On Thu, 2022-06-16 at 10:17 +0530, Aneesh Kumar K V wrote: > On 6/16/22 9:15 AM, Wei Xu wrote: > > On Wed, Jun 15, 2022 at 6:11 PM Ying Huang <ying.huang@xxxxxxxxx> wrote: > > > > > > On Tue, 2022-06-14 at 14:56 -0400, Johannes Weiner wrote: > > > > On Tue, Jun 14, 2022 at 01:31:37PM +0530, Aneesh Kumar K V wrote: > > .... > > > > As Jonathan Cameron pointed, we may need the memory tier ID to be > > > stable if possible. I know this isn't a easy task. At least we can > > > make the default memory tier (CPU local DRAM) ID stable (for example > > > make it always 128)? That provides an anchor for users to understand. > > > > One of the motivations of introducing "rank" is to allow memory tier > > ID to be stable, at least for the well-defined tiers such as the > > default memory tier. The default memory tier can be moved around in > > the tier hierarchy by adjusting its rank position relative to other > > tiers, but its device ID can remain the same, e.g. always 1. > > > > With /sys/devices/system/memtier/default_tier userspace will be able query > the default tier details. > Yes. This is a way to address the memory tier ID stability issue too. Anther choice is to make default_tier a symbolic link. Best Regards, Huang, Ying
