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From 32ee75b7f4a31d6080e5659e2a0285a046ef1036 Mon Sep 17 00:00:00 2001
From: Juan Quintela <quintela@redhat.com>
Date: Tue, 3 Mar 2020 14:51:34 +0000
Subject: [PATCH 02/18] migration/multifd: clean pages after filling packet

RH-Author: Juan Quintela <quintela@redhat.com>
Message-id: <20200303145143.149290-2-quintela@redhat.com>
Patchwork-id: 94112
O-Subject: [RHEL-AV-8.2.0 qemu-kvm PATCH v2 01/10] migration/multifd: clean pages after filling packet
Bugzilla: 1738451
RH-Acked-by: Laurent Vivier <lvivier@redhat.com>
RH-Acked-by: Peter Xu <peterx@redhat.com>
RH-Acked-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

From: Wei Yang <richardw.yang@linux.intel.com>

This is a preparation for the next patch:

    not use multifd during postcopy.

Without enabling postcopy, everything looks good. While after enabling
postcopy, migration may fail even not use multifd during postcopy. The
reason is the pages is not properly cleared and *old* target page will
continue to be transferred.

After clean pages, migration succeeds.

Signed-off-by: Wei Yang <richardw.yang@linux.intel.com>
Reviewed-by: Juan Quintela <quintela@redhat.com>
Signed-off-by: Juan Quintela <quintela@redhat.com>
(cherry picked from commit eab54aa78ffd9fb7895b20fc2761ee998479489b)
Signed-off-by: Danilo C. L. de Paula <ddepaula@redhat.com>
---
 migration/ram.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/migration/ram.c b/migration/ram.c
index 5078f94..65580e3 100644
--- a/migration/ram.c
+++ b/migration/ram.c
@@ -944,10 +944,10 @@ static int multifd_send_pages(RAMState *rs)
         }
         qemu_mutex_unlock(&p->mutex);
     }
-    p->pages->used = 0;
+    assert(!p->pages->used);
+    assert(!p->pages->block);
 
     p->packet_num = multifd_send_state->packet_num++;
-    p->pages->block = NULL;
     multifd_send_state->pages = p->pages;
     p->pages = pages;
     transferred = ((uint64_t) pages->used) * TARGET_PAGE_SIZE + p->packet_len;
@@ -1129,6 +1129,8 @@ static void *multifd_send_thread(void *opaque)
             p->flags = 0;
             p->num_packets++;
             p->num_pages += used;
+            p->pages->used = 0;
+            p->pages->block = NULL;
             qemu_mutex_unlock(&p->mutex);
 
             trace_multifd_send(p->id, packet_num, used, flags,
-- 
1.8.3.1