Re: [PATCH v2 1/4] mm/hugetlb: fix the inconsistency of /proc/sys/vm/nr_huge_pages

[David Hildenbrand <david@redhat.com>]

On 06.08.23 09:48, Xueshi Hu wrote:
> There are currently three 'nr_hugepages' used to export the number of huge
> pages:
> 1. /proc/sys/vm/nr_hugepages
> 2. /sys/devices/system/node/node0/hugepages/hugepages-2048kB/nr_hugepages
> 3. /sys/kernel/mm/hugepages/hugepages-2048kB/nr_hugepages
> 
> For consistency, all three 'nr_hugepages' should return the total number
> of huge pages. When written, the number of persistent huge pages will be
> adjusted to the specified value.
> 
> But, /proc/sys/vm/nr_hugepages returns the number of persistent huge
> pages.
> 

But that's documented behavior, no?

Documentation/admin-guide/mm/hugetlbpage.rst

``/proc/sys/vm/nr_hugepages`` indicates the current number of "persistent" huge
pages in the kernel's huge page pool.  "Persistent" huge pages will be
returned to the huge page pool when freed by a task.  A user with root
privileges can dynamically allocate more or free some persistent huge pages
by increasing or decreasing the value of ``nr_hugepages``.

-- 
Cheers,

David / dhildenb