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

From: Jia He <jiakernel2@gmail.com>
To: Anshuman Khandual <anshuman.khandual@arm.com>, linux-mm@kvack.org
Cc: robin.murphy@arm.com, dan.j.williams@intel.com,
	jglisse@redhat.com, jgg@mellanox.com, rcampbell@nvidia.com,
	aneesh.kumar@linux.ibm.com,
	Catalin Marinas <catalin.marinas@arm.com>,
	Will Deacon <will@kernel.org>,
	Mark Rutland <mark.rutland@arm.com>,
	Paul Walmsley <paul.walmsley@sifive.com>,
	Palmer Dabbelt <palmer@dabbelt.com>,
	Tony Luck <tony.luck@intel.com>,
	Fenghua Yu <fenghua.yu@intel.com>,
	Dave Hansen <dave.hansen@linux.intel.com>,
	Andy Lutomirski <luto@kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Thomas Gleixner <tglx@linutronix.de>,
	Ingo Molnar <mingo@redhat.com>,
	David Hildenbrand <david@redhat.com>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Michal Hocko <mhocko@suse.com>,
	"Matthew Wilcox (Oracle)" <willy@infradead.org>,
	"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Pavel Tatashin <pasha.tatashin@soleen.com>,
	Benjamin Herrenschmidt <benh@kernel.crashing.org>,
	Paul Mackerras <paulus@samba.org>,
	Michael Ellerman <mpe@ellerman.id.au>,
	linux-arm-kernel@lists.infradead.org, linux-ia64@vger.kernel.org,
	linux-riscv@lists.infradead.org, x86@kernel.org,
	linuxppc-dev@lists.ozlabs.org, linux-kernel@vger.kernel.org,
	Kaly Xin <Kaly.Xin@arm.com>
Subject: Re: [PATCH V3 0/3] arm64: Enable vmemmap mapping from device memory
Date: Fri, 22 May 2020 11:58:06 +0800	[thread overview]
Message-ID: <4853d33f-d524-8209-4f8d-c26ee1eaa85b@gmail.com> (raw)
In-Reply-To: <1585631387-18819-1-git-send-email-anshuman.khandual@arm.com>

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@arm.com>

> 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@arm.com>
> Cc: Will Deacon<will@kernel.org>
> Cc: Mark Rutland<mark.rutland@arm.com>
> Cc: Paul Walmsley<paul.walmsley@sifive.com>
> Cc: Palmer Dabbelt<palmer@dabbelt.com>
> Cc: Tony Luck<tony.luck@intel.com>
> Cc: Fenghua Yu<fenghua.yu@intel.com>
> Cc: Dave Hansen<dave.hansen@linux.intel.com>
> Cc: Andy Lutomirski<luto@kernel.org>
> Cc: Peter Zijlstra<peterz@infradead.org>
> Cc: Thomas Gleixner<tglx@linutronix.de>
> Cc: Ingo Molnar<mingo@redhat.com>
> Cc: David Hildenbrand<david@redhat.com>
> Cc: Mike Rapoport<rppt@linux.ibm.com>
> Cc: Michal Hocko<mhocko@suse.com>
> Cc: "Matthew Wilcox (Oracle)"<willy@infradead.org>
> Cc: "Kirill A. Shutemov"<kirill.shutemov@linux.intel.com>
> Cc: Andrew Morton<akpm@linux-foundation.org>
> Cc: Dan Williams<dan.j.williams@intel.com>
> Cc: Pavel Tatashin<pasha.tatashin@soleen.com>
> Cc: Benjamin Herrenschmidt<benh@kernel.crashing.org>
> Cc: Paul Mackerras<paulus@samba.org>
> Cc: Michael Ellerman<mpe@ellerman.id.au>
> Cc:linux-arm-kernel@lists.infradead.org
> Cc:linux-ia64@vger.kernel.org
> Cc:linux-riscv@lists.infradead.org
> Cc:x86@kernel.org
> Cc:linuxppc-dev@lists.ozlabs.org
> Cc:linux-mm@kvack.org
> Cc:linux-kernel@vger.kernel.org
>
> 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)