From: Wei Yang <richard.weiyang@gmail.com>
Date: Fri, 10 Oct 2025 14:11:42 +0000 (+0000)
Subject: mm/huge_memory: only get folio_order() once during __folio_split()
X-Git-Url: https://www.infradead.org/git/?a=commitdiff_plain;h=94df3485260f14fd629f7c59a805597ee788bb42;p=users%2Fjedix%2Flinux-maple.git

mm/huge_memory: only get folio_order() once during __folio_split()

Before splitting folio, its order keeps the same.

It is only necessary to get folio_order() once.

Also rename order to old_order to represent the original folio order.

Link: https://lkml.kernel.org/r/20251010141142.1349-1-richard.weiyang@gmail.com
Signed-off-by: Wei Yang <richard.weiyang@gmail.com>
Acked-by: Lance Yang <lance.yang@linux.dev>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Zi Yan <ziy@nvidia.com>
Cc: Dev Jain <dev.jain@arm.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: "Liam R. Howlett" <Liam.Howlett@oracle.com>
Cc: Nico Pache <npache@redhat.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Barry Song <baohua@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 068e20711c43..f212b4a6d8fc 100644
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -3701,7 +3701,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
 	bool is_anon = folio_test_anon(folio);
 	struct address_space *mapping = NULL;
 	struct anon_vma *anon_vma = NULL;
-	int order = folio_order(folio);
+	int old_order = folio_order(folio);
 	struct folio *new_folio, *next;
 	int nr_shmem_dropped = 0;
 	int remap_flags = 0;
@@ -3715,7 +3715,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
 	if (folio != page_folio(split_at) || folio != page_folio(lock_at))
 		return -EINVAL;
 
-	if (new_order >= folio_order(folio))
+	if (new_order >= old_order)
 		return -EINVAL;
 
 	if (uniform_split && !uniform_split_supported(folio, new_order, true))
@@ -3787,7 +3787,7 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
 
 		if (uniform_split) {
 			xas_set_order(&xas, folio->index, new_order);
-			xas_split_alloc(&xas, folio, folio_order(folio), gfp);
+			xas_split_alloc(&xas, folio, old_order, gfp);
 			if (xas_error(&xas)) {
 				ret = xas_error(&xas);
 				goto out;
@@ -3843,13 +3843,13 @@ static int __folio_split(struct folio *folio, unsigned int new_order,
 		struct lruvec *lruvec;
 		int expected_refs;
 
-		if (folio_order(folio) > 1 &&
+		if (old_order > 1 &&
 		    !list_empty(&folio->_deferred_list)) {
 			ds_queue->split_queue_len--;
 			if (folio_test_partially_mapped(folio)) {
 				folio_clear_partially_mapped(folio);
-				mod_mthp_stat(folio_order(folio),
-					      MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1);
+				mod_mthp_stat(old_order,
+					MTHP_STAT_NR_ANON_PARTIALLY_MAPPED, -1);
 			}
 			/*
 			 * Reinitialize page_deferred_list after removing the
@@ -3977,7 +3977,7 @@ fail:
 	if (!ret && is_anon && !folio_is_device_private(folio))
 		remap_flags = RMP_USE_SHARED_ZEROPAGE;
 
-	remap_page(folio, 1 << order, remap_flags);
+	remap_page(folio, 1 << old_order, remap_flags);
 
 	/*
 	 * Unlock all after-split folios except the one containing
@@ -4008,9 +4008,9 @@ out_unlock:
 		i_mmap_unlock_read(mapping);
 out:
 	xas_destroy(&xas);
-	if (order == HPAGE_PMD_ORDER)
+	if (old_order == HPAGE_PMD_ORDER)
 		count_vm_event(!ret ? THP_SPLIT_PAGE : THP_SPLIT_PAGE_FAILED);
-	count_mthp_stat(order, !ret ? MTHP_STAT_SPLIT : MTHP_STAT_SPLIT_FAILED);
+	count_mthp_stat(old_order, !ret ? MTHP_STAT_SPLIT : MTHP_STAT_SPLIT_FAILED);
 	return ret;
 }