linux-kernel - [PATCH 10/21] mm/page_alloc: remove ifdefs from pindex helpers

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Message-ID: <20250924-b4-asi-page-alloc-v1-10-2d861768041f@google.com>
Date: Wed, 24 Sep 2025 14:59:45 +0000
From: Brendan Jackman <jackmanb@...gle.com>
To: jackmanb@...gle.com, Andy Lutomirski <luto@...nel.org>, 
	Lorenzo Stoakes <lorenzo.stoakes@...cle.com>, "Liam R. Howlett" <Liam.Howlett@...cle.com>, 
	Suren Baghdasaryan <surenb@...gle.com>, Michal Hocko <mhocko@...e.com>, 
	Johannes Weiner <hannes@...xchg.org>, Zi Yan <ziy@...dia.com>, 
	Axel Rasmussen <axelrasmussen@...gle.com>, Yuanchu Xie <yuanchu@...gle.com>, 
	Roman Gushchin <roman.gushchin@...ux.dev>
Cc: peterz@...radead.org, bp@...en8.de, dave.hansen@...ux.intel.com, 
	mingo@...hat.com, tglx@...utronix.de, akpm@...ux-foundation.org, 
	david@...hat.com, derkling@...gle.com, junaids@...gle.com, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, reijiw@...gle.com, 
	rientjes@...gle.com, rppt@...nel.org, vbabka@...e.cz, x86@...nel.org, 
	yosry.ahmed@...ux.dev
Subject: [PATCH 10/21] mm/page_alloc: remove ifdefs from pindex helpers

The ifdefs are not technically needed here, everything used here is
always defined.

They aren't doing much harm right now but a following patch will
complicate these functions. Switching to IS_ENABLED() makes the code a
bit less tiresome to read.

Signed-off-by: Brendan Jackman <jackmanb@...gle.com>
---
 mm/page_alloc.c | 30 ++++++++++++++----------------
 1 file changed, 14 insertions(+), 16 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 10757410da2127b0488c99c5933422fc649f9a1d..08e0faab992fcf3c426d4783da041f930075d903 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -656,19 +656,17 @@ static void bad_page(struct page *page, const char *reason)
 
 static inline unsigned int order_to_pindex(int migratetype, int order)
 {
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
+		bool movable = migratetype == MIGRATE_MOVABLE;
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	bool movable;
-	if (order > PAGE_ALLOC_COSTLY_ORDER) {
-		VM_BUG_ON(order != HPAGE_PMD_ORDER);
+		if (order > PAGE_ALLOC_COSTLY_ORDER) {
+			VM_BUG_ON(order != HPAGE_PMD_ORDER);
 
-		movable = migratetype == MIGRATE_MOVABLE;
-
-		return NR_LOWORDER_PCP_LISTS + movable;
+			return NR_LOWORDER_PCP_LISTS + movable;
+		}
+	} else {
+		VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
 	}
-#else
-	VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
-#endif
 
 	return (MIGRATE_PCPTYPES * order) + migratetype;
 }
@@ -677,12 +675,12 @@ static inline int pindex_to_order(unsigned int pindex)
 {
 	int order = pindex / MIGRATE_PCPTYPES;
 
-#ifdef CONFIG_TRANSPARENT_HUGEPAGE
-	if (pindex >= NR_LOWORDER_PCP_LISTS)
-		order = HPAGE_PMD_ORDER;
-#else
-	VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
-#endif
+	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
+		if (pindex >= NR_LOWORDER_PCP_LISTS)
+			order = HPAGE_PMD_ORDER;
+	} else {
+		VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
+	}
 
 	return order;
 }

-- 
2.50.1