Huge pages memory allocation (HugeTLB) still at 3 GB even after disabling huge pages in kernel parameters

whskrb

8/4/24, 1:09 AM

I have recently configured my system to allocate 3 GB of my RAM to huge pages using kernel boot parameters. What I did was add the following kernel boot parameters to GRUB:

default_hugepagesz=2M hugepagesz=1G hugepages=3

However, I have since decided that I don't need them anymore, and have tried to disable them. I removed these parameters from GRUB and ran update-grub. However, when I rebooted my system, my RAM was still taken up by the 3 GB I allocated to huge pages. When I check the file /proc/meminfo/, I see the following lines:

HugePages_Total:       0
HugePages_Free:        0
HugePages_Rsvd:        0
HugePages_Surp:        0
Hugepagesize:       2048 kB
Hugetlb:         3145728 kB

I believe these lines indicate that 3 GB of my system's memory is still allocated to Hugetlb, even after removing the kernel parameters. I also have not configured /etc/systctl.conf/ at all to use huge pages, and when I run the sysctl -a command, these lines are included in the output:

vm.nr_hugepages = 0
vm.nr_hugepages_mempolicy = 0
vm.nr_overcommit_hugepages = 0

...which indicate that no memory should have been allocated to huge pages. Lastly, the file /proc/sys/vm/nr_hugepages also reads 0, which again shows that there shouldn't be any huge pages.

So, my question is, how do I disable huge pages?

0 + 1

grub2

kernel

whskrb

8/5/24, 12:51 AM

I think I might know the reason why it's still enabled; I'll test the fix I have in mind real quick and update this post if I figure out the solution.

Elon Musk

I sit in a Tesla and translated this thread with Ai:

EN: Huge pages memory allocation (HugeTLB) still at 3 GB even after disabling huge pages in kernel parameters

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