[ add Andrew ]
On Thu, Feb 4, 2021 at 6:40 PM Aneesh Kumar K.V
<aneesh.kumar(a)linux.ibm.com> wrote:
Differentiate between hardware not supporting hugepages and user disabling THP
via 'echo never > /sys/kernel/mm/transparent_hugepage/enabled'
For the devdax namespace, the kernel handles the above via the
supported_alignment attribute and failing to initialize the namespace
if the namespace align value is not supported on the platform.
For the fsdax namespace, the kernel will continue to initialize
the namespace. This can result in the kernel creating a huge pte
entry even though the hardware don't support the same.
We do want hugepage support with pmem even if the end-user disabled THP
via sysfs file (/sys/kernel/mm/transparent_hugepage/enabled). Hence
differentiate between hardware/firmware lacking support vs user-controlled
disable of THP and prevent a huge fault if the hardware lacks hugepage
support.
Looks good to me.
Reviewed-by: Dan Williams <dan.j.williams(a)intel.com>
I assume this will go through Andrew.