Re: RFC: Memory Tiering Kernel Interfaces (v2)

[Tim Chen]

On Thu, 2022-05-12 at 01:15 -0700, Wei Xu wrote:
> 
> I am OK with moving back the memory tier nodelist into node/.  When
> there are more memory tier attributes needed, we can then create the
> memory tier subtree and replace the tier nodelist in node/ with
> symlinks.
> 
> So the revised sysfs interfaces are:
> 
> * /sys/devices/system/node/memory_tierN (read-only)
> 
>   where N = 0, 1, 2
> 
>   Format: node_list
> 
> * /sys/devices/system/node/nodeN/memory_tier (read/write)
> 
>   where N = 0, 1, ...
> 
>   Format: int or empty

This looks good to me.  Just wonder if having just 1 tier
lower than DRAM is sufficient. We could have wide performance
range for such secondary memories and is one tier sufficient for them?

Tim