From: SeongJae Park <sj@kernel.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: SeongJae Park <sj@kernel.org>,
"# 5 . 16 . x" <stable@vger.kernel.org>,
damon@lists.linux.dev, linux-kernel@vger.kernel.org,
linux-mm@kvack.org
Subject: [PATCH] mm/damon/core: make charge_addr_from aware of end-address exclusivity
Date: Mon, 27 Apr 2026 21:29:40 -0700 [thread overview]
Message-ID: <20260428042942.118230-1-sj@kernel.org> (raw)
DAMON region end address is exclusive one, but charge_addr_from is
assigned assuming the end address is inclusive. As a result, DAMOS
action to next up to min_region_sz memory can be skipped. This is quite
negligible user impact. But, the bug is a bug that can be very simply
fixed. Fix the wrong assignment to respect the exclusiveness of the
address.
The issue was discovered [1] by Sashiko.
[1] https://lore.kernel.org/20260428032324.115663-1-sj@kernel.org
Fixes: 50585192bc2e ("mm/damon/schemes: skip already charged targets and regions")
Cc: <stable@vger.kernel.org> # 5.16.x
Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/core.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 278594847cf94..37c9a40d0577b 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2107,7 +2107,7 @@ static void damos_apply_scheme(struct damon_ctx *c, struct damon_target *t,
if (damos_quota_is_set(quota) &&
quota->charged_sz >= quota->esz) {
quota->charge_target_from = t;
- quota->charge_addr_from = r->ar.end + 1;
+ quota->charge_addr_from = r->ar.end;
}
}
if (s->action != DAMOS_STAT)
base-commit: 986c714ac6faa9750e15ccaec72ff2823c96a5c6
--
2.47.3
reply other threads:[~2026-04-28 4:29 UTC|newest]
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