linux-kernel - [RFC PATCH 3/6] mm/damon/core: check received access reports

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-Id: <20250629201443.52569-4-sj@kernel.org>
Date: Sun, 29 Jun 2025 13:14:40 -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 3/6] mm/damon/core: check received access reports

Reported access information is only saved in the core layer's internal
data structure.  Those are not really being used for final monitoring
results.  Update core layer access information (DAMON regions) using the
reported access information.

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

diff --git a/mm/damon/core.c b/mm/damon/core.c
index b54ed91f2dce..59567d79af99 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -2472,6 +2472,46 @@ static void kdamond_init_ctx(struct damon_ctx *ctx)
 	}
 }
 
+static void kdamond_apply_access_report(struct damon_access_report *report,
+		struct damon_target *t, struct damon_ctx *ctx)
+{
+	struct damon_region *r;
+
+	if (ctx->ops.eligible_report && !ctx->ops.eligible_report(report, t))
+		return;
+
+	/* todo: make search faster, e.g., binary search? */
+	damon_for_each_region(r, t) {
+		if (report->addr < r->ar.start)
+			continue;
+		if (r->ar.end < report->addr + report->size)
+			continue;
+		r->nr_accesses += report->nr_accesses;
+	}
+}
+
+static void kdamond_check_reported_accesses(struct damon_ctx *ctx)
+{
+	int i;
+	struct damon_access_report *report;
+	struct damon_target *t;
+
+	mutex_lock(&damon_access_reports_lock);
+	for (i = 0; i < damon_access_reports_len; i++) {
+		report = &damon_access_reports[i];
+		if (time_before(report->report_jiffies,
+					jiffies -
+					usecs_to_jiffies(
+						ctx->attrs.sample_interval)))
+			continue;
+		if (report->pid && !damon_target_has_pid(ctx))
+			continue;
+		damon_for_each_target(t, ctx)
+			kdamond_apply_access_report(report, t, ctx);
+	}
+	mutex_unlock(&damon_access_reports_lock);
+}
+
 /*
  * The monitoring daemon that runs as a kernel thread
  */
@@ -2518,6 +2558,7 @@ static int kdamond_fn(void *data)
 		kdamond_usleep(sample_interval);
 		ctx->passed_sample_intervals++;
 
+		kdamond_check_reported_accesses(ctx);
 		if (ctx->ops.check_accesses)
 			max_nr_accesses = ctx->ops.check_accesses(ctx);
 
-- 
2.39.5