Mesh is a replacement for maclloc that trys to recover from memory fragmentation.
This video is worth watching: https://www.youtube.com/watch?v=c1UBJbfR-H0.
Install it following the instructions in the README: https://github.com/plasma-umass/Mesh.
You may also need to install libtinfo5.
Compile bitcoind as usual.
Preload libmesh.so and set MALLOCSTATS=1 when running:
MALLOCSTATS=1 LD_PRELOAD=libmesh.so src/bitcoind
....
2020-05-13T00:12:48.988675Z [shutoff] Shutdown: done
MESH COUNT: 46440
Meshed MB (total): 181.4
Meshed pages HWM: 32434
Meshed MB HWM: 126.7
MH Alloc Count: 379875
MH Free Count: 663645
MH High Water Mark: 152451