On Wed, Dec 5, 2018 at 5:43 PM Michal Hocko wrote: > > On Wed 05-12-18 17:29:31, Pingfan Liu wrote: > > On Wed, Dec 5, 2018 at 5:21 PM Michal Hocko wrote: > > > > > > On Wed 05-12-18 13:38:17, Pingfan Liu wrote: > > > > On Tue, Dec 4, 2018 at 4:56 PM Michal Hocko wrote: > > > > > > > > > > On Tue 04-12-18 16:20:32, Pingfan Liu wrote: > > > > > > On Tue, Dec 4, 2018 at 3:22 PM Michal Hocko wrote: > > > > > > > > > > > > > > On Tue 04-12-18 11:05:57, Pingfan Liu wrote: > > > > > > > > During my test on some AMD machine, with kexec -l nr_cpus=x option, the > > > > > > > > kernel failed to bootup, because some node's data struct can not be allocated, > > > > > > > > e.g, on x86, initialized by init_cpu_to_node()->init_memory_less_node(). But > > > > > > > > device->numa_node info is used as preferred_nid param for > > > > > > > > __alloc_pages_nodemask(), which causes NULL reference > > > > > > > > ac->zonelist = node_zonelist(preferred_nid, gfp_mask); > > > > > > > > This patch tries to fix the issue by falling back to the first online node, > > > > > > > > when encountering such corner case. > > > > > > > > > > > > > > We have seen similar issues already and the bug was usually that the > > > > > > > zonelists were not initialized yet or the node is completely bogus. > > > > > > > Zonelists should be initialized by build_all_zonelists quite early so I > > > > > > > am wondering whether the later is the case. What is the actual node > > > > > > > number the device is associated with? > > > > > > > > > > > > > The device's node num is 2. And in my case, I used nr_cpus param. Due > > > > > > to init_cpu_to_node() initialize all the possible node. It is hard > > > > > > for me to figure out without this param, how zonelists is accessed > > > > > > before page allocator works. > > > > > > > > > > I believe we should focus on this. Why does the node have no zonelist > > > > > even though all zonelists should be initialized already? Maybe this is > > > > > nr_cpus pecularity and we do not initialize all the existing numa nodes. > > > > > Or maybe the device is associated to a non-existing node with that > > > > > setup. A full dmesg might help us here. > > > > > > > > > Requiring the machine again, and I got the following without nr_cpus option > > > > [root@dell-per7425-03 ~]# cd /sys/devices/system/node/ > > > > [root@dell-per7425-03 node]# ls > > > > has_cpu has_memory has_normal_memory node0 node1 node2 node3 > > > > node4 node5 node6 node7 online possible power uevent > > > > [root@dell-per7425-03 node]# cat has_cpu > > > > 0-7 > > > > [root@dell-per7425-03 node]# cat has_memory > > > > 1,5 > > > > [root@dell-per7425-03 node]# cat online > > > > 0-7 > > > > [root@dell-per7425-03 node]# cat possible > > > > 0-7 > > > > And lscpu shows the following numa-cpu info: > > > > NUMA node0 CPU(s): 0,8,16,24 > > > > NUMA node1 CPU(s): 2,10,18,26 > > > > NUMA node2 CPU(s): 4,12,20,28 > > > > NUMA node3 CPU(s): 6,14,22,30 > > > > NUMA node4 CPU(s): 1,9,17,25 > > > > NUMA node5 CPU(s): 3,11,19,27 > > > > NUMA node6 CPU(s): 5,13,21,29 > > > > NUMA node7 CPU(s): 7,15,23,31 > > > > > > > > For the full panic message (I masked some hostname info with xx), > > > > please see the attachment. > > > > In a short word, it seems a problem with nr_cpus, if without this > > > > option, the kernel can bootup correctly. > > > > > > Yep. > > > [ 0.007418] Early memory node ranges > > > [ 0.007419] node 1: [mem 0x0000000000001000-0x000000000008efff] > > > [ 0.007420] node 1: [mem 0x0000000000090000-0x000000000009ffff] > > > [ 0.007422] node 1: [mem 0x0000000000100000-0x000000005c3d6fff] > > > [ 0.007422] node 1: [mem 0x00000000643df000-0x0000000068ff7fff] > > > [ 0.007423] node 1: [mem 0x000000006c528000-0x000000006fffffff] > > > [ 0.007424] node 1: [mem 