You can use squeue -u $USER to get all of your currently running job, and then use sstat -j <job-id> to show the details of your job, including an entry representing memory usage.

It's important to note that simply allocating memory via malloc() doesn't mean the system is actually using that memory. Most modern operating systems implement virtual memory management, which loads memory pages on demand. So, when you call malloc(), you're just modifying the page table, and the actual memory isn't allocated until it's accessed.

Before assuming there’s an issue with the system, I recommend carefully reviewing your code to ensure that memory is being used as expected.