Traditionally, NVDIMMs are treated by mm(memory management) subsystem as
DEVICE zone, which is a virtual zone and both its start and end of pfn
are equal to 0, mm wouldn’t manage NVDIMM directly as DRAM, kernel uses
corresponding drivers, which locate at \drivers\nvdimm\ and
\drivers\acpi\nfit and fs, to realize NVDIMM memory alloc and free with
memory hot plug implementation.
With current kernel, many mm’s classical features like the buddy
system, swap mechanism and page cache couldn’t be supported to NVDIMM.
What we are doing is to expand kernel mm’s capacity to make it to handle
NVDIMM like DRAM. Furthermore we make mm could treat DRAM and NVDIMM
separately, that means mm can only put the critical pages to NVDIMM
zone, here we created a new zone type as NVM zone. That is to say for
traditional(or normal) pages which would be stored at DRAM scope like
Normal, DMA32 and DMA zones. But for the critical pages, which we hope
them could be recovered from power fail or system crash, we make them
to be persistent by storing them to NVM zone.
We installed two NVDIMMs to Lenovo Thinksystem product as development
platform, which has 125GB storage capacity respectively. With these
patches below, mm can create NVM zones for NVDIMMs.
Here is dmesg info,
Initmem setup node 0 [mem 0x0000000000001000-0x000000237fffffff]
On node 0 totalpages: 36879666
DMA zone: 64 pages used for memmap
DMA zone: 23 pages reserved
DMA zone: 3999 pages, LIFO batch:0
mminit::memmap_init Initialising map node 0 zone 0 pfns 1 -> 4096
DMA32 zone: 10935 pages used for memmap
DMA32 zone: 699795 pages, LIFO batch:31
mminit::memmap_init Initialising map node 0 zone 1 pfns 4096 -> 1048576
Normal zone: 53248 pages used for memmap
Normal zone: 3407872 pages, LIFO batch:31
mminit::memmap_init Initialising map node 0 zone 2 pfns 1048576 -> 4456448
NVM zone: 512000 pages used for memmap
NVM zone: 32768000 pages, LIFO batch:31
mminit::memmap_init Initialising map node 0 zone 3 pfns 4456448 -> 37224448
Initmem setup node 1 [mem 0x0000002380000000-0x00000046bfffffff]
On node 1 totalpages: 36962304
Normal zone: 65536 pages used for memmap
Normal zone: 4194304 pages, LIFO batch:31
mminit::memmap_init Initialising map node 1 zone 2 pfns 37224448 -> 41418752
NVM zone: 512000 pages used for memmap
NVM zone: 32768000 pages, LIFO batch:31
mminit::memmap_init Initialising map node 1 zone 3 pfns 41418752 -> 74186752
This comes /proc/zoneinfo
Node 0, zone NVM
pages free 32768000
min 15244
low 48012
high 80780
spanned 32768000
present 32768000
managed 32768000
protection: (0, 0, 0, 0, 0, 0)
nr_free_pages 32768000
Node 1, zone NVM
pages free 32768000
min 15244
low 48012
high 80780
spanned 32768000
present 32768000
managed 32768000
Huaisheng Ye (6):
mm/memblock: Expand definition of flags to support NVDIMM
mm/page_alloc.c: get pfn range with flags of memblock
mm, zone_type: create ZONE_NVM and fill into GFP_ZONE_TABLE
arch/x86/kernel: mark NVDIMM regions from e820_table
mm: get zone spanned pages separately for DRAM and NVDIMM
arch/x86/mm: create page table mapping for DRAM and NVDIMM both
arch/x86/include/asm/e820/api.h | 3 +++
arch/x86/kernel/e820.c | 20 +++++++++++++-
arch/x86/kernel/setup.c | 8 ++++++
arch/x86/mm/init_64.c | 16 +++++++++++
include/linux/gfp.h | 57 ++++++++++++++++++++++++++++++++++++---
include/linux/memblock.h | 19 +++++++++++++
include/linux/mm.h | 4 +++
include/linux/mmzone.h | 3 +++
mm/Kconfig | 16 +++++++++++
mm/memblock.c | 46 +++++++++++++++++++++++++++----
mm/nobootmem.c | 5 ++--
mm/page_alloc.c | 60 ++++++++++++++++++++++++++++++++++++++++-
12 files changed, 245 insertions(+), 12 deletions(-)
--
1.8.3.1
