On Mon, May 7, 2018 at 11:46 AM, Matthew Wilcox <willy@xxxxxxxxxxxxx> wrote: > On Mon, May 07, 2018 at 10:50:21PM +0800, Huaisheng Ye wrote: >> 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. > > You probably want to let linux-nvdimm know about this patch set. > Adding to the cc. Yes, thanks for that! > Also, I only received patch 0 and 4. What happened > to 1-3,5 and 6? > >> 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 I think adding yet one more mm-zone is the wrong direction. Instead, what we have been considering is a mechanism to allow a device-dax instance to be given back to the kernel as a distinct numa node managed by the VM. It seems it times to dust off those patches.
