Re: [PATCH v10 12/14] mm: multi-gen LRU: debugfs interface

[Yu Zhao]

On Mon, Apr 11, 2022 at 8:16 PM Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed,  6 Apr 2022 21:15:24 -0600 Yu Zhao <yuzhao@xxxxxxxxxx> wrote:
>
> > Add /sys/kernel/debug/lru_gen for working set estimation and proactive
> > reclaim. These features are required to optimize job scheduling (bin
> > packing) in data centers [1][2].
>
> debugfs is for ephemeral temp stuf which can and will change or
> disappear at any time.  Anything which is "required" by userspace
> should not be in debufgs.

Right. "required" is probably a poor choice of words. "These
techniques are commonly used to optimize job scheduling" would sound
better.

> Presumably sysfs is the place.  Fully documented and with usage
> examples in the changelog so we can carefully review the proposed
> extensions to Linux's ABI.  Extensions which must be maintained
> unchanged for all time.

Eventually, yes. There still is a long way to go. Rest assured, this
is something Google will keep investing resources on.