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-rw-r--r--mm/damon/prmtv-common.c46
1 files changed, 46 insertions, 0 deletions
diff --git a/mm/damon/prmtv-common.c b/mm/damon/prmtv-common.c
index 7e62ee54fb54..92a04f5831d6 100644
--- a/mm/damon/prmtv-common.c
+++ b/mm/damon/prmtv-common.c
@@ -85,3 +85,49 @@ void damon_pmdp_mkold(pmd_t *pmd, struct mm_struct *mm, unsigned long addr)
put_page(page);
#endif /* CONFIG_TRANSPARENT_HUGEPAGE */
}
+
+#define DAMON_MAX_SUBSCORE (100)
+#define DAMON_MAX_AGE_IN_LOG (32)
+
+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;
+
+ 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 coldness of the region */
+ return DAMOS_MAX_SCORE - hotness;
+}