1 files changed, 72 insertions, 5 deletions
diff --git a/mm/damon/core.c b/mm/damon/core.c
index 05e4bef367dbf..980a31cd3498e 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -3328,14 +3328,20 @@ done:
 	return 0;
 }
 
-static int walk_system_ram(struct resource *res, void *arg)
+struct damon_system_ram_range_walk_arg {
+	bool walked;
+	struct resource res;
+};
+
+static int damon_system_ram_walk_fn(struct resource *res, void *arg)
 {
-	struct resource *a = arg;
+	struct damon_system_ram_range_walk_arg *a = arg;
 
-	if (resource_size(a) < resource_size(res)) {
-		a->start = res->start;
-		a->end = res->end;
+	if (!a->walked) {
+		a->walked = true;
+		a->res.start = res->start;
 	}
+	a->res.end = res->end;
 	return 0;
 }
 
@@ -3352,6 +3358,67 @@ static unsigned long damon_res_to_core_addr(resource_size_t ra,
 	return ra / addr_unit;
 }
 
+static bool damon_find_system_rams_range(unsigned long *start,
+		unsigned long *end, unsigned long addr_unit)
+{
+	struct damon_system_ram_range_walk_arg arg = {};
+
+	walk_system_ram_res(0, -1, &arg, damon_system_ram_walk_fn);
+	if (!arg.walked)
+		return false;
+	*start = damon_res_to_core_addr(arg.res.start, addr_unit);
+	*end = damon_res_to_core_addr(arg.res.end + 1, addr_unit);
+	if (*end <= *start)
+		return false;
+	return true;
+}
+
+/**
+ * damon_set_region_system_rams_default() - Set the region of the given
+ * monitoring target as requested, or to cover all 'System RAM' resources.
+ * @t:		The monitoring target to set the region.
+ * @start:	The pointer to the start address of the region.
+ * @end:	The pointer to the end address of the region.
+ * @addr_unit:	The address unit for the damon_ctx of @t.
+ * @min_region_sz:	Minimum region size.
+ *
+ * This function sets the region of @t as requested by @start and @end.  If the
+ * values of @start and @end are zero, however, this function finds 'System
+ * RAM' resources and sets the region to cover all the resource.  In the latter
+ * case, this function saves the start and the end addresseses of the first and
+ * the last resources in @start and @end, respectively.
+ *
+ * Return: 0 on success, negative error code otherwise.
+ */
+int damon_set_region_system_rams_default(struct damon_target *t,
+			unsigned long *start, unsigned long *end,
+			unsigned long addr_unit, unsigned long min_region_sz)
+{
+	struct damon_addr_range addr_range;
+
+	if (*start > *end)
+		return -EINVAL;
+
+	if (!*start && !*end &&
+		!damon_find_system_rams_range(start, end, addr_unit))
+		return -EINVAL;
+
+	addr_range.start = *start;
+	addr_range.end = *end;
+	return damon_set_regions(t, &addr_range, 1, min_region_sz);
+}
+
+static int walk_system_ram(struct resource *res, void *arg)
+{
+	struct resource *a = arg;
+
+	if (resource_size(a) < resource_size(res)) {
+		a->start = res->start;
+		a->end = res->end;
+	}
+	return 0;
+}
+
 /*
  * Find biggest 'System RAM' resource and store its start and end address in
  * @start and @end, respectively.  If no System RAM is found, returns false.