2

I have "page allocation failure" error occurred on my RHEL7 system. Here it is:

kernel: [85531.010995] sh: page allocation failure: order:4, mode:0x2040d0
kernel: [85531.011000] CPU: 1 PID: 20846 Comm: sh Not tainted 3.10.0-693.el7.AV1.x86_64 #1
kernel: [85531.011002] Hardware name: VMware, Inc. VMware Virtual Platform/440BX Desktop Reference Platform, BIOS 6.00 09/21/2015
kernel: [85531.011003]  00000000002040d0 00000000d00413f4 ffff8800070ffa18 ffffffff816a3e1d
kernel: [85531.011006]  ffff8800070ffaa8 ffffffff81188d00 0000000000000000 ffff88023ffd8000
kernel: [85531.011008]  0000000000000004 00000000002040d0 ffff8800070ffaa8 00000000d00413f4
kernel: [85531.011010] Call Trace:
kernel: [85531.011018]  [] dump_stack+0x19/0x1b
kernel: [85531.011023]  [] warn_alloc_failed+0x110/0x180
kernel: [85531.011026]  [] __alloc_pages_slowpath+0x6b6/0x724
kernel: [85531.011028]  [] __alloc_pages_nodemask+0x405/0x420
kernel: [85531.011031]  [] alloc_pages_current+0x98/0x110
kernel: [85531.011035]  [] new_slab+0x2fc/0x310
kernel: [85531.011037]  [] ___slab_alloc+0x3ac/0x4f0
kernel: [85531.011042]  [] ? copy_process+0x18e/0x19a0
kernel: [85531.011044]  [] ? copy_process+0x18e/0x19a0
kernel: [85531.011046]  [] __slab_alloc+0x40/0x5c
kernel: [85531.011049]  [] kmem_cache_alloc_node+0x8b/0x200
kernel: [85531.011051]  [] copy_process+0x18e/0x19a0
kernel: [85531.011053]  [] do_fork+0x91/0x320
kernel: [85531.011056]  [] SyS_clone+0x16/0x20
kernel: [85531.011059]  [] stub_clone+0x69/0x90
kernel: [85531.011061]  [] ? system_call_fastpath+0x16/0x1b
kernel: [85531.011062] Mem-Info:
kernel: [85531.011066] active_anon:1145227 inactive_anon:278512 isolated_anon:0
kernel: [85531.011066]  active_file:181319 inactive_file:185784 isolated_file:0
kernel: [85531.011066]  unevictable:2695 dirty:4333 writeback:0 unstable:0
kernel: [85531.011066]  slab_reclaimable:45889 slab_unreclaimable:54798
kernel: [85531.011066]  mapped:79471 shmem:52418 pagetables:11994 bounce:0
kernel: [85531.011066]  free:33850 free_pcp:0 free_cma:0
kernel: [85531.011069] Node 0 DMA free:15868kB min:132kB low:164kB high:196kB active_anon:0kB inactive_anon:0kB active_file:0kB inactive_file:0kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:15992kB managed:15908kB mlocked:0kB dirty:0kB writeback:0kB mapped:0kB shmem:0kB slab_reclaimable:0kB slab_unreclaimable:8kB kernel_stack:0kB pagetables:0kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? yes
kernel: [85531.011073] lowmem_reserve[]: 0 2809 7800 7800
kernel: [85531.011076] Node 0 DMA32 free:53892kB min:24292kB low:30364kB high:36436kB active_anon:1622080kB inactive_anon:516652kB active_file:203244kB inactive_file:212104kB unevictable:2312kB isolated(anon):0kB isolated(file):0kB present:3129280kB managed:2878656kB mlocked:2312kB dirty:6236kB writeback:0kB mapped:115972kB shmem:79808kB slab_reclaimable:77740kB slab_unreclaimable:90500kB kernel_stack:13680kB pagetables:17624kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
kernel: [85531.011080] lowmem_reserve[]: 0 0 4990 4990
kernel: [85531.011082] Node 0 Normal free:65640kB min:43152kB low:53940kB high:64728kB active_anon:2958828kB inactive_anon:597396kB active_file:522032kB inactive_file:531032kB unevictable:8468kB isolated(anon):0kB isolated(file):0kB present:5242880kB managed:5110372kB mlocked:8464kB dirty:11096kB writeback:0kB mapped:201912kB shmem:129864kB slab_reclaimable:105816kB slab_unreclaimable:128684kB kernel_stack:19936kB pagetables:30352kB unstable:0kB bounce:0kB free_pcp:0kB local_pcp:0kB free_cma:0kB writeback_tmp:0kB pages_scanned:0 all_unreclaimable? no
kernel: [85531.011085] lowmem_reserve[]: 0 0 0 0
kernel: [85531.011087] Node 0 DMA: 1*4kB (U) 1*8kB (U) 1*16kB (U) 1*32kB (U) 1*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15868kB
kernel: [85531.011095] Node 0 DMA32: 2946*4kB (UEM) 1995*8kB (UEM) 1241*16kB (UEM) 186*32kB (UEM) 9*64kB (U) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 54128kB
kernel: [85531.011102] Node 0 Normal: 16005*4kB (UEM) 248*8kB (UEM) 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 66004kB
kernel: [85531.011108] Node 0 hugepages_total=0 hugepages_free=0 hugepages_surp=0 hugepages_size=2048kB
kernel: [85531.011109] 428930 total pagecache pages
kernel: [85531.011110] 8261 pages in swap cache
kernel: [85531.011111] Swap cache stats: add 51264, delete 43003, find 2892763/2894481
kernel: [85531.011112] Free swap  = 5078128kB
kernel: [85531.011113] Total swap = 5242876kB
kernel: [85531.011114] 2097038 pages RAM
kernel: [85531.011114] 0 pages HighMem/MovableOnly
kernel: [85531.011115] 95804 pages reserved
kernel: [85531.011116] SLUB: Unable to allocate memory on node -1 (gfp=0xd0)
kernel: [85531.011118]   cache: task_struct, object size: 45024, buffer size: 45024, default order: 4, min order: 4
kernel: [85531.011119]   node 0: slabs: 2114, objs: 2114, free: 0

