Re: [PATCH v3 5/6] mm/mglru: use explicit tier range in read_ctrl_pos()

[Lian Wang]

Hi Kairui,

> Replace it with explicit (tier_min, tier_max) parameters using a
> closed [tier_min, tier_max] interval

While touching read_ctrl_pos(), would it make sense to add:

	lockdep_assert_held(&lruvec->lru_lock);

All current callers run under the lruvec lock. read_ctrl_pos() derives the
history slot from min_seq and combines avg_refaulted/avg_total and protected
with the atomic counters, while reset_ctrl_pos() rotates and clears that
state under the same lock and already has this assertion.

Adding the assertion here would document the snapshot contract and catch a
future lockless caller before it can observe fields from different history
epochs.

If I missed an existing lockless caller, or if this is intentionally a
best-effort snapshot, please ignore this suggestion.

Thanks,
Lian