+ mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings.patch added to mm-new 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-new 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-new branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

Note, mm-new is a provisional staging ground for work-in-progress
patches, and acceptance into mm-new is a notification for others take
notice and to finish up reviews.  Please do not hesitate to respond to
review feedback and post updated versions to replace or incrementally
fixup patches in mm-new.

The mm-new branch of mm.git is not included in linux-next

If a few days of testing in mm-new is successful, the patch will me moved
into mm.git's mm-unstable branch, which is included in linux-next

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------------------------------------------------------
From: "Barry Song (Xiaomi)" <baohua@kernel.org>
Subject: mm/vmalloc: align vm_area so vmap() can batch mappings
Date: Sat, 07 Nov 2026 21:49:53 +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/20261107134953.748622-11-jiangwenxiaomi@gmail.com
Signed-off-by: Barry Song (Xiaomi) <baohua@kernel.org>
Signed-off-by: Wen Jiang <jiangwen6@xiaomi.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
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: Catalin Marinas <catalin.marinas@arm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Anshuman Khandual <anshuman.khandual@arm.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: Mike Rapoport <rppt@kernel.org>
Cc: Christophe Leroy <chleroy@kernel.org>
Cc: Madhavan Srinivasan <maddy@linux.ibm.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Andrew Donnellan <andrew+kernel@donnellan.id.au>
Cc: Wen Jiang <jiangwenxiaomi@gmail.com>
---

 mm/vmalloc.c |   36 ++++++++++++++++++++++++++++++++++--
 1 file changed, 34 insertions(+), 2 deletions(-)

--- a/mm/vmalloc.c~mm-vmalloc-align-vm_area-so-vmap-can-batch-mappings
+++ a/mm/vmalloc.c
@@ -3378,6 +3378,14 @@ 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
@@ -3709,6 +3717,30 @@ 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
@@ -3747,8 +3779,8 @@ void *vmap(struct page **pages, unsigned
 		return NULL;
 
 	size = (unsigned long)count << PAGE_SHIFT;
-	area = get_vm_area_caller(size, flags | VM_UNINITIALIZED,
-				  __builtin_return_address(0));
+	area = vmap_get_aligned_vm_area(size, flags | VM_UNINITIALIZED, prot,
+					__builtin_return_address(0));
 	if (!area)
 		return NULL;
 
_

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

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