1 files changed, 47 insertions, 2 deletions

diff --git a/mm/damon/reclaim.c b/mm/damon/reclaim.c
index fb7c982a0018..7ba3d0f9a19a 100644
--- a/mm/damon/reclaim.c
+++ b/mm/damon/reclaim.c
@@ -129,6 +129,13 @@ static unsigned long monitor_region_end __read_mostly;
 module_param(monitor_region_end, ulong, 0600);
 
 /*
+ * Scale factor for DAMON_RECLAIM to ops address conversion.
+ *
+ * This parameter must not be set to 0.
+ */
+static unsigned long addr_unit __read_mostly = 1;
+
+/*
  * Skip anonymous pages reclamation.
  *
  * If this parameter is set as ``Y``, DAMON_RECLAIM does not reclaim anonymous
@@ -194,6 +201,15 @@ static int damon_reclaim_apply_parameters(void)
 	if (err)
 		return err;
 
+	/*
+	 * If monitor_region_start/end are unset, always silently
+	 * reset addr_unit to 1.
+	 */
+	if (!monitor_region_start && !monitor_region_end)
+		addr_unit = 1;
+	param_ctx->addr_unit = addr_unit;
+	param_ctx->min_sz_region = max(DAMON_MIN_REGION / addr_unit, 1);
+
 	if (!damon_reclaim_mon_attrs.aggr_interval) {
 		err = -EINVAL;
 		goto out;
@@ -294,6 +310,30 @@ static int damon_reclaim_turn(bool on)
 	return damon_call(ctx, &call_control);
 }
 
+static int damon_reclaim_addr_unit_store(const char *val,
+		const struct kernel_param *kp)
+{
+	unsigned long input_addr_unit;
+	int err = kstrtoul(val, 0, &input_addr_unit);
+
+	if (err)
+		return err;
+	if (!input_addr_unit)
+		return -EINVAL;
+
+	addr_unit = input_addr_unit;
+	return 0;
+}
+
+static const struct kernel_param_ops addr_unit_param_ops = {
+	.set = damon_reclaim_addr_unit_store,
+	.get = param_get_ulong,
+};
+
+module_param_cb(addr_unit, &addr_unit_param_ops, &addr_unit, 0600);
+MODULE_PARM_DESC(addr_unit,
+	"Scale factor for DAMON_RECLAIM to ops address conversion (default: 1)");
+
 static int damon_reclaim_enabled_store(const char *val,
 		const struct kernel_param *kp)
 {
@@ -309,7 +349,7 @@ static int damon_reclaim_enabled_store(const char *val,
 		return 0;
 
 	/* Called before init function.  The function will handle this. */
-	if (!ctx)
+	if (!damon_initialized())
 		goto set_param_out;
 
 	err = damon_reclaim_turn(enable);
@@ -332,8 +372,13 @@ MODULE_PARM_DESC(enabled,
 
 static int __init damon_reclaim_init(void)
 {
-	int err = damon_modules_new_paddr_ctx_target(&ctx, &target);
+	int err;
 
+	if (!damon_initialized()) {
+		err = -ENOMEM;
+		goto out;
+	}
+	err = damon_modules_new_paddr_ctx_target(&ctx, &target);
 	if (err)
 		goto out;