[PATCH v5 0/6] mm/vmalloc: Speed up ioremap, vmalloc and vmap with contiguous memory

[Barry Song]

On Mon, Jul 6, 2026 at 4:43 PM Wen Jiang <jiangwenxiaomi at gmail.com> wrote:
>
> This patchset accelerates ioremap, vmalloc, and vmap when the memory
> is physically fully or partially contiguous. Two techniques are used:
>
> 1. Avoid page table rewalk when setting PTEs/PMDs for multiple memory
>    segments
> 2. Use batched mappings wherever possible in both vmalloc and ARM64
>    layers
>
> Besides accelerating the mapping path, this also enables large
> mappings (PMD and cont-PTE) for vmap, which are currently not
> supported.
>
> Patches 1-2 extend ARM64 vmalloc CONT-PTE mapping to support multiple
> CONT-PTE regions instead of just one.
>
> Patch 3 extracts a common helper vmap_set_ptes() that consolidates PTE
> mapping logic between the ioremap and vmalloc/vmap paths, handling both
> CONT_PTE and regular PTE mappings. This prepares for the next patch.
>
> Patch 4 extends the page table walk path to support page shifts other
> than PAGE_SHIFT and eliminates the page table rewalk for huge vmalloc
> mappings. The function is renamed from vmap_small_pages_range_noflush()
> to vmap_pages_range_noflush_walk().
>
> Patches 5-6 add huge vmap support for contiguous pages, including
> support for non-compound pages with pfn alignment verification.
>
> On the RK3588 8-core ARM64 SoC, with tasks pinned to a little core and
> the performance CPUfreq policy enabled, benchmark results:
>
> * ioremap(1 MB): 1.35x faster (3407 ns -> 2526 ns)
> * vmalloc(1 MB) mapping time (excluding allocation) with
>   VM_ALLOW_HUGE_VMAP: 1.42x faster (5.00 us -> 3.53us)
> * vmap(100MB) with order-8 pages: 8.3x faster (1235 us -> 149 us)
>
> Many thanks to Xueyuan Chen for his testing efforts on RK3588 boards.

Please also put Leo's data here[1] and also please collect Leo's tags in all
patches.

Tested-by: Leo Yan <leo.yan at arm.com>

[1] https://lore.kernel.org/linux-mm/20260626151214.GA1794676@e132581.arm.com/