[PATCH] mm/damon: Remove duplicate attrs.intervals_goal at the damon_stat_build_ctx()

[PATCH] mm/damon: Remove duplicate attrs.intervals_goal at the damon_stat_build_ctx()

[Jung-JaeJoon]

The damon_stat_build_ctx() function sets the values
of attrs.intervals_goal structure members.
These values are applied to damon_ctx in damon_set_attrs().
However, It is resetting the values that were already applied previously
to the same values.
I suggest removing this code as it constitutes duplicate execution.
Please check the modified code below:

Signed-off-by: Jung-JaeJoon <rgbi3307@gmail.com>
---
 mm/damon/stat.c | 8 --------
 1 file changed, 8 deletions(-)

diff --git a/mm/damon/stat.c b/mm/damon/stat.c
index bf8626859902..51dd29685915 100644
--- a/mm/damon/stat.c
+++ b/mm/damon/stat.c
@@ -173,14 +173,6 @@ static struct damon_ctx *damon_stat_build_ctx(void)
 	if (damon_set_attrs(ctx, &attrs))
 		goto free_out;
 
-	/*
-	 * auto-tune sampling and aggregation interval aiming 4% DAMON-observed
-	 * accesses ratio, keeping sampling interval in [5ms, 10s] range.
-	 */
-	ctx->attrs.intervals_goal = (struct damon_intervals_goal) {
-		.access_bp = 400, .aggrs = 3,
-		.min_sample_us = 5000, .max_sample_us = 10000000,
-	};
 	if (damon_select_ops(ctx, DAMON_OPS_PADDR))
 		goto free_out;
 
-- 
2.43.0

Re: [PATCH] mm/damon: Remove duplicate attrs.intervals_goal at the damon_stat_build_ctx()

[SeongJae Park]

+ damon@lists.linux.dev

Please Cc damon@lists.linux.dev for DAMON patches from next time.

On Wed,  3 Dec 2025 12:33:48 +0900 Jung-JaeJoon <rgbi3307@gmail.com> wrote:

> The damon_stat_build_ctx() function sets the values
> of attrs.intervals_goal structure members.
> These values are applied to damon_ctx in damon_set_attrs().
> However, It is resetting the values that were already applied previously
> to the same values.
> I suggest removing this code as it constitutes duplicate execution.

Thank you for finding and fixing this!

> Please check the modified code below:

The above sentence is not needed for normal patch descriptions.  Please drop
it.

Also, I think the subject could be better describe this change, e.g.,

mm/damon/stat: deduplicate intervals_goal setup in damon_stat_build_ctx()

Could you please make the above suggested changes to this patch and resend the
modified version as v2?

> 
> Signed-off-by: Jung-JaeJoon <rgbi3307@gmail.com>

If you agree to my above trivial suggestions and make the requested changes,
please feel free to add below on the v2 patch.

Reviewed-by: SeongJae Park <sj@kernel.org>

> ---
>  mm/damon/stat.c | 8 --------
>  1 file changed, 8 deletions(-)
> 
> diff --git a/mm/damon/stat.c b/mm/damon/stat.c
> index bf8626859902..51dd29685915 100644
> --- a/mm/damon/stat.c
> +++ b/mm/damon/stat.c
> @@ -173,14 +173,6 @@ static struct damon_ctx *damon_stat_build_ctx(void)
>  	if (damon_set_attrs(ctx, &attrs))
>  		goto free_out;
>  
> -	/*
> -	 * auto-tune sampling and aggregation interval aiming 4% DAMON-observed
> -	 * accesses ratio, keeping sampling interval in [5ms, 10s] range.
> -	 */
> -	ctx->attrs.intervals_goal = (struct damon_intervals_goal) {
> -		.access_bp = 400, .aggrs = 3,
> -		.min_sample_us = 5000, .max_sample_us = 10000000,
> -	};
>  	if (damon_select_ops(ctx, DAMON_OPS_PADDR))
>  		goto free_out;
>  
> -- 
> 2.43.0


Thanks,
SJ

[...]

Re: [PATCH] mm/damon: Remove duplicate attrs.intervals_goal at the damon_stat_build_ctx()

[JaeJoon Jung]

Hi, SeongJae Park,
Thank you for your kind reply.
I will send you the v2 patch incorporating the advice you provided above.
Thanks.

On Wed, 3 Dec 2025 at 13:27, SeongJae Park <sj@kernel.org> wrote:
>
> + damon@lists.linux.dev
>
> Please Cc damon@lists.linux.dev for DAMON patches from next time.
>
> On Wed,  3 Dec 2025 12:33:48 +0900 Jung-JaeJoon <rgbi3307@gmail.com> wrote:
>
> > The damon_stat_build_ctx() function sets the values
> > of attrs.intervals_goal structure members.
> > These values are applied to damon_ctx in damon_set_attrs().
> > However, It is resetting the values that were already applied previously
> > to the same values.
> > I suggest removing this code as it constitutes duplicate execution.
>
> Thank you for finding and fixing this!
>
> > Please check the modified code below:
>
> The above sentence is not needed for normal patch descriptions.  Please drop
> it.
>
> Also, I think the subject could be better describe this change, e.g.,
>
> mm/damon/stat: deduplicate intervals_goal setup in damon_stat_build_ctx()
>
> Could you please make the above suggested changes to this patch and resend the
> modified version as v2?
>
> >
> > Signed-off-by: Jung-JaeJoon <rgbi3307@gmail.com>
>
> If you agree to my above trivial suggestions and make the requested changes,
> please feel free to add below on the v2 patch.
>
> Reviewed-by: SeongJae Park <sj@kernel.org>
>
> > ---
> >  mm/damon/stat.c | 8 --------
> >  1 file changed, 8 deletions(-)
> >
> > diff --git a/mm/damon/stat.c b/mm/damon/stat.c
> > index bf8626859902..51dd29685915 100644
> > --- a/mm/damon/stat.c
> > +++ b/mm/damon/stat.c
> > @@ -173,14 +173,6 @@ static struct damon_ctx *damon_stat_build_ctx(void)
> >       if (damon_set_attrs(ctx, &attrs))
> >               goto free_out;
> >
> > -     /*
> > -      * auto-tune sampling and aggregation interval aiming 4% DAMON-observed
> > -      * accesses ratio, keeping sampling interval in [5ms, 10s] range.
> > -      */
> > -     ctx->attrs.intervals_goal = (struct damon_intervals_goal) {
> > -             .access_bp = 400, .aggrs = 3,
> > -             .min_sample_us = 5000, .max_sample_us = 10000000,
> > -     };
> >       if (damon_select_ops(ctx, DAMON_OPS_PADDR))
> >               goto free_out;
> >
> > --
> > 2.43.0
>
>
> Thanks,
> SJ
>
> [...]