Merge pull request #3668 from ceph/wip-compact-container

Optimize memory usage of MDS

Reviewed-by: John Spray <john.spray@redhat.com>
Reviewed-by: Greg Farnum <gfarnum@redhat.com>

diff --cc src/mds/Locker.cc
Simple merge

diff --cc src/mds/MDCache.cc
Simple merge

diff --cc src/mds/Server.cc
Simple merge

diff --cc src/mds/journal.cc
Simple merge