斐讯K2无法运行KCPTUN占用CPU特别高的问题
斐讯K2配置KCPTUN后，CPU就变得特别的忙，高达100%,反应特别慢。
观察日志，发现内存溢出了:
[RT-AC54U /tmp]# tail -f syslog.log
...
Feb 16 09:16:02 kernel: crond invoked oom-killer: gfp_mask=0x201da, order=0, oom_adj=0, oom_score_adj=0
Feb 16 09:16:02 kernel: Call Trace:[] 0x83728000
Feb 16 09:16:02 kernel: [] 0x8027b8ec
Feb 16 09:16:02 kernel: [] 0x80069e94
Feb 16 09:16:02 kernel: [] 0x8006a1f8
Feb 16 09:16:02 kernel: [] 0x8006ddf4
Feb 16 09:16:02 kernel: [] 0x80069da8
Feb 16 09:16:02 kernel: [] 0x8006a430
Feb 16 09:16:02 kernel: [] 0x8006e5c4
Feb 16 09:16:02 kernel: [] 0x80067030
Feb 16 09:16:02 kernel: [] 0x80080644
Feb 16 09:16:02 kernel: [] 0x800804c8
Feb 16 09:16:02 kernel: [] 0x800a0648
Feb 16 09:16:02 kernel: [] 0x80082494
Feb 16 09:16:02 kernel: [] 0x8004ccb0
Feb 16 09:16:02 kernel: [] 0x8027d334
Feb 16 09:16:02 kernel: [] 0x800831c0
Feb 16 09:16:02 kernel: [] 0x80012ee8
Feb 16 09:16:02 kernel: [] 0x80046114
Feb 16 09:16:02 kernel: [] 0x800451a0
Feb 16 09:16:02 kernel: [] 0x800099a0
Feb 16 09:16:02 kernel: Mem-Info:
Feb 16 09:16:02 kernel: Normal per-cpu:
Feb 16 09:16:02 kernel: CPU 0: hi: 18, btch: 3 usd: 17
Feb 16 09:16:02 kernel: active_anon:9393 inactive_anon:397 isolated_anon:0
Feb 16 09:16:02 kernel: active_file:6 inactive_file:13 isolated_file:0
Feb 16 09:16:02 kernel: unevictable:0 dirty:0 writeback:0 unstable:0
Feb 16 09:16:02 kernel: free:1021 slab_reclaimable:320 slab_unreclaimable:1921
Feb 16 09:16:02 kernel: mapped:1 shmem:2047 pagetables:158 bounce:0
Feb 16 09:16:02 kernel: Normal free:4084kB min:4096kB low:5120kB high:6144kB active_anon:37572kB inactive_anon:1588kB active_file:24kB inactive_file:52kB unevictable:0kB isolated(anon):0kB isolated(file):0kB present:65024kB mlocked:0kB dirty:0kB writeback:0kB mapped:4kB shmem:8188kB slab_reclaimable:1280kB slab_unreclaimable:7684kB kernel_stack:568kB pagetables:632kB unstable:0kB bounce:0kB writeback_tmp:0kB pages_scanned:144 all_unreclaimable? yes
Feb 16 09:16:02 kernel: lowmem_reserve[]: 0 0
Feb 16 09:16:02 kernel: Normal: 29*4kB 44*8kB 32*16kB 27*32kB 9*64kB 9*128kB 2*256kB 0*512kB 0*1024kB 0*2048kB 0*4096kB = 4084kB
Feb 16 09:16:02 kernel: 2066 total pagecache pages
Feb 16 09:16:