Comment 3 for bug 1865011

Reviewed: https://review.opendev.org/710250
Committed: https://git.openstack.org/cgit/openstack/cinder/commit/?id=69462315bc8416bd02ebd6085f0cfc141cfd8877
Submitter: Zuul
Branch: master

commit 69462315bc8416bd02ebd6085f0cfc141cfd8877
Author: Gorka Eguileor <email address hidden>
Date: Thu Feb 27 14:04:13 2020 +0100

    ChunkedBackupDriver: Freeing memory on restore

    When restoring many backups, the backup service uses a lot of memory and
    when we do many concurrent restores the backup service ends up getting
    killed becase the system runs out of memory.

    This patch reduces the ref count to the data as soon as possible to let
    Python garbage collect it instead of hogging it for the whole chunk
    restore.

    Related-Bug: #1865011
    Change-Id: I942d9d8b3976232ae1cf82b698fb27285fbef13a