Merge pull request #24297 from ukernel/wip-36192

osdc: reduce ObjectCacher's memory fragments

Reviewed-by: Kefu Chai <kchai@redhat.com>
Reviewed-by: Patrick Donnelly <pdonnell@redhat.com>
Reviewed-by: Jason Dillaman <dillaman@redhat.com>

diff --cc src/common/buffer.cc
Simple merge

diff --cc src/include/buffer.h
Simple merge

diff --cc src/osdc/ObjectCacher.cc
Simple merge