From 8e7bde615f634a82a44b1f3d293c049fd3ef9ca9 Mon Sep 17 00:00:00 2001 From: SeongJae Park Date: Thu, 31 Oct 2024 11:37:57 -0700 Subject: [PATCH] mm/damon/core: handle zero schemes apply interval 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. Link: https://lkml.kernel.org/r/20241031183757.49610-3-sj@kernel.org Fixes: 42f994b71404 ("mm/damon/core: implement scheme-specific apply interval") Signed-off-by: SeongJae Park Cc: [6.7.x] Signed-off-by: Andrew Morton --- 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 3131a07569e4..ce700e694b63 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) @@ -1622,7 +1622,7 @@ 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) @@ -1642,9 +1642,9 @@ 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; } -- 2.49.0