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Date:   Mon, 11 Apr 2022 19:16:34 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Yu Zhao <yuzhao@google.com>
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Subject: Re: [PATCH v10 12/14] mm: multi-gen LRU: debugfs interface
Message-Id: <20220411191634.674554d3de2ba37b3db40ca2@linux-foundation.org>
In-Reply-To: <20220407031525.2368067-13-yuzhao@google.com>
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On Wed,  6 Apr 2022 21:15:24 -0600 Yu Zhao <yuzhao@google.com> 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.

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.