DAMON's logics to determine if this is the time to apply damos schemes
assumes next_apply_sis is always set larger than current
passed_sample_intervals. And therefore assume continuously incrementing
passed_sample_intervals will make it reaches to the next_apply_sis in
future. The logic hence does apply the scheme and update next_apply_sis
only if passed_sample_intervals is same to next_apply_sis.
If Schemes apply interval is set as zero, however, next_apply_sis is set
same to current passed_sample_intervals, respectively. And
passed_sample_intervals is incremented before doing the next_apply_sis
check. Hence, next_apply_sis becomes larger than next_apply_sis, and
the logic says it is not the time to apply schemes and update
next_apply_sis. In other words, DAMON stops applying schemes until
passed_sample_intervals overflows.
Based on the documents and the common sense, a reasonable behavior for
such inputs would be applying the schemes for every sampling interval.
Handle the case by removing the assumption.
Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval")
Cc: <stable@xxxxxxxxxxxxxxx> # 6.7.x
Signed-off-by: SeongJae Park <sj@xxxxxxxxxx>
---
mm/damon/core.c | 8 ++++----
1 file changed, 4 insertions(+), 4 deletions(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 931526fb2d2e..511c3f61ab44 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1412,7 +1412,7 @@ static void damon_do_apply_schemes(struct damon_ctx *c,
damon_for_each_scheme(s, c) {
struct damos_quota *quota = &s->quota;
- if (c->passed_sample_intervals != s->next_apply_sis)
+ if (c->passed_sample_intervals < s->next_apply_sis)
continue;
if (!s->wmarks.activated)
@@ -1636,7 +1636,7 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
bool has_schemes_to_apply = false;
damon_for_each_scheme(s, c) {
- if (c->passed_sample_intervals != s->next_apply_sis)
+ if (c->passed_sample_intervals < s->next_apply_sis)
continue;
if (!s->wmarks.activated)
@@ -1656,9 +1656,9 @@ static void kdamond_apply_schemes(struct damon_ctx *c)
}
damon_for_each_scheme(s, c) {
- if (c->passed_sample_intervals != s->next_apply_sis)
+ if (c->passed_sample_intervals < s->next_apply_sis)
continue;
- s->next_apply_sis +=
+ s->next_apply_sis = c->passed_sample_intervals +
(s->apply_interval_us ? s->apply_interval_us :
c->attrs.aggr_interval) / sample_interval;
}
--
2.39.5
