2022-08-29 10:26:30

by Kaixu Xia

Subject: [PATCH] mm/damon: get the hotness from damon_hot_score() in damon_pageout_score()

From: Kaixu Xia <[email protected]>

We can get the hotness value from damon_hot_score() directly in
damon_pageout_score() function and improve the code readability.

Signed-off-by: Kaixu Xia <[email protected]>
---
mm/damon/ops-common.c | 46 ++++++-------------------------------------
1 file changed, 6 insertions(+), 40 deletions(-)

diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
index b1335de200e7..f599838b5f64 100644
--- a/mm/damon/ops-common.c
+++ b/mm/damon/ops-common.c
@@ -88,7 +88,7 @@ void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr)
#define DAMON_MAX_SUBSCORE (100)
#define DAMON_MAX_AGE_IN_LOG (32)

-int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
+int damon_hot_score(struct damon_ctx *c, struct damon_region *r,
struct damos *s)
{
unsigned int max_nr_accesses;
@@ -127,48 +127,14 @@ int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
*/
hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;

- /* Return coldness of the region */
- return DAMOS_MAX_SCORE - hotness;
+ return hotness;
}

-int damon_hot_score(struct damon_ctx *c, struct damon_region *r,
+int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
struct damos *s)
{
- unsigned int max_nr_accesses;
- int freq_subscore;
- unsigned int age_in_sec;
- int age_in_log, age_subscore;
- unsigned int freq_weight = s->quota.weight_nr_accesses;
- unsigned int age_weight = s->quota.weight_age;
- int hotness;
-
- max_nr_accesses = c->aggr_interval / c->sample_interval;
- freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses;
+ int hotness = damon_hot_score(c, r, s);

- age_in_sec = (unsigned long)r->age * c->aggr_interval / 1000000;
- for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec;
- age_in_log++, age_in_sec >>= 1)
- ;
-
- /* If frequency is 0, higher age means it's colder */
- if (freq_subscore == 0)
- age_in_log *= -1;
-
- /*
- * Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG].
- * Scale it to be in [0, 100] and set it as age subscore.
- */
- age_in_log += DAMON_MAX_AGE_IN_LOG;
- age_subscore = age_in_log * DAMON_MAX_SUBSCORE /
- DAMON_MAX_AGE_IN_LOG / 2;
-
- hotness = (freq_weight * freq_subscore + age_weight * age_subscore);
- if (freq_weight + age_weight)
- hotness /= freq_weight + age_weight;
- /*
- * Transform it to fit in [0, DAMOS_MAX_SCORE]
- */
- hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
-
- return hotness;
+ /* Return coldness of the region */
+ return DAMOS_MAX_SCORE - hotness;
}
--
2.27.0

2022-08-29 18:21:43

by SeongJae Park

Subject: Re: [PATCH] mm/damon: get the hotness from damon_hot_score() in damon_pageout_score()

Hi Kaixu,

On Mon, 29 Aug 2022 17:46:06 +0800 [email protected] wrote:

> From: Kaixu Xia <[email protected]>
>
> We can get the hotness value from damon_hot_score() directly in
> damon_pageout_score() function and improve the code readability.
>
> Signed-off-by: Kaixu Xia <[email protected]>

Reviewed-by: SeongJae Park <[email protected]>


Thanks,
SJ

> ---
> mm/damon/ops-common.c | 46 ++++++-------------------------------------
> 1 file changed, 6 insertions(+), 40 deletions(-)
>
> diff --git a/mm/damon/ops-common.c b/mm/damon/ops-common.c
> index b1335de200e7..f599838b5f64 100644
> --- a/mm/damon/ops-common.c
> +++ b/mm/damon/ops-common.c
> @@ -88,7 +88,7 @@ void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr)
> #define DAMON_MAX_SUBSCORE (100)
> #define DAMON_MAX_AGE_IN_LOG (32)
>
> -int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
> +int damon_hot_score(struct damon_ctx *c, struct damon_region *r,
> struct damos *s)
> {
> unsigned int max_nr_accesses;
> @@ -127,48 +127,14 @@ int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
> */
> hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
>
> - /* Return coldness of the region */
> - return DAMOS_MAX_SCORE - hotness;
> + return hotness;
> }
>
> -int damon_hot_score(struct damon_ctx *c, struct damon_region *r,
> +int damon_pageout_score(struct damon_ctx *c, struct damon_region *r,
> struct damos *s)
> {
> - unsigned int max_nr_accesses;
> - int freq_subscore;
> - unsigned int age_in_sec;
> - int age_in_log, age_subscore;
> - unsigned int freq_weight = s->quota.weight_nr_accesses;
> - unsigned int age_weight = s->quota.weight_age;
> - int hotness;
> -
> - max_nr_accesses = c->aggr_interval / c->sample_interval;
> - freq_subscore = r->nr_accesses * DAMON_MAX_SUBSCORE / max_nr_accesses;
> + int hotness = damon_hot_score(c, r, s);
>
> - age_in_sec = (unsigned long)r->age * c->aggr_interval / 1000000;
> - for (age_in_log = 0; age_in_log < DAMON_MAX_AGE_IN_LOG && age_in_sec;
> - age_in_log++, age_in_sec >>= 1)
> - ;
> -
> - /* If frequency is 0, higher age means it's colder */
> - if (freq_subscore == 0)
> - age_in_log *= -1;
> -
> - /*
> - * Now age_in_log is in [-DAMON_MAX_AGE_IN_LOG, DAMON_MAX_AGE_IN_LOG].
> - * Scale it to be in [0, 100] and set it as age subscore.
> - */
> - age_in_log += DAMON_MAX_AGE_IN_LOG;
> - age_subscore = age_in_log * DAMON_MAX_SUBSCORE /
> - DAMON_MAX_AGE_IN_LOG / 2;
> -
> - hotness = (freq_weight * freq_subscore + age_weight * age_subscore);
> - if (freq_weight + age_weight)
> - hotness /= freq_weight + age_weight;
> - /*
> - * Transform it to fit in [0, DAMOS_MAX_SCORE]
> - */
> - hotness = hotness * DAMOS_MAX_SCORE / DAMON_MAX_SUBSCORE;
> -
> - return hotness;
> + /* Return coldness of the region */
> + return DAMOS_MAX_SCORE - hotness;
> }
> --
> 2.27.0
>