Bug 177811

Summary:	vm.nr_hugepages not allocating memory after setting to 0
Product:	Other	Reporter:	andrei.grg
Component:	Other	Assignee:	other_other
Status:	NEW ---
Severity:	normal
Priority:	P1
Hardware:	x86-64
OS:	Linux
Kernel Version:	4.7.6	Subsystem:
Regression:	No	Bisected commit-id:

Description andrei.grg 2016-10-17 09:47:04 UTC

Steps to reproduce:

- Use 1GB pagefiles.
- echo 9 > /proc/sys/vm/nr_hugepages
- check that the 9GB memory is now reserved, and it should.
- echo 0 > /proc/sys/vm/nr_hugepages
- check that the 9GB reservation has beed freed, and it should.
- echo 9 > /proc/sys/vm/nr_hugepages
- check that the 9GB memory is reserved, and it's not. (or it reserves less.)

More info: Performing these steps the memory reserved was less and less as 9GB until no reservation was made anymore at all. It can also be the case that after the free-up it allocates only around 1GB and then it stops.