linux-kernel - [PATCH v3] mm/damon/core: remove unnecessary si

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Date:   Wed, 20 Sep 2023 09:57:27 +0800
From:   Huan Yang <link@...o.com>
To:     SeongJae Park <sj@...nel.org>,
        Andrew Morton <akpm@...ux-foundation.org>,
        damon@...ts.linux.dev, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org
Cc:     opensource.kernel@...o.com, Huan Yang <link@...o.com>
Subject: [PATCH v3] mm/damon/core: remove unnecessary si_meminfo invoke.

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@...o.com>
---
Change from v1:
v1 fold free mem rate logic into __damos_get_wmark_free_mem_rate and not
invoke si_meminfo, just get free/ram_pages in global.
v2 cancel this __damos_get_wmark_free_mem_rate and just calculate rate
in damos_wmark_metric_value to keep it simple.
v3 fix changelog format, fix code style.


 mm/damon/core.c | 6 ++----
 1 file changed, 2 insertions(+), 4 deletions(-)

diff --git a/mm/damon/core.c b/mm/damon/core.c
index bcd2bd9d6c10..6ceb52298904 100644
--- a/mm/damon/core.c
+++ b/mm/damon/core.c
@@ -1280,12 +1280,10 @@ static bool kdamond_need_stop(struct damon_ctx *ctx)
 
 static unsigned long damos_wmark_metric_value(enum damos_wmark_metric metric)
 {
-	struct sysinfo i;
-
 	switch (metric) {
 	case DAMOS_WMARK_FREE_MEM_RATE:
-		si_meminfo(&i);
-		return i.freeram * 1000 / i.totalram;
+		return global_zone_page_state(NR_FREE_PAGES) * 1000 /
+		       totalram_pages();
 	default:
 		break;
 	}
-- 
2.34.1