mm/damon/stat: use damon_set_region_system_rams_default()

damon_stat_set_moniotirng_region() is nearly a duplicate of the core
function, damon_set_region_system_rams_default().  Use the core
implementation.

Link: https://lore.kernel.org/20260429041232.90257-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: David Hildenbrand <david@kernel.org>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Liam R. Howlett <liam@infradead.org>
Cc: Lorenzo Stoakes <ljs@kernel.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

1 files changed, 3 insertions, 50 deletions

diff --git a/mm/damon/stat.c b/mm/damon/stat.c
index 3951b762cbdd..f4d3203e9263 100644
--- a/mm/damon/stat.c
+++ b/mm/damon/stat.c
@@ -148,59 +148,12 @@ static int damon_stat_damon_call_fn(void *data)
 	return 0;
 }
 
-struct damon_stat_system_ram_range_walk_arg {
-	bool walked;
-	struct resource res;
-};
-
-static int damon_stat_system_ram_walk_fn(struct resource *res, void *arg)
-{
-	struct damon_stat_system_ram_range_walk_arg *a = arg;
-
-	if (!a->walked) {
-		a->walked = true;
-		a->res.start = res->start;
-	}
-	a->res.end = res->end;
-	return 0;
-}
-
-static unsigned long damon_stat_res_to_core_addr(resource_size_t ra,
-		unsigned long addr_unit)
-{
-	/*
-	 * Use div_u64() for avoiding linking errors related with __udivdi3,
-	 * __aeabi_uldivmod, or similar problems.  This should also improve the
-	 * performance optimization (read div_u64() comment for the detail).
-	 */
-	if (sizeof(ra) == 8 && sizeof(addr_unit) == 4)
-		return div_u64(ra, addr_unit);
-	return ra / addr_unit;
-}
-
-static int damon_stat_set_monitoring_region(struct damon_target *t,
-		unsigned long addr_unit, unsigned long min_region_sz)
-{
-	struct damon_addr_range addr_range;
-	struct damon_stat_system_ram_range_walk_arg arg = {};
-
-	walk_system_ram_res(0, -1, &arg, damon_stat_system_ram_walk_fn);
-	if (!arg.walked)
-		return -EINVAL;
-	addr_range.start = damon_stat_res_to_core_addr(
-			arg.res.start, addr_unit);
-	addr_range.end = damon_stat_res_to_core_addr(
-			arg.res.end + 1, addr_unit);
-	if (addr_range.end <= addr_range.start)
-		return -EINVAL;
-	return damon_set_regions(t, &addr_range, 1, min_region_sz);
-}
-
 static struct damon_ctx *damon_stat_build_ctx(void)
 {
 	struct damon_ctx *ctx;
 	struct damon_attrs attrs;
 	struct damon_target *target;
+	unsigned long start = 0, end = 0;
 
 	ctx = damon_new_ctx();
 	if (!ctx)
@@ -230,8 +183,8 @@ static struct damon_ctx *damon_stat_build_ctx(void)
 	if (!target)
 		goto free_out;
 	damon_add_target(ctx, target);
-	if (damon_stat_set_monitoring_region(target, ctx->addr_unit,
-				ctx->min_region_sz))
+	if (damon_set_region_system_rams_default(target, &start, &end,
+				ctx->addr_unit, ctx->min_region_sz))
 		goto free_out;
 	return ctx;
 free_out: