From 1c9e86aac83e91498772885f5223e212337a3ff9 Mon Sep 17 00:00:00 2001
From: Laurent Vivier <lvivier@redhat.com>
Date: Thu, 21 Jun 2018 09:45:26 +0200
Subject: [PATCH 075/268] migration: calculate expected_downtime with
 ram_bytes_remaining()

RH-Author: Laurent Vivier <lvivier@redhat.com>
Message-id: <20180621094526.5714-1-lvivier@redhat.com>
Patchwork-id: 80931
O-Subject: [RHEL-7.6 qemu-kvm-rhev PATCH] migration: calculate expected_downtime with ram_bytes_remaining()
Bugzilla: 1564576
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
RH-Acked-by: Thomas Huth <thuth@redhat.com>
RH-Acked-by: David Gibson <dgibson@redhat.com>

From: 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 resonable.

consider to read the remaining ram just after having updated the dirty
pages count later migration_bitmap_sync_range() in migration_bitmap_sync()
and reuse the `remaining` field in ram_counters to hold ram_bytes_remaining()
for calculating expected_downtime.

Reported-by: Michael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: Balamuruhan S <bala24@linux.vnet.ibm.com>
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Message-Id: <20180612085009.17594-2-bala24@linux.vnet.ibm.com>
Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: Dr. David Alan Gilbert <dgilbert@redhat.com>
(cherry picked from commit 650af8907bd567db914b7ce3a7e9df4c323f4619)
Signed-off-by: Laurent Vivier <lvivier@redhat.com>
Signed-off-by: Miroslav Rezanina <mrezanin@redhat.com>
---
 migration/migration.c | 3 +--
 migration/ram.c       | 1 +
 2 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/migration/migration.c b/migration/migration.c
index ef4bb42..43d8a64 100644
--- a/migration/migration.c
+++ b/migration/migration.c
@@ -2239,8 +2239,7 @@ 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 = ram_counters.remaining / bandwidth;
     }
 
     qemu_file_reset_rate_limit(s->to_dst_file);
diff --git a/migration/ram.c b/migration/ram.c
index 0e90efa..00c06b5 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -852,6 +852,7 @@ static void migration_bitmap_sync(RAMState *rs)
     RAMBLOCK_FOREACH(block) {
         migration_bitmap_sync_range(rs, block, 0, block->used_length);
     }
+    ram_counters.remaining = ram_bytes_remaining();
     rcu_read_unlock();
     qemu_mutex_unlock(&rs->bitmap_mutex);
 
-- 
1.8.3.1