Commit 650af890 authored by Balamuruhan S's avatar Balamuruhan S Committed by Dr. David Alan Gilbert
Browse files

migration: calculate expected_downtime with ram_bytes_remaining() 



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: default avatarMichael Roth <mdroth@linux.vnet.ibm.com>
Signed-off-by: default avatarBalamuruhan S <bala24@linux.vnet.ibm.com>
Signed-off-by: default avatarLaurent Vivier <lvivier@redhat.com>
Message-Id: <20180612085009.17594-2-bala24@linux.vnet.ibm.com>
Reviewed-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
Signed-off-by: default avatarDr. David Alan Gilbert <dgilbert@redhat.com>
parent e03a34f8

migration/migration.c

+1 −2
Original line number Diff line number Diff line
@@ -2746,8 +2746,7 @@ 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);

migration/ram.c

+1 −0
Original line number Diff line number Diff line
@@ -1180,6 +1180,7 @@ static void migration_bitmap_sync(RAMState *rs) 
    RAMBLOCK_FOREACH_MIGRATABLE(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);