Re: [PATCH] mm/damon/core: skip aging from repeated aggressive merging

[SJ Park <sj@kernel.org>]

On Sun, 12 Jul 2026 09:54:30 -0700 SJ Park <sj@kernel.org> wrote:

> The number of DAMON regions could temporarily exceed the user-defined
> maximum number of regions limit for corner cases.  For example, users
> could lower the limit via runtime parameters update.  For such a case,
> kdamond_merge_regions() repeats merging regions in the case doubling the
> merge threshold.  The repeated merge operation could update the age of
> regions multiple times.  This corrupts the monitoring results.  Fix the
> issue by asking the merge operation to skip aging for the corner case.
> 
> The user impact is degradation of the monitoring quality.  The impact
> should be mild, since the degradation is only temporal, and it is not
> common to happen in realistic setups.

Sashiko found no blocker for this patch.  Sashiko sent findings to damon@
mailing list [1], and I replied.  Please read those for details.

[1] https://lore.kernel.org/damon/


Thanks,
SJ

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