0x0000000100000000-0x000000047fffffff] > > > [ 0.007425] node 5: [mem 0x0000000480000000-0x000000087effffff] > > > > > > There is clearly no node2. Where did the driver get the node2 from? > > Since using nr_cpus=4 , the node2 is not be instanced by x86 initalizing code. > > For the normal bootup, having the following: > > [ 0.007704] Movable zone start for each node > > [ 0.007707] Early memory node ranges > > [ 0.007708] node 1: [mem 0x0000000000001000-0x000000000008efff] > > [ 0.007709] node 1: [mem 0x0000000000090000-0x000000000009ffff] > > [ 0.007711] node 1: [mem 0x0000000000100000-0x000000005c3d6fff] > > [ 0.007712] node 1: [mem 0x00000000643df000-0x0000000068ff7fff] > > [ 0.007712] node 1: [mem 0x000000006c528000-0x000000006fffffff] > > [ 0.007713] node 1: [mem 0x0000000100000000-0x000000047fffffff] > > [ 0.007714] node 5: [mem 0x0000000480000000-0x000000087effffff] > > [ 0.008434] Zeroed struct page in unavailable ranges: 46490 pages > > Hmm, this is even more interesting. So even a normal boot doesn't have > node 2. So where exactly does the device get its affinity from? > I am afraid that there is maybe some misunderstanding, but for the normal bootup, the full boot msg shows the existence of node 2 First, the following can be observed: [ 0.007385] SRAT: PXM 0 -> APIC 0x00 -> Node 0 [ 0.007386] SRAT: PXM 0 -> APIC 0x01 -> Node 0 [ 0.007387] SRAT: PXM 0 -> APIC 0x08 -> Node 0 [ 0.007388] SRAT: PXM 0 -> APIC 0x09 -> Node 0 [ 0.007389] SRAT: PXM 1 -> APIC 0x10 -> Node 1 [ 0.007390] SRAT: PXM 1 -> APIC 0x11 -> Node 1 [ 0.007391] SRAT: PXM 1 -> APIC 0x18 -> Node 1 [ 0.007392] SRAT: PXM 1 -> APIC 0x19 -> Node 1 [ 0.007393] SRAT: PXM 2 -> APIC 0x20 -> Node 2 [ 0.007394] SRAT: PXM 2 -> APIC 0x21 -> Node 2 [ 0.007395] SRAT: PXM 2 -> APIC 0x28 -> Node 2 [ 0.007396] SRAT: PXM 2 -> APIC 0x29 -> Node 2 [ 0.007397] SRAT: PXM 3 -> APIC 0x30 -> Node 3 [ 0.007398] SRAT: PXM 3 -> APIC 0x31 -> Node 3 [ 0.007399] SRAT: PXM 3 -> APIC 0x38 -> Node 3 [ 0.007400] SRAT: PXM 3 -> APIC 0x39 -> Node 3 [ 0.007401] SRAT: PXM 4 -> APIC 0x40 -> Node 4 [ 0.007402] SRAT: PXM 4 -> APIC 0x41 -> Node 4 [ 0.007403] SRAT: PXM 4 -> APIC 0x48 -> Node 4 [ 0.007403] SRAT: PXM 4 -> APIC 0x49 -> Node 4 [ 0.007404] SRAT: PXM 5 -> APIC 0x50 -> Node 5 [ 0.007405] SRAT: PXM 5 -> APIC 0x51 -> Node 5 [ 0.007406] SRAT: PXM 5 -> APIC 0x58 -> Node 5 [ 0.007407] SRAT: PXM 5 -> APIC 0x59 -> Node 5 [ 0.007408] SRAT: PXM 6 -> APIC 0x60 -> Node 6 [ 0.007409] SRAT: PXM 6 -> APIC 0x61 -> Node 6 [ 0.007410] SRAT: PXM 6 -> APIC 0x68 -> Node 6 [ 0.007411] SRAT: PXM 6 -> APIC 0x69 -> Node 6 [ 0.007412] SRAT: PXM 7 -> APIC 0x70 -> Node 7 [ 0.007413] SRAT: PXM 7 -> APIC 0x71 -> Node 7 [ 0.007414] SRAT: PXM 7 -> APIC 0x78 -> Node 7 [ 0.007414] SRAT: PXM 7 -> APIC 0x79 -> Node 7 Second: [ 0.024497] NODE_DATA(2) allocated [mem 0x87ef4b000-0x87ef75fff] [ 0.024498] NODE_DATA(2) on node 5 [ 0.024530] Initmem setup node 2 [mem 0x0000000000000000-0x0000000000000000] Besides these, as I pasted, when normal bootup, lscpu shows the: NUMA node2 CPU(s): 4,12,20,28 and [root@dell-per7425-03 node]# cat has_cpu 0-7 [root@dell-per7425-03 node]# cat has_memory 1,5 So I think node 2 exists, which has cpus but no memory. I attach SRAT, which show there are eight Proximity Domain. As my understanding, each Proximity Domain will correspond to a numa node. Cced acpi guys and hope them can give some hints. > I suspect we are looking at two issues here. The first one, and a more > important one is that there is a NUMA affinity configured for the device > to a non-existing node. The second one is that nr_cpus affects > initialization of possible nodes. The dev->numa_node info is extracted from acpi table, not depends on the instance of numa-node, which may be limited by nr_cpus. Hence the node is existing, just not instanced. Thanks, Pingfan