[Qemu-devel] [PATCH v2 1/1] migration: calculate expected_downtime with ram_bytes_remaining()

[Balamuruhan S <bala24@linux.vnet.ibm.com>]

expected_downtime value is not accurate with dirty_pages_rate * page_size,
using ram_bytes_remaining would yeild it correct.

Signed-off-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
---
 migration/migration.c | 6 +++---
 migration/migration.h | 1 +
 2 files changed, 4 insertions(+), 3 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index 52a5092add..4d866bb920 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -614,7 +614,7 @@ static void populate_ram_info(MigrationInfo *info, MigrationState *s)
     }
 
     if (s->state != MIGRATION_STATUS_COMPLETED) {
-        info->ram->remaining = ram_bytes_remaining();
+        info->ram->remaining = s->ram_bytes_remaining;
         info->ram->dirty_pages_rate = ram_counters.dirty_pages_rate;
     }
 }
@@ -2227,6 +2227,7 @@ static void migration_update_counters(MigrationState *s,
     transferred = qemu_ftell(s->to_dst_file) - s->iteration_initial_bytes;
     time_spent = current_time - s->iteration_start_time;
     bandwidth = (double)transferred / time_spent;
+    s->ram_bytes_remaining = ram_bytes_remaining();
     s->threshold_size = bandwidth * s->parameters.downtime_limit;
 
     s->mbps = (((double) transferred * 8.0) /
@@ -2237,8 +2238,7 @@ static void migration_update_counters(MigrationState *s,
      * recalculate. 10000 is a small enough number for our purposes
      */
     if (ram_counters.dirty_pages_rate && transferred > 10000) {
-        s->expected_downtime = ram_counters.dirty_pages_rate *
-            qemu_target_page_size() / bandwidth;
+        s->expected_downtime = s->ram_bytes_remaining / bandwidth;
     }
 
     qemu_file_reset_rate_limit(s->to_dst_file);
diff --git a/migration/migration.h b/migration/migration.h
index 8d2f320c48..8584f8e22e 100644
--- a/migration/migration.h
+++ b/migration/migration.h
@@ -128,6 +128,7 @@ struct MigrationState
     int64_t downtime_start;
     int64_t downtime;
     int64_t expected_downtime;
+    int64_t ram_bytes_remaining;
     bool enabled_capabilities[MIGRATION_CAPABILITY__MAX];
     int64_t setup_time;
     /*
-- 
2.14.3