Ray pinned_in_memory issue

[mattmcdermott]

Currently the Enumerator classes have a memory leak issue, where after running enumerate(), the arguments to the react() function remain pinned in memory (description: "deserialize task arg"). I have investigated this thoroughly but am currently unable to figure out why the arguments are getting pinned in memory. I have also, unfortunately, found no simple way to clear them.

======== Object references status: 2022-09-08 17:25:02.664419 ========
Grouping by node address...        Sorting by object size...        Display allentries per group...


--- Summary for node address: 127.0.0.1 ---
Mem Used by Objects  Local References  Pinned        Used by task   Captured in Objects  Actor Handles
356.0 B              0, (0.0 B)        12, (356.0 B)  0, (0.0 B)     0, (0.0 B)           0, (0.0 B)

--- Object references for node address: 127.0.0.1 ---
IP Address       PID    Type    Call Site               Status          Size    Reference Type      Object Ref
127.0.0.1        61641  Worker  (deserialize task arg)  -               10.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff010000006b000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               10.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff010000006e000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               10.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff010000006a000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               10.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff010000006f000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               10.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff010000006d000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               10.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff010000006c000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               20.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff0100000068000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               22.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff0100000069000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               47.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff0100000067000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               47.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff0100000064000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               47.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff0100000065000000
                                 rxn_network.enumerato
                                rs.basic._react

127.0.0.1        61641  Worker  (deserialize task arg)  -               113.0 B  PINNED_IN_MEMORY    00ffffffffffffffffffffffffffffffffffffff0100000066000000
                                 rxn_network.enumerato
                                rs.basic._react

To record callsite information for each ObjectRef created, set env variable RAY_record_ref_creation_sites=1

--- Aggregate object store stats across all nodes ---
Plasma memory usage 0 MiB, 12 objects, 0.0% full, 0.0% needed
Objects consumed by Ray tasks: 0 MiB.