[RFC PATCH v3 18/37] mm/damon/core: apply sample filter to access reports

SeongJae Park
2025-12-08T06:30:16Z

The data structure for access sample results filtering is not really
being used on the core layer. Implement the support.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/damon/core.c | 41 +++++++++++++++++++++++++++++++++++++++++
1 file changed, 41 insertions(+)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index d952a833a05e..b627fc84161c 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -586,6 +586,13 @@ static struct damon_sample_filter *damon_nth_sample_filter(int n,
return NULL;
}

+static struct damon_sample_filter *damon_last_sample_filter_or_null(
+ struct damon_sample_control *ctrl)
+{
+ return list_last_entry_or_null(&ctrl->sample_filters,
+ struct damon_sample_filter, list);
+}
+
struct damon_ctx *damon_new_ctx(void)
{
struct damon_ctx *ctx;
@@ -2866,11 +2873,45 @@ static void kdamond_init_ctx(struct damon_ctx *ctx)
}
}

+static bool damon_sample_filter_matching(struct damon_access_report *report,
+ struct damon_sample_filter *filter)
+{
+ bool matched = false;
+
+ switch (filter->type) {
+ case DAMON_FILTER_TYPE_CPUMASK:
+ matched = cpumask_test_cpu(report->cpu, &filter->cpumask);
+ break;
+ default:
+ break;
+ }
+ return matched == filter->matching;
+}
+
+static bool damon_sample_filter_out(struct damon_access_report *report,
+ struct damon_sample_control *ctrl)
+{
+ struct damon_sample_filter *filter;
+
+ damon_for_each_sample_filter(filter, ctrl) {
+ if (damon_sample_filter_matching(report, filter) &&
+ !filter->allow)
+ return true;
+ }
+ filter = damon_last_sample_filter_or_null(ctrl);
+ if (!filter)
+ return false;
+ return !filter->allow;
+}
+
static void kdamond_apply_access_report(struct damon_access_report *report,
struct damon_target *t, struct damon_ctx *ctx)
{
struct damon_region *r;

+ if (damon_sample_filter_out(report, &ctx->sample_control))
+ return;
+
/* todo: make search faster, e.g., binary search? */
damon_for_each_region(r, t) {
if (report->addr < r->ar.start)
--
2.47.3