mm/damon/lru_sort: respect addr_unit on default monitoring region setup

In the past, damon_set_region_biggest_system_ram_default(), which is the
core function for setting the default monitoring target region of
DAMON_LRU_SORT, didn't support addr_unit.  Hence DAMON_LRU_SORT was
silently ignoring the user input for addr_unit when the user doesn't
explicitly set the monitoring target regions, and therefore the default
target region is being used.  No real problem from that ignorance was
reported so far.  But, the implicit rule is only making things confusing.
Also, the default target region setup function is updated to support
addr_unit.  Hence there is no reason to keep ignoring it.  Respect the
user-passed addr_unit for the default target monitoring region use case.

Link: https://lkml.kernel.org/r/20260311052927.93921-6-sj@kernel.org
Signed-off-by: SeongJae Park <sj@kernel.org>
Cc: Yang yingliang <yangyingliang@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/mm/damon/lru_sort.c b/mm/damon/lru_sort.c
index 133ea17e258df3c9249397164607f8b5728b8b56..554559d729760080db97913b97dc9b1ba6a766cb 100644 (file)
--- a/mm/damon/lru_sort.c
+++ b/mm/damon/lru_sort.c
@@ -291,12 +291,6 @@ static int damon_lru_sort_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_region_sz = max(DAMON_MIN_REGION_SZ / addr_unit, 1);