From: Dev Jain <dev.jain@arm•com>
To: Wen Jiang <jiangwenxiaomi@gmail•com>,
linux-mm@kvack•org, linux-arm-kernel@lists•infradead.org,
catalin.marinas@arm•com, will@kernel•org,
akpm@linux-foundation•org, urezki@gmail•com
Cc: baohua@kernel•org, Xueyuan.chen21@gmail•com, rppt@kernel•org,
david@kernel•org, ryan.roberts@arm•com,
anshuman.khandual@arm•com, ajd@linux•ibm.com,
linux-kernel@vger•kernel.org, jiangwen6@xiaomi•com
Subject: Re: [PATCH v3 6/6] mm/vmalloc: align vm_area so vmap() can batch mappings
Date: Wed, 27 May 2026 11:55:17 +0530 [thread overview]
Message-ID: <3f55655c-b50b-45fa-9314-23e35d04ae7e@arm.com> (raw)
In-Reply-To: <20260522053146.83209-7-jiangwenxiaomi@gmail.com>
On 22/05/26 11:01 am, Wen Jiang wrote:
> From: "Barry Song (Xiaomi)" <baohua@kernel•org>
>
> 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.
>
> 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>
Hmm okay I would have preferred to squash this in the previous, but
the correctness of previous patch does not rely on this, so it's fine.
> ---
> mm/vmalloc.c | 33 ++++++++++++++++++++++++++++++++-
> 1 file changed, 32 insertions(+), 1 deletion(-)
>
> diff --git a/mm/vmalloc.c b/mm/vmalloc.c
> index 50642246f4d40..040d400928aab 100644
> --- a/mm/vmalloc.c
> +++ b/mm/vmalloc.c
> @@ -3620,6 +3620,37 @@ static int vmap_batched(unsigned long addr, unsigned long end,
> return err;
> }
>
This is screaming for a helper :)
> +static struct vm_struct *get_aligned_vm_area(unsigned long size,
> + unsigned long flags, const void *caller)
Call this vmap_get_aligned_vm_area, then ...
> +{
> + struct vm_struct *vm_area;
> + unsigned int shift;
> +
> + /* Try PMD alignment for large sizes */
> + if (size >= PMD_SIZE) {
> + vm_area = __get_vm_area_node(size, PMD_SIZE, PAGE_SHIFT, flags,
> + VMALLOC_START, VMALLOC_END,
> + NUMA_NO_NODE, GFP_KERNEL, caller);
Add a wrapper over this called __get_vm_area_node_aligned_caller, which can
call __get_vm_area_node() with all other arguments fixed, except "align".
> + if (vm_area)
> + return vm_area;
> + }
> +
> + /* Try CONT_PTE alignment */
> + shift = arch_vmap_pte_supported_shift(size);
> + if (shift > PAGE_SHIFT) {
> + vm_area = __get_vm_area_node(size, 1UL << shift, PAGE_SHIFT, flags,
> + VMALLOC_START, VMALLOC_END,
> + NUMA_NO_NODE, GFP_KERNEL, caller);
> + if (vm_area)
> + return vm_area;
> + }
> +
> + /* Fall back to page alignment */
> + return __get_vm_area_node(size, PAGE_SIZE, PAGE_SHIFT, flags,
> + VMALLOC_START, VMALLOC_END,
> + NUMA_NO_NODE, GFP_KERNEL, caller);
> +}
> +
> /**
> * vmap - map an array of pages into virtually contiguous space
> * @pages: array of page pointers
> @@ -3658,7 +3689,7 @@ void *vmap(struct page **pages, unsigned int count,
> return NULL;
>
> size = (unsigned long)count << PAGE_SHIFT;
> - area = get_vm_area_caller(size, flags, __builtin_return_address(0));
> + area = get_aligned_vm_area(size, flags, __builtin_return_address(0));
> if (!area)
> return NULL;
>
next prev parent reply other threads:[~2026-05-27 6:25 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2026-05-22 5:31 [PATCH v3 0/6] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Wen Jiang
2026-05-22 5:31 ` [PATCH v3 1/6] arm64/hugetlb: Extend batching of multiple CONT_PTE in a single PTE setup Wen Jiang
2026-05-26 7:56 ` Dev Jain
2026-05-22 5:31 ` [PATCH v3 2/6] arm64/vmalloc: Allow arch_vmap_pte_range_map_size to batch multiple CONT_PTE Wen Jiang
2026-05-27 5:43 ` Dev Jain
2026-05-22 5:31 ` [PATCH v3 3/6] mm/vmalloc: Extract vmap_set_ptes() to consolidate PTE mapping logic Wen Jiang
2026-06-01 17:34 ` Uladzislau Rezki
2026-06-02 7:45 ` Wen Jiang
2026-05-22 5:31 ` [PATCH v3 4/6] mm/vmalloc: Extend page table walk to support larger page_shift sizes and eliminate page table rewalk Wen Jiang
2026-05-27 5:58 ` Dev Jain
2026-05-28 3:39 ` Wen Jiang
2026-05-29 5:28 ` Dev Jain
2026-06-05 6:02 ` Dev Jain
2026-05-22 5:31 ` [PATCH v3 5/6] mm/vmalloc: map contiguous pages in batches for vmap() if possible Wen Jiang
2026-05-27 8:27 ` Dev Jain
2026-05-28 3:42 ` Wen Jiang
2026-05-29 5:57 ` Dev Jain
2026-06-02 7:34 ` Wen Jiang
2026-05-22 5:31 ` [PATCH v3 6/6] mm/vmalloc: align vm_area so vmap() can batch mappings Wen Jiang
2026-05-23 7:53 ` Uladzislau Rezki
2026-05-27 6:25 ` Dev Jain [this message]
2026-06-02 8:57 ` Wen Jiang
2026-05-22 18:07 ` [PATCH v3 0/6] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory Andrew Morton
2026-05-23 8:26 ` Wen Jiang
2026-05-23 21:40 ` Andrew Morton
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