Re: [PATCH v2 1/4] hugetlb: add demote hugetlb page sysfs interfaces

["Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>]

Mike Kravetz <mike.kravetz@oracle.com> writes:

> Two new sysfs files are added to demote hugtlb pages.  These files are
> both per-hugetlb page size and per node.  Files are:
>   demote_size - The size in Kb that pages are demoted to. (read-write)
>   demote - The number of huge pages to demote. (write-only)
>
> By default, demote_size is the next smallest huge page size.  Valid huge
> page sizes less than huge page size may be written to this file.  When
> huge pages are demoted, they are demoted to this size.
>
> Writing a value to demote will result in an attempt to demote that
> number of hugetlb pages to an appropriate number of demote_size pages.
>
> NOTE: Demote interfaces are only provided for huge page sizes if there
> is a smaller target demote huge page size.  For example, on x86 1GB huge
> pages will have demote interfaces.  2MB huge pages will not have demote
> interfaces.

Should we also check if the platform allows for
gigantic_page_runtime_supported() ? 

-aneesh