node only using half of the available memory #64793

Version

26.5.0

Platform

Debian Bookworm

Subsystem

No response

What steps will reproduce the bug?

docker run --rm -it --memory=1G --memory-swap=1G node:26-bookworm-slim bash
root@0e03ab5e67ef:/# node -e 'const v8 = require("v8"); console.log(v8.getHeapStatistics());'
{
total_heap_size: 5115904,
total_heap_size_executable: 262144,
total_physical_size: 5115904,
total_available_size: 559355992,
used_heap_size: 4248992,
heap_size_limit: 562036736,
malloced_memory: 163928,
peak_malloced_memory: 57488,
does_zap_garbage: 0,
number_of_native_contexts: 1,
number_of_detached_contexts: 0,
total_global_handles_size: 12360,
used_global_handles_size: 2400,
external_memory: 1855673,
total_allocated_bytes: 7377904
}

How often does it reproduce? Is there a required condition?

Always

What is the expected behavior? Why is that the expected behavior?

All memory used

What do you see instead?

Half of the memory used

Additional information

Didn't realize that #35573 was going to be closed since it's still an issue