I am wondering, did you ever look at tuning MALLOC_ARENA_MAX? This sort of constant consumption of memory is fairly well aligned to the default tuning of MALLOC

I am wondering, did you ever look at tuning MALLOC_ARENA_MAX? This sort of constant consumption of memory is fairly well aligned to the default tuning of MALLOC_ARENA_MAX, which is 8 * nproc. We've just tuned it for a java-based app which was also stuck in OOMkill hell, and this has completely resolved the situation (MALLOC_ARENA_MAX=2).