If you assign 95% of the memory to postgres, then yes, it is realistic for page-table to grow several GBs under long and heavy workloads so machine will eventua

If you assign 95% of the memory to postgres, then yes, it is realistic for page-table to grow several GBs under long and heavy workloads so machine will eventually run into an OOM, especially if you use vm.overcommit_memory = 2 (never overcommit). Mitigating the OOM by switching to hugepages may suggest that you're running a kernel with the optimized page-table hugepage handling because of which there are less page-table entries and consequently the whole page-table ends up being smaller. Currently, I have no other explanation.