linux-kernel - [PATCH] mm/percpu: drop unused max_upa in pcpu_build_alloc

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Message-Id: <20251208092627.5603-1-niuwl1@chinatelecom.cn>
Date: Mon,  8 Dec 2025 17:26:27 +0800
From: WanLi Niu <niuwl1@...natelecom.cn>
To: Dennis Zhou <dennis@...nel.org>
Cc: Tejun Heo <tj@...nel.org>,
	Christoph Lameter <cl@...two.org>,
	Andrew Morton <akpm@...ux-foundation.org>,
	WanLi Niu <niuwl1@...natelecom.cn>,
	hlleng <a909204013@...il.com>,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org
Subject: [PATCH] mm/percpu: drop unused max_upa in pcpu_build_alloc_info()

pcpu_build_alloc_info() only needs the initial upa as the starting point
for the downward search. Storing it in max_upa and reusing it adds
no value. Iterate from upa directly to remove the redundant local variable
without changing behavior, improving readability.

Signed-off-by: WanLi Niu <niuwl1@...natelecom.cn>
Co-developed-by: hlleng <a909204013@...il.com>
Signed-off-by: hlleng <a909204013@...il.com>
---
 mm/percpu.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/mm/percpu.c b/mm/percpu.c
index 81462ce58..966f4405f 100644
--- a/mm/percpu.c
+++ b/mm/percpu.c
@@ -2800,7 +2800,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
 	const size_t static_size = __per_cpu_end - __per_cpu_start;
 	int nr_groups = 1, nr_units = 0;
 	size_t size_sum, min_unit_size, alloc_size;
-	int upa, max_upa, best_upa;	/* units_per_alloc */
+	int upa, best_upa;	/* units_per_alloc */
 	int last_allocs, group, unit;
 	unsigned int cpu, tcpu;
 	struct pcpu_alloc_info *ai;
@@ -2817,7 +2817,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
 	dyn_size = size_sum - static_size - reserved_size;
 
 	/*
-	 * Determine min_unit_size, alloc_size and max_upa such that
+	 * Determine min_unit_size, alloc_size such that
 	 * alloc_size is multiple of atom_size and is the smallest
 	 * which can accommodate 4k aligned segments which are equal to
 	 * or larger than min_unit_size.
@@ -2829,7 +2829,6 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
 	upa = alloc_size / min_unit_size;
 	while (alloc_size % upa || (offset_in_page(alloc_size / upa)))
 		upa--;
-	max_upa = upa;
 
 	cpumask_copy(&mask, cpu_possible_mask);
 
@@ -2860,7 +2859,7 @@ static struct pcpu_alloc_info * __init __flatten pcpu_build_alloc_info(
 	 */
 	last_allocs = INT_MAX;
 	best_upa = 0;
-	for (upa = max_upa; upa; upa--) {
+	for (; upa; upa--) {
 		int allocs = 0, wasted = 0;
 
 		if (alloc_size % upa || (offset_in_page(alloc_size / upa)))
-- 
2.39.1