Is it safe to use LD_PRELOAD to load a custom malloc library when running the OpenJDK?

[기준]

Hello everyone, hope you're doing well!

I have a question, and I’m hoping this is the right place to ask. If it's
not, I’d appreciate it if someone could point me to the correct mailing
list.

Our team is heavily using JNI C++ code for computations that involve
frequent object allocations and deallocations. To optimize these memory
operations, we tested using jemalloc as a replacement for glibc, and
observed huge improvements in performance metrics.

We're currently using LD_PRELOAD to load the jemalloc library when
launching the JVM, so that all memory allocation and deallocation requests
are handled by jemalloc. However, I'm wondering if this approach could lead
to any unexpected issues, since it would also take the JVM's memory
allocation requests as well.

>From what I understand, heap allocations in the JVM don't use malloc
directly, as they rely on optimized assembly code or the JVM's internal
memory management system. Some folks on the internet have mentioned that
the JVM might have a custom malloc implementation designed specifically for
its use, preloading jemalloc may cause symbol conflicts. However, I haven't
been able to find any code supporting that hypothesis.

*My question is: is it safe to use LD_PRELOAD to load a custom malloc
library, like jemalloc, when running the JVM, at least with OpenJDK?*



Thank you in advance.

Dooyong Kim
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