On Wed, Feb 20, 2019 at 11:11 PM Dave Hansen <dave.hansen@xxxxxxxxx> wrote: > > On 2/20/19 2:02 PM, Rafael J. Wysocki wrote: > >> diff --git a/drivers/acpi/hmat/Kconfig b/drivers/acpi/hmat/Kconfig > >> index c9637e2e7514..08e972ead159 100644 > >> --- a/drivers/acpi/hmat/Kconfig > >> +++ b/drivers/acpi/hmat/Kconfig > >> @@ -2,6 +2,7 @@ > >> config ACPI_HMAT > >> bool "ACPI Heterogeneous Memory Attribute Table Support" > >> depends on ACPI_NUMA > >> + select HMEM_REPORTING > > If you want to do this here, I'm not sure that defining HMEM_REPORTING > > as a user-selectable option is a good idea. In particular, I don't > > really think that setting ACPI_HMAT without it makes a lot of sense. > > Apart from this, the patch looks reasonable to me. > > I guess the question is whether we would want to allow folks to consume > the HMAT inside the kernel while not reporting it out via > HMEM_REPORTING. We have some in-kernel users of the HMAT lined up like > mitigations for memory-side caches. > > It's certainly possible that folks would want to consume those > mitigations without anything in sysfs. They might not even want or need > NUMA support itself, for instance. > > So, what should we do? > > config HMEM_REPORTING > bool # no user-visible prompt > default y if ACPI_HMAT > > So folks can override in their .config, but they don't see a prompt? Maybe it would be better to make HMEM_REPORTING do "select ACPI_HMAT if ACPI". The mitigations could then do that too if they depend on HMAT and ACPI_HMAT need not be user-visible at all.
