+ mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back.patch added to mm-unstable branch

+ mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back.patch added to mm-unstable branch

[Andrew Morton]

The patch titled
     Subject: mm: hugetlb_vmemmap: add check of CONFIG_MEMORY_HOTPLUG back
has been added to the -mm mm-unstable branch.  Its filename is
     mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back.patch

This patch will later appear in the mm-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: Muchun Song <songmuchun@bytedance.com>
Subject: mm: hugetlb_vmemmap: add check of CONFIG_MEMORY_HOTPLUG back
Date: Tue, 5 Dec 2023 11:05:30 +0800

The compiler will optimize the code as much as possible if we add the
check of CONFIG_MEMORY_HOTPLUG back.

Link: https://lkml.kernel.org/r/20231205030530.3802-1-songmuchun@bytedance.com
Signed-off-by: Muchun Song <songmuchun@bytedance.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/hugetlb_vmemmap.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/mm/hugetlb_vmemmap.c~mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back
+++ a/mm/hugetlb_vmemmap.c
@@ -119,7 +119,7 @@ static int vmemmap_pmd_entry(pmd_t *pmd,
 	 *   +--+ |                        |
 	 *        +------------------------+
 	 */
-	if (unlikely(!vmemmap_walk->nr_walked)) {
+	if (IS_ENABLED(CONFIG_MEMORY_HOTPLUG) && unlikely(!vmemmap_walk->nr_walked)) {
 		struct page *page = head ? head + pte_index(addr) :
 				    pte_page(ptep_get(pte_offset_kernel(pmd, addr)));
 
_

Patches currently in -mm which might be from songmuchun@bytedance.com are

mm-pagewalk-assert-write-mmap-lock-only-for-walking-the-user-page-tables.patch
mm-hugetlb_vmemmap-use-walk_page_range_novma-to-simplify-the-code.patch
mm-hugetlb_vmemmap-move-pagevmemmapselfhosted-check-to-split_vmemmap_huge_pmd.patch
mm-hugetlb_vmemmap-convert-page-to-folio.patch
mm-hugetlb_vmemmap-add-check-of-config_memory_hotplug-back.patch
mm-hugetlb_vmemmap-move-mmap-lock-to-vmemmap_remap_range.patch