mm/memcontrol: do not tweak node in mem_cgroup_init()

mm/memcontrol: do not tweak node in mem_cgroup_init()

mem_cgroup_init() request for allocations from each possible node, and
it's used to be a problem because NODE_DATA is not allocated for offline
node. Things have already changed since commit 09f49dca570a9 ("mm: handle
uninitialized numa nodes gracefully"), so it's unnecessary to check for
!node_online nodes here.

How to test?

qemu-system-x86_64 \
  -kernel vmlinux \
  -initrd full.rootfs.cpio.gz \
  -append "console=ttyS0,115200 root=/dev/ram0 nokaslr earlyprintk=serial oops=panic panic_on_warn" \
  -drive format=qcow2,file=vm_disk.qcow2,media=disk,if=ide \
  -enable-kvm \
  -cpu host \
  -m 8G,slots=2,maxmem=16G \
  -smp cores=4,threads=1,sockets=2  \
  -object memory-backend-ram,id=mem0,size=4G \
  -object memory-backend-ram,id=mem1,size=4G \
  -numa node,memdev=mem0,cpus=0-3,nodeid=0 \
  -numa node,memdev=mem1,cpus=4-7,nodeid=1 \
  -numa node,nodeid=2 \
  -net nic,model=virtio,macaddr=52:54:00:12:34:58 \
  -net user \
  -nographic \
  -rtc base=localtime \
  -gdb tcp::6000

Guest state when booting:

[    0.048881] NUMA: Node 0 [mem 0x00000000-0x0009ffff] + [mem 0x00100000-0xbfffffff] -> [mem 0x00000000-0xbfffffff]
[    0.050489] NUMA: Node 0 [mem 0x00000000-0xbfffffff] + [mem 0x100000000-0x13fffffff] -> [mem 0x00000000-0x13fffffff]
[    0.052173] NODE_DATA(0) allocated [mem 0x13fffc000-0x13fffffff]
[    0.053164] NODE_DATA(1) allocated [mem 0x23fffa000-0x23fffdfff]
[    0.054187] Zone ranges:
[    0.054587]   DMA      [mem 0x0000000000001000-0x0000000000ffffff]
[    0.055551]   DMA32    [mem 0x0000000001000000-0x00000000ffffffff]
[    0.056515]   Normal   [mem 0x0000000100000000-0x000000023fffffff]
[    0.057484] Movable zone start for each node
[    0.058149] Early memory node ranges
[    0.058705]   node   0: [mem 0x0000000000001000-0x000000000009efff]
[    0.059679]   node   0: [mem 0x0000000000100000-0x00000000bffdffff]
[    0.060659]   node   0: [mem 0x0000000100000000-0x000000013fffffff]
[    0.061649]   node   1: [mem 0x0000000140000000-0x000000023fffffff]
[    0.062638] Initmem setup node 0 [mem 0x0000000000001000-0x000000013fffffff]
[    0.063745] Initmem setup node 1 [mem 0x0000000140000000-0x000000023fffffff]
[    0.064855]   DMA zone: 158 reserved pages exceeds freesize 0
[    0.065746] Initializing node 2 as memoryless
[    0.066437] Initmem setup node 2 as memoryless
[    0.067132]   DMA zone: 158 reserved pages exceeds freesize 0
[    0.068037] On node 0, zone DMA: 1 pages in unavailable ranges
[    0.068265] On node 0, zone DMA: 97 pages in unavailable ranges
[    0.124755] On node 0, zone Normal: 32 pages in unavailable ranges

cat /sys/devices/system/node/online
0-1
cat /sys/devices/system/node/possible
0-2

Link: https://lkml.kernel.org/r/20230619130442.2487-1-haifeng.xu@shopee.com
Signed-off-by: Haifeng Xu <haifeng.xu@shopee.com>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Shakeel Butt <shakeelb@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>