> From: owner-linux-mm@xxxxxxxxx [mailto:owner-linux-mm@xxxxxxxxx] On Behalf Of Michal Hocko > > On Wed 09-05-18 04:22:10, Huaisheng HS1 Ye wrote: > > > > > On 05/07/2018 07:33 PM, Huaisheng HS1 Ye wrote: > > > > diff --git a/mm/Kconfig b/mm/Kconfig > > > > index c782e8f..5fe1f63 100644 > > > > --- a/mm/Kconfig > > > > +++ b/mm/Kconfig > > > > @@ -687,6 +687,22 @@ config ZONE_DEVICE > > > > > > > > +config ZONE_NVM > > > > + bool "Manage NVDIMM (pmem) by memory management (EXPERIMENTAL)" > > > > + depends on NUMA && X86_64 > > > > > > Hi, > > > I'm curious why this depends on NUMA. Couldn't it be useful in non-NUMA > > > (i.e., UMA) configs? > > > > > I wrote these patches with two sockets testing platform, and there are two DDRs and > two NVDIMMs have been installed to it. > > So, for every socket it has one DDR and one NVDIMM with it. Here is memory region > from memblock, you can get its distribution. > > > > 435 [ 0.000000] Zone ranges: > > 436 [ 0.000000] DMA [mem 0x0000000000001000-0x0000000000ffffff] > > 437 [ 0.000000] DMA32 [mem 0x0000000001000000-0x00000000ffffffff] > > 438 [ 0.000000] Normal [mem 0x0000000100000000-0x00000046bfffffff] > > 439 [ 0.000000] NVM [mem 0x0000000440000000-0x00000046bfffffff] > > 440 [ 0.000000] Device empty > > 441 [ 0.000000] Movable zone start for each node > > 442 [ 0.000000] Early memory node ranges > > 443 [ 0.000000] node 0: [mem 0x0000000000001000-0x000000000009ffff] > > 444 [ 0.000000] node 0: [mem 0x0000000000100000-0x00000000a69c2fff] > > 445 [ 0.000000] node 0: [mem 0x00000000a7654000-0x00000000a85eefff] > > 446 [ 0.000000] node 0: [mem 0x00000000ab399000-0x00000000af3f6fff] > > 447 [ 0.000000] node 0: [mem 0x00000000af429000-0x00000000af7fffff] > > 448 [ 0.000000] node 0: [mem 0x0000000100000000-0x000000043fffffff] Normal 0 > > 449 [ 0.000000] node 0: [mem 0x0000000440000000-0x000000237fffffff] NVDIMM 0 > > 450 [ 0.000000] node 1: [mem 0x0000002380000000-0x000000277fffffff] Normal 1 > > 451 [ 0.000000] node 1: [mem 0x0000002780000000-0x00000046bfffffff] NVDIMM 1 > > > > If we disable NUMA, there is a result as Normal an NVDIMM zones will be overlapping > with each other. > > Current mm treats all memory regions equally, it divides zones just by size, like > 16M for DMA, 4G for DMA32, and others above for Normal. > > The spanned range of all zones couldn't be overlapped. > > No, this is not correct. Zones can overlap. Hi Michal, Thanks for pointing it out. But function zone_sizes_init decides arch_zone_lowest/highest_possible_pfn's size by max_low_pfn, then free_area_init_nodes/node are responsible for calculating the spanned size of zones from memblock memory regions. So, ZONE_DMA and ZONE_DMA32 and ZONE_NORMAL have separate address scope. How can they be overlapped with each other? Sincerely, Huaisheng Ye | 叶怀胜 Linux kernel | Lenovo
