Ceph » Messengers

Starting in the thread at http://lists.ceph.com/pipermail/ceph-users-ceph.com/2018-September/029780.html, and continuing on at http://lists.ceph.com/pipermail/ceph-users-ceph.com/2018-September/029783.html

The key claims (which appear accurate):

We can see that the memory is allocated in AsyncConnection::process,
precisely here:
https://github.com/ceph/ceph/blob/master/src/msg/async/AsyncConnection.cc#L614

>From my understanding - I have never read ceph code before, so my
understanding might be flawed - this code is allocating a buffer to store
the data contained in the message received from a ceph node and adding it
to a buffers list `data_buf`.
Note that this list of buffers is per AsyncConnection, that's important.

Unfortunately, looking through the file shows that `data_buf` only gets
cleared here:
https://github.com/ceph/ceph/blob/master/src/msg/async/AsyncConnection.cc#L477
when it transitions to the STATE_OPEN_MESSAGE_HEADER state, IIUC only
occurs when it starts receiving a new CEPH_MSGR_TAG_MSG message.