The question is about the latest section of its message:

kernel: [85531.011116] SLUB: Unable to allocate memory on node -1 (gfp=0xd0)
kernel: [85531.011118]   cache: task_struct, object size: 45024, buffer size: 45024, default order: 4, min order: 4
kernel: [85531.011119]   node 0: slabs: 2114, objs: 2114, free: 0

Why does the node index has -1, when allocation fails in Zone from Node 0? That's a bit confusing..

kernel: [85531.011087] Node 0 DMA: 1*4kB (U) 1*8kB (U) 1*16kB (U) 1*32kB (U) 1*64kB (U) 1*128kB (U) 1*256kB (U) 0*512kB 1*1024kB (U) 1*2048kB (M) 3*4096kB (M) = 15868kB
kernel: [85531.011095] Node 0 DMA32: 2946*4kB (UEM) 1995*8kB (UEM) 1241*16kB (UEM) 186*32kB (UEM) 9*64kB (U) 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 54128kB
kernel: [85531.011102] Node 0 Normal: 16005*4kB (UEM) 248*8kB (UEM) 0*16kB 0*32kB 0*64kB 0*128kB 0*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 66004kB
2

Node -1 means "any node". You probably only have one node. Red Hat's kernel is configured so it will run on single-node machines by emulating a NUMA machine with just one node. Check your boot log (/var/log/dmesg). I have:

[    0.000000] No NUMA configuration found
[    0.000000] Faking a node at [mem 0x0000000000000000-0x000000023bffffff]
  • That makes sense, thank you! I don't have such entries in my dmesg, but my machine has 1 node for sure. – sys463 Jun 27 '18 at 19:23

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