[PATCH] mm/damon/core: remove unnecessary si_meminfo invoke.

[Huan Yang <link@vivo.com>]

si_meminfo() will read and assign more info not just free/ram pages.
For just DAMOS_WMARK_FREE_MEM_RATE use, only get free and ram pages
is ok to save cpu.

Signed-off-by: Huan Yang <link@vivo.com>
---
 mm/damon/core.c | 10 ++++++----
 1 file changed, 6 insertions(+), 4 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index bcd2bd9d6c10..1cddee9ae73b 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1278,14 +1278,16 @@ static bool kdamond_need_stop(struct damon_ctx *ctx)
 	return true;
 }
 
-static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric)
+static unsigned long __damons_get_wmark_free_mem_rate(void)
 {
-	struct sysinfo i;
+	return global_zone_page_state(NR_FREE_PAGES) * 1000 / totalram_pages();
+}
 
+static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric)
+{
 	switch (metric) {
 	case DAMOS_WMARK_FREE_MEM_RATE:
-		si_meminfo(&i);
-		return i.freeram * 1000 / i.totalram;
+		return __damons_get_wmark_free_mem_rate();
 	default:
 		break;
 	}
-- 
2.34.1