From: Brendan Jackman <jackmanb@google.com>
Date: Tue, 26 May 2026 11:28:36 +0000 (+0000)
Subject: mm/page_alloc: remove VM_BUG_ON()s from pindex helpers
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=62f272d2fbffa7494e4d01c35a3a7b30d71b30a1;p=thirdparty%2Flinux.git

mm/page_alloc: remove VM_BUG_ON()s from pindex helpers

Vlastimil pointed out that the VM_BUG_ON()s have fallen out of favour, so
remove them.

Link: https://lore.kernel.org/20260526-page_alloc-unmapped-prep-v2-1-412f4d486115@google.com
Signed-off-by: Brendan Jackman <jackmanb@google.com>
Suggested-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Link: https://lore.kernel.org/all/4074a816-9e75-45a6-8141-25459bcc106b@kernel.org/
Reviewed-by: Vlastimil Babka (SUSE) <vbabka@kernel.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Suren Baghdasaryan <surenb@google.com>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7e3c79e79e5b..97cb95820592 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -653,13 +653,8 @@ static inline unsigned int order_to_pindex(int migratetype, int order)
 	if (IS_ENABLED(CONFIG_TRANSPARENT_HUGEPAGE)) {
 		bool movable = migratetype == MIGRATE_MOVABLE;
 
-		if (order > PAGE_ALLOC_COSTLY_ORDER) {
-			VM_BUG_ON(!is_pmd_order(order));
-
+		if (order > PAGE_ALLOC_COSTLY_ORDER)
 			return NR_LOWORDER_PCP_LISTS + movable;
-		}
-	} else {
-		VM_BUG_ON(order > PAGE_ALLOC_COSTLY_ORDER);
 	}
 
 	return (MIGRATE_PCPTYPES * order) + migratetype;
@@ -672,8 +667,6 @@ static inline int pindex_to_order(unsigned int pindex)
 	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;