x86架构22.03SP1版本下物理内存剩余很多还是会swap使用率100%
环境：
5.10.0-136.12.0.86.oe2203sp1.x86_64
~]# lscpu
Architecture: x86_64
CPU op-mode(s): 32-bit, 64-bit
Address sizes: 46 bits physical, 48 bits virtual
Byte Order: Little Endian
CPU(s): 56
On-line CPU(s) list: 0-55
Vendor ID: GenuineIntel
BIOS Vendor ID: Intel(R) Corporation
Model name: Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz
BIOS Model name: Intel(R) Xeon(R) CPU E5-2690 v4 @ 2.60GHz
CPU family: 6
Model: 79
Thread(s) per core: 2
Core(s) per socket: 14
Socket(s): 2
Stepping: 1
CPU max MHz: 3500.0000
CPU min MHz: 1200.0000
BogoMIPS: 5187.71
Flags: fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush dts acpi mmx fxsr sse sse2 ss ht tm pbe syscall nx pdpe1gb rdtscp lm constant_tsc arch_perfmon pebs bts rep_good nopl xtopology
nonstop_tsc cpuid aperfmperf pni pclmulqdq dtes64 ds_cpl vmx smx est tm2 ssse3 sdbg fma cx16 xtpr pdcm pcid dca sse4_1 sse4_2 x2apic movbe popcnt aes xsave avx f16c rdrand lahf_lm abm 3dnowprefetch cpuid_faul
t epb cat_l3 cdp_l3 invpcid_single pti intel_ppin tpr_shadow vnmi flexpriority ept vpid ept_ad fsgsbase tsc_adjust bmi1 hle avx2 smep bmi2 erms invpcid rtm cqm rdt_a rdseed adx smap intel_pt xsaveopt cqm_llc
cqm_occup_llc cqm_mbm_total cqm_mbm_local dtherm ida arat pln pts
Virtualization features:
Virtualization: VT-x
Caches (sum of all):
L1d: 896 KiB (28 instances)
L1i: 896 KiB (28 instances)
L2: 7 MiB (28 instances)
L3: 70 MiB (2 instances)
NUMA:
NUMA node(s): 2
NUMA node0 CPU(s): 0-13,28-41
NUMA node1 CPU(s): 14-27,42-55
场景：MySQL Server
top - 11:24:26 up 403 days, 22:59, 1 user, load average: 4.58, 4.96, 4.96
Tasks: 624 total, 2 running, 621 sleeping, 0 stopped, 1 zombie
%Cpu(s): 3.6 us, 0.7 sy, 0.0 ni, 94.3 id, 1.1 wa, 0.1 hi, 0.3 si, 0.0 st
MiB Mem : 257020.8 total, 9419.8 free, 92875.7 used, 154725.3 buff/cache
MiB Swap: 8192.0 total, 0.4 free, 8191.6 used. 136077.3 avail Mem
PID USER PR NI VIRT RES SHR S %CPU %MEM SWAP TIME+ COMMAND
2175575 mysql 20 0 96.1g 77.4g 10856 S 224.8 30.8 8.0g 89w+0d mysqld
1401 root 20 0 387256 45292 40388 S 0.7 0.0 14744 2w+4d tuned
~]$ cat /proc/cmdline
BOOT_IMAGE=/vmlinuz-5.10.0-136.12.0.86.oe2203sp1.x86_64 root=UUID=84ba7b6b-b2a9-4af4-befa-666ad286b162 ro rhgb quiet crashkernel=auto net.ifnames=1 biosdevname=0 ipv6.disable=1 intel_pstate=enable intel_idle.max_cstate=0 processor.max_cstate=0 sched_steal_node_limit=4 nohz=on audit=0 resume=UUID=066d989b-8036-4912-a60c-a3eab4f24c10 cgroup_disable=files apparmor=0 crashkernel=512M selinux=0
~]# free -m
total used free shared buff/cache available
Mem: 257020 92871 9447 4138 154702 136089
Swap: 8191 8191 0
~]# sysctl -a|grep swap
vm.swappiness = 1
~]# cat /sys/kernel/mm/transparent_hugepage/enabled
always madvise [never]
~]# cat /sys/kernel/mm/transparent_hugepage/defrag
always defer defer+madvise madvise [never]
~]# sysctl -a|grep water
vm.watermark_boost_factor = 15000
vm.watermark_scale_factor = 300
从下图看，分上中下，上图的numa lowest代表2个node里面，最低内存的没有低于1.3G，不存在因为numa关系，某个节点内存不够而使用SWAP
如下图，在free可用内存足够的情况下，swapin，swapout总是会发生
