[#LU-11163] CPT-bound allocations can fail if NUMA node is OOM

With a simple tcp/socklnd configuration there are memory allocation failures even for very small (sub-PAGE_SIZE allocations):

[oss00 ~]# modprobe lustre -v
insmod /lib/modules/3.10.0-693.11.1.el7.x86_64/extra/libcfs.ko
insmod /lib/modules/3.10.0-693.11.1.el7.x86_64/extra/lnet.ko networks=tcp0(ens801)
insmod /lib/modules/3.10.0-693.11.1.el7.x86_64/extra/obdclass.ko
insmod /lib/modules/3.10.0-693.11.1.el7.x86_64/extra/ptlrpc.ko
modprobe: ERROR: could not insert 'lustre': Cannot allocate memory
[oss00 ~]# dmesg
[ 998.653695] libcfs: loading out-of-tree module taints kernel.
[ 998.654085] libcfs: module verification failed: signature and/or required key missing - tainting kernel
[ 998.658330] LNet: HW NUMA nodes: 2, HW CPU cores: 28, npartitions: 2
[ 998.660558] alg: No test for adler32 (adler32-zlib)
[ 998.660606] alg: No test for crc32 (crc32-table)
[ 999.418205] Lustre: Lustre: Build Version: 2.10.1
[ 999.447239] LNet: Added LNI 192.168.99.3@tcp [8/256/0/180]
[ 999.447295] LNet: Accept secure, port 988
[ 999.448457] SLUB: Unable to allocate memory on node 1 (gfp=0x8050)
[ 999.448460] cache: kmalloc-192, object size: 192, buffer size: 192, default order: 1, min order: 0
[ 999.448500] node 0: slabs: 597, objs: 25074, free: 8257
[ 1001.448048] Lustre: 150394:0:(ptlrpcd.c:640:ptlrpcd_stop()) Thread for pc ffff880074f00018 was not started
[ 1001.448066] Lustre: 150394:0:(ptlrpcd.c:659:ptlrpcd_free()) Thread for pc ffff880074f00018 was not started
[ 1003.446986] LustreError: 150394:0:(events.c:631:ptlrpc_init_portals()) rpcd initialisation failed
[ 1004.446991] LNet: Removed LNI 192.168.99.3@tcp

[oss01 tmp]# numactl -H
available: 2 nodes (0-1)
node 0 cpus: 0 1 2 3 4 5 6 7
node 0 size: 32671 MB
node 0 free: 30820 MB
node 1 cpus: 8 9 10 11 12 13 14 15
node 1 size: 0 MB
node 1 free: 0 MB
node distances:
node 0 1
{{ 0: 10 20}}
{{ 1: 20 10}}

but can also happen during normal operations if there is a significant imbalance in allocations between the nodes (e.g. ~~LU-5050~~).

[LU-11163] CPT-bound allocations can fail if NUMA node is OOM Created: 21/Jul/18 Updated: 02/Nov/18 Resolved: 02/Nov/18
Status:	Resolved
Project:	Lustre
Component/s:	None
Affects Version/s:	None
Fix Version/s:	Lustre 2.12.0

[LU-11163] CPT-bound allocations can fail if NUMA node is OOM Created: 21/Jul/18 Updated: 02/Nov/18 Resolved: 02/Nov/18