specifying in the kernel command line

[valdis.kletnieks at vt.edu]

On Wed, 04 Apr 2018 11:46:01 +0300, Kevin Wilson said:
> Hello,
> I have an x86_64 host with 4GB of Physical RAM running Fedora 25.
>
> I have a question about hugepages allocation on this host.
> In:
> https://www.kernel.org/doc/Documentation/vm/hugetlbpage.txt
>
> I see that you can use "hugepages=N" kernel parameter (in grub) for
> specifying the number
> of hugepages you want to allocate at boot time.

First off, have you considered transparent hugepages, where the kernel
will auto-coalesce memory allocation of contiguous pages into a hugepage?

> The default hugepage size on this host is 2MB.
>
> For example, I am thinking of using
> hugepagesz=2MB hugepages=4096
> in the kernel command line.

Why?

What are you hoping to accomplish?  (Hint:  Figure out why the
default page size is only 4K rather than 2M - how much I/O do
you need to do per page fault if you have a 2M pagesize)

Do you have a workload that has a good chance of performing better
with hugepages?