Re: [PATCH 2/3] mm/lru_gen: add configuration option to select debugfs/procfs for lru_gen

Yuanchu Xie
2025-12-01T21:35:22Z

On Thu, Nov 27, 2025 at 8:54 PM Zicheng Wang <wangzicheng@honor.com> wrote:
>
> Signed-off-by: Zicheng Wang <wangzicheng@honor.com>
> ---
> mm/Kconfig | 10 ++++++++++
> 1 file changed, 10 insertions(+)
>
> diff --git a/mm/Kconfig b/mm/Kconfig
> index e443fe8cd..be7efa794 100644
> --- a/mm/Kconfig
> +++ b/mm/Kconfig
> @@ -1325,6 +1325,16 @@ config LRU_GEN_STATS
> config LRU_GEN_WALKS_MMU
> def_bool y
> depends on LRU_GEN && ARCH_HAS_HW_PTE_YOUNG
> +
> +config LRU_GEN_PROCFS_CTRL
> + bool "Move lru_gen files from debugfs to procfs"
> + depends on LRU_GEN && PROC_FS
> + help
> + Move lru_gen management from debugfs to procfs (/proc/lru_gen).
> + This production-ready feature provides critical memory reclaim
> + prediction and control. It is no longer experimental.
> + The migration ensures availability in commercial products where
> + debugfs may be disabled.
Hi Zicheng,

A config option determining where LRU_gen files reside creates a
fragile procfs interface. Consider adding a similar interface with
less implementation detail to /sys/kernel/mm/lru_gen/ if the goal is
to stabilize the debugfs APIs.

If the goal is to proactively age lruvecs that have been at
MIN_NR_GENS for some time/events/etc, is it possible to integrate this
into the kernel and avoid leaking MGLRU implementation details into
userspace?

Thanks,
Yuanchu