Re: [PATCH V3 0/3] arm64: Enable vmemmap mapping from device memory

[Jia He]

Hi

On 2020/3/31 13:09, Anshuman Khandual wrote:
> This series enables vmemmap backing memory allocation from device memory
> ranges on arm64. But before that, it enables vmemmap_populate_basepages()
> and vmemmap_alloc_block_buf() to accommodate struct vmem_altmap based
> alocation requests.

I verified no obvious regression after this patch series.

Host: ThunderX2(armv8a server), kernel v5.4

qemu:v3.1, -M virt \

-object 
memory-backend-file,id=mem1,share=on,mem-path=/tmp2/nvdimm.img,size=4G,align=2M \

-device nvdimm,id=nvdimm1,memdev=mem1,label-size=2M

Guest: kernel v5.7.0-rc5 with this patch series.

Tested case:

- 4K PAGESIZE, boot, mount w/ -o dax, mount w/o -o dax, basic io

- 64K PAGESIZE,boot, mount w/ -o dax, mount w/o -o dax, basic io

Not tested:

- 16K pagesize due to my hardware limiation(can't run 16K pgsz kernel)

- hot-add/remove nvdimm device from qemu due to no fully support on arm64 qemu yet

- Host nvdimm device hotplug

Hence from above result,

Tested-by: Jia He <justin.he@xxxxxxx>

> This series applies after latest (v14) arm64 memory hot remove series
> (https://lkml.org/lkml/2020/3/3/1746) on Linux 5.6.
>
> Pending Question:
>
> altmap_alloc_block_buf() does not have any other remaining users in the
> tree after this change. Should it be converted into a static function and
> it's declaration be dropped from the header (include/linux/mm.h). Avoided
> doing so because I was not sure if there are any off-tree users or not.
>
> Changes in V3:
>
> - Dropped comment from free_hotplug_page_range() per Robin
> - Modified comment in unmap_hotplug_range() per Robin
> - Enabled altmap support in vmemmap_alloc_block_buf() per Robin
>
> Changes in V2: (https://lkml.org/lkml/2020/3/4/475)
>
> - Rebased on latest hot-remove series (v14) adding P4D page table support
>
> Changes in V1: (https://lkml.org/lkml/2020/1/23/12)
>
> - Added an WARN_ON() in unmap_hotplug_range() when altmap is
>    provided without the page table backing memory being freed
>
> Changes in RFC V2: (https://lkml.org/lkml/2019/10/21/11)
>
> - Changed the commit message on 1/2 patch per Will
> - Changed the commit message on 2/2 patch as well
> - Rebased on arm64 memory hot remove series (v10)
>
> RFC V1: (https://lkml.org/lkml/2019/6/28/32)
>
> Cc: Catalin Marinas<catalin.marinas@xxxxxxx>
> Cc: Will Deacon<will@xxxxxxxxxx>
> Cc: Mark Rutland<mark.rutland@xxxxxxx>
> Cc: Paul Walmsley<paul.walmsley@xxxxxxxxxx>
> Cc: Palmer Dabbelt<palmer@xxxxxxxxxxx>
> Cc: Tony Luck<tony.luck@xxxxxxxxx>
> Cc: Fenghua Yu<fenghua.yu@xxxxxxxxx>
> Cc: Dave Hansen<dave.hansen@xxxxxxxxxxxxxxx>
> Cc: Andy Lutomirski<luto@xxxxxxxxxx>
> Cc: Peter Zijlstra<peterz@xxxxxxxxxxxxx>
> Cc: Thomas Gleixner<tglx@xxxxxxxxxxxxx>
> Cc: Ingo Molnar<mingo@xxxxxxxxxx>
> Cc: David Hildenbrand<david@xxxxxxxxxx>
> Cc: Mike Rapoport<rppt@xxxxxxxxxxxxx>
> Cc: Michal Hocko<mhocko@xxxxxxxx>
> Cc: "Matthew Wilcox (Oracle)"<willy@xxxxxxxxxxxxx>
> Cc: "Kirill A. Shutemov"<kirill.shutemov@xxxxxxxxxxxxxxx>
> Cc: Andrew Morton<akpm@xxxxxxxxxxxxxxxxxxxx>
> Cc: Dan Williams<dan.j.williams@xxxxxxxxx>
> Cc: Pavel Tatashin<pasha.tatashin@xxxxxxxxxx>
> Cc: Benjamin Herrenschmidt<benh@xxxxxxxxxxxxxxxxxxx>
> Cc: Paul Mackerras<paulus@xxxxxxxxx>
> Cc: Michael Ellerman<mpe@xxxxxxxxxxxxxx>
> Cc:linux-arm-kernel@xxxxxxxxxxxxxxxxxxx
> Cc:linux-ia64@xxxxxxxxxxxxxxx
> Cc:linux-riscv@xxxxxxxxxxxxxxxxxxx
> Cc:x86@xxxxxxxxxx
> Cc:linuxppc-dev@xxxxxxxxxxxxxxxx
> Cc:linux-mm@xxxxxxxxx
> Cc:linux-kernel@xxxxxxxxxxxxxxx
>
> Anshuman Khandual (3):
>    mm/sparsemem: Enable vmem_altmap support in vmemmap_populate_basepages()
>    mm/sparsemem: Enable vmem_altmap support in vmemmap_alloc_block_buf()
>    arm64/mm: Enable vmem_altmap support for vmemmap mappings
>
>   arch/arm64/mm/mmu.c       | 59 ++++++++++++++++++++++++++-------------
>   arch/ia64/mm/discontig.c  |  2 +-
>   arch/powerpc/mm/init_64.c | 10 +++----
>   arch/riscv/mm/init.c      |  2 +-
>   arch/x86/mm/init_64.c     | 12 ++++----
>   include/linux/mm.h        |  8 ++++--
>   mm/sparse-vmemmap.c       | 38 ++++++++++++++++++++-----
>   7 files changed, 87 insertions(+), 44 deletions(-)
--

---
Cheers,
Justin (Jia He)