirty_pages_rate(void)
+{
+    return ram_state.dirty_pages_rate;
+}
+
 /* used by the search for pages to send */
 struct PageSearchStatus {
     /* Current block being searched */
@@ -666,7 +673,6 @@ uint64_t ram_pagesize_summary(void)
 static void migration_bitmap_sync(RAMState *rs)
 {
     RAMBlock *block;
-    MigrationState *s = migrate_get_current();
     int64_t end_time;
     uint64_t bytes_xfer_now;
 
@@ -705,7 +711,7 @@ static void migration_bitmap_sync(RAMState *rs)
                throttling */
             bytes_xfer_now = ram_bytes_transferred();
 
-            if (s->dirty_pages_rate &&
+            if (rs->dirty_pages_rate &&
                (rs->num_dirty_pages_period * TARGET_PAGE_SIZE >
                    (bytes_xfer_now - rs->bytes_xfer_prev) / 2) &&
                (rs->dirty_rate_high_cnt++ >= 2)) {
@@ -726,7 +732,7 @@ static void migration_bitmap_sync(RAMState *rs)
             rs->iterations_prev = rs->iterations;
             rs->xbzrle_cache_miss_prev = rs->xbzrle_cache_miss;
         }
-        s->dirty_pages_rate = rs->num_dirty_pages_period * 1000
+        rs->dirty_pages_rate = rs->num_dirty_pages_period * 1000
             / (end_time - rs->time_last_bitmap_sync);
         rs->time_last_bitmap_sync = end_time;
         rs->num_dirty_pages_period = 0;