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Message-Id: <20250628165144.55528-2-sj@kernel.org>
Date: Sat, 28 Jun 2025 09:51:34 -0700
From: SeongJae Park <sj@...nel.org>
To:
Cc: SeongJae Park <sj@...nel.org>,
Andrew Morton <akpm@...ux-foundation.org>,
damon@...ts.linux.dev,
kernel-team@...a.com,
linux-kernel@...r.kernel.org,
linux-mm@...ck.org
Subject: [RFC PATCH 01/11] mm/damon/core: introduce [in]active memory ratio damos quota goal metric
DAMOS_LRU_[DE]PRIO are DAMOS actions for making balance of active and
inactive memory size. There is no appripriate DAMOS quota auto-tuning
target metric for the use case. Add two new DAMOS quota goal metrics
for the purpose, namely DAMOS_QUOTA_[IN]ACTIVE_MEM_BP. Those weill
represent the ratio of [in]active memory to total (inactive + active)
memory. Hence, users will be able to ask DAMON to, for example, "find
hot and cold memory, and move pages of those to active and inactive LRU
lists, adjusting the hot/cold thresholds aiming 50:50 active:inactive
memory ratio."
Signed-off-by: SeongJae Park <sj@...nel.org>
---
include/linux/damon.h | 4 ++++
mm/damon/core.c | 22 ++++++++++++++++++++++
2 files changed, 26 insertions(+)
diff --git a/include/linux/damon.h b/include/linux/damon.h
index 517f48ffe782..c2fc6c8cbbe4 100644
--- a/include/linux/damon.h
+++ b/include/linux/damon.h
@@ -179,6 +179,8 @@ enum damos_action {
* @DAMOS_QUOTA_SOME_MEM_PSI_US: System level some memory PSI in us.
* @DAMOS_QUOTA_NODE_MEM_USED_BP: MemUsed ratio of a node.
* @DAMOS_QUOTA_NODE_MEM_FREE_BP: MemFree ratio of a node.
+ * @DAMOS_QUOTA_ACTIVE_MEM_BP: Active to [in]active memory ratio.
+ * @DAMOS_QUOTA_INACTIVE_MEM_BP: Inactive to [in]active memory ratio.
* @NR_DAMOS_QUOTA_GOAL_METRICS: Number of DAMOS quota goal metrics.
*
* Metrics equal to larger than @NR_DAMOS_QUOTA_GOAL_METRICS are unsupported.
@@ -188,6 +190,8 @@ enum damos_quota_goal_metric {
DAMOS_QUOTA_SOME_MEM_PSI_US,
DAMOS_QUOTA_NODE_MEM_USED_BP,
DAMOS_QUOTA_NODE_MEM_FREE_BP,
+ DAMOS_QUOTA_ACTIVE_MEM_BP,
+ DAMOS_QUOTA_INACTIVE_MEM_BP,
NR_DAMOS_QUOTA_GOAL_METRICS,
};
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 02493d71460c..88ffc826a118 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2027,6 +2027,23 @@ static __kernel_ulong_t damos_get_node_mem_bp(
}
#endif
+/*
+ * Returns LRU-active memory to LRU-inactive memory size ratio.
+ */
+static unsigned int damos_get_in_active_mem_bp(bool active_ratio)
+{
+ unsigned long active, inactive, total;
+
+ /* This should align with /proc/meminfo output */
+ active = global_node_page_state(NR_LRU_BASE + LRU_ACTIVE_ANON) +
+ global_node_page_state(NR_LRU_BASE + LRU_ACTIVE_FILE);
+ inactive = global_node_page_state(NR_LRU_BASE + LRU_INACTIVE_ANON) +
+ global_node_page_state(NR_LRU_BASE + LRU_INACTIVE_FILE);
+ total = active + inactive;
+ if (active_ratio)
+ return active * 10000 / total;
+ return inactive * 10000 / total;
+}
static void damos_set_quota_goal_current_value(struct damos_quota_goal *goal)
{
@@ -2046,6 +2063,11 @@ static void damos_set_quota_goal_current_value(struct damos_quota_goal *goal)
case DAMOS_QUOTA_NODE_MEM_FREE_BP:
goal->current_value = damos_get_node_mem_bp(goal);
break;
+ case DAMOS_QUOTA_ACTIVE_MEM_BP:
+ case DAMOS_QUOTA_INACTIVE_MEM_BP:
+ goal->current_value = damos_get_in_active_mem_bp(
+ goal->metric == DAMOS_QUOTA_ACTIVE_MEM_BP);
+ break;
default:
break;
}
--
2.39.5
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