From 04cf7ec7ed9f44ddf2b674e8ebbe0087e87708f3 Mon Sep 17 00:00:00 2001
From: Ye Liu <liuye@kylinos.cn>
Date: Thu, 14 Aug 2025 17:00:52 +0800
Subject: [PATCH] mm/page_alloc: simplify lowmem_reserve max calculation

Use max() to find the maximum lowmem_reserve value and min_t() to cap it
to managed_pages in calculate_totalreserve_pages(), instead of open-coding
the comparisons.  No functional change.

Link: https://lkml.kernel.org/r/20250814090053.22241-1-ye.liu@linux.dev
Signed-off-by: Ye Liu <liuye@kylinos.cn>
Acked-by: Johannes Weiner <hannes@cmpxchg.org>
Acked-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Wei Yang <richard.weiyang@gmail.com>
Cc: Brendan Jackman <jackmanb@google.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
 mm/page_alloc.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 09241bb7663e..35b2bf61b78d 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -6237,8 +6237,7 @@ static void calculate_totalreserve_pages(void)
 
 			/* Find valid and maximum lowmem_reserve in the zone */
 			for (j = i; j < MAX_NR_ZONES; j++) {
-				if (zone->lowmem_reserve[j] > max)
-					max = zone->lowmem_reserve[j];
+				max = max(max, zone->lowmem_reserve[j]);
 			}
 
 			/* we treat the high watermark as reserved pages. */
-- 
2.51.0