+ mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.patch added to mm-unstable branch

[Andrew Morton <akpm@linux-foundation.org>]

The patch titled
     Subject: mm/vmalloc: align vm_area so vmap() can batch mappings
has been added to the -mm mm-unstable branch.  Its filename is
     mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.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: "Barry Song (Xiaomi)" <baohua@kernel.org>
Subject: mm/vmalloc: align vm_area so vmap() can batch mappings
Date: Wed, 15 Jul 2026 20:08:13 +0800

Try to align the vmap virtual address to PMD_SHIFT or a larger PTE mapping
size hinted by the architecture, so contiguous pages can be batch-mapped
when setting PMD or PTE entries.  We do not expect any significant
overhead for this.

Add __get_vm_area_node_aligned_caller() as a wrapper over
__get_vm_area_node() to simplify repeated calls with fixed arguments.

Link: https://lore.kernel.org/20260715120813.3609949-8-jiangwen6@xiaomi.com
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Tested-by: Xueyuan Chen <xueyuan.chen21@gmail.com>
Tested-by: Leo Yan <leo.yan@arm.com>
Reviewed-by: Uladzislau Rezki (Sony) <urezki@gmail.com>
Reviewed-by: Dev Jain <dev.jain@arm.com>
Cc: Andrew Donnellan <ajd@linux.ibm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Wen Jiang <jiangwenxiaomi@gmail.com>
Cc: Will Deacon <will@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 mm/vmalloc.c |   35 ++++++++++++++++++++++++++++++++++-
 1 file changed, 34 insertions(+), 1 deletion(-)

--- a/mm/vmalloc.c~mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings
+++ a/mm/vmalloc.c
@@ -3338,6 +3338,14 @@ struct vm_struct *get_vm_area_caller(uns
 				  NUMA_NO_NODE, GFP_KERNEL, caller);
 }
 
+static struct vm_struct *__get_vm_area_node_aligned_caller(unsigned long size,
+		unsigned long align, unsigned long flags, const void *caller)
+{
+	return __get_vm_area_node(size, align, PAGE_SHIFT, flags,
+				  VMALLOC_START, VMALLOC_END,
+				  NUMA_NO_NODE, GFP_KERNEL, caller);
+}
+
 /**
  * find_vm_area - find a continuous kernel virtual area
  * @addr:	  base address
@@ -3664,6 +3672,30 @@ out:
 	return err;
 }
 
+static struct vm_struct *vmap_get_aligned_vm_area(unsigned long size,
+		unsigned long flags, pgprot_t prot, const void *caller)
+{
+	struct vm_struct *vm_area;
+	unsigned int shift;
+
+	if (arch_vmap_pmd_supported(prot) && size >= PMD_SIZE) {
+		vm_area = __get_vm_area_node_aligned_caller(size, PMD_SIZE,
+				flags, caller);
+		if (vm_area)
+			return vm_area;
+	}
+
+	shift = arch_vmap_pte_supported_shift(size);
+	if (shift > PAGE_SHIFT) {
+		vm_area = __get_vm_area_node_aligned_caller(size, 1UL << shift,
+				flags, caller);
+		if (vm_area)
+			return vm_area;
+	}
+
+	return __get_vm_area_node_aligned_caller(size, PAGE_SIZE, flags, caller);
+}
+
 /**
  * vmap - map an array of pages into virtually contiguous space
  * @pages: array of page pointers
@@ -3702,7 +3734,8 @@ void *vmap(struct page **pages, unsigned
 		return NULL;
 
 	size = (unsigned long)count << PAGE_SHIFT;
-	area = get_vm_area_caller(size, flags, __builtin_return_address(0));
+	area = vmap_get_aligned_vm_area(size, flags, prot,
+				__builtin_return_address(0));
 	if (!area)
 		return NULL;
 
_

Patches currently in -mm which might be from baohua@kernel.org are

mm-avoid-unnecessary-lru-drain-for-wp_can_reuse_anon_folio.patch
mm-avoid-unnecessary-lru-drain-for-wp_can_reuse_anon_folio-fix.patch
mm-drop-stale-folio_ref_count==1-check-in-do_swap_page-reuse-logic.patch
mm-entirely-remove-lru_add_drain-in-do_swap_page.patch
mm-clarify-the-folio_free_swap-for-do_swap_page.patch
arm64-hugetlb-extend-batching-of-multiple-cont_pte-in-a-single-pte-setup.patch
arm64-vmalloc-allow-arch_vmap_pte_range_map_size-to-batch-multiple-cont_pte.patch
mm-vmalloc-extend-page-table-walk-to-support-larger-page_shift-sizes-and-eliminate-page-table-rewalk.patch
mm-vmalloc-map-contiguous-pages-in-batches-for-vmap-if-possible.patch
mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.patch