Re: [PATCH 12/12] mm/damon/core: add trace point for damos stat per apply interval

Steven Rostedt
2025-12-17T22:47:18Z

On Tue, 16 Dec 2025 00:01:25 -0800
SeongJae Park <sj@kernel.org> wrote:

> + TP_printk("ctx_idx=%u scheme_idx=%u nr_tried=%lu sz_tried=%lu "
> + "nr_applied=%lu sz_tried=%lu sz_ops_filter_passed=%lu "
> + "qt_exceeds=%lu nr_snapshots=%lu",

Nit, but it's been stated that strings should not be broken up because of
the column limit.

> + __entry->context_idx, __entry->scheme_idx,
> + __entry->nr_tried, __entry->sz_tried,
> + __entry->nr_applied, __entry->sz_applied,
> + __entry->sz_ops_filter_passed, __entry->qt_exceeds,
> + __entry->nr_snapshots)
> +);
> +
> TRACE_EVENT(damos_esz,
>
> TP_PROTO(unsigned int context_idx, unsigned int scheme_idx,
> diff --git a/mm/damon/core.c b/mm/damon/core.c
> index 8908aec6670f..68dd2f7acba2 100644
> --- a/mm/damon/core.c
> +++ b/mm/damon/core.c
> @@ -2256,6 +2256,22 @@ static void damos_adjust_quota(struct damon_ctx *c, struct damos *s)
> quota->min_score = score;
> }
>
> +static void damos_trace_stat(struct damon_ctx *c, struct damos *s)
> +{
> + unsigned int cidx = 0, sidx = 0;
> + struct damos *siter;
> +
> + if (!trace_damos_stat_after_apply_interval_enabled())
> + return;

Other than that, from a tracing POV:

Reviewed-by: Steven Rostedt (Google) <rostedt@goodmis.org>

-- Steve

> +
> + damon_for_each_scheme(siter, c) {
> + if (siter == s)
> + break;
> + sidx++;
> + }
> + trace_damos_stat_after_apply_interval(cidx, sidx, &s->stat);
> +}
> +
> static void kdamond_apply_schemes(struct damon_ctx *c)
> {
> struct damon_target *t;
> @@ -2297,6 +2313,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
> (s->apply_interval_us ? s->apply_interval_us :
> c->attrs.aggr_interval) / sample_interval;
> s->last_applied = NULL;
> + damos_trace_stat(c, s);
> }
> mutex_unlock(&c->walk_control_lock);
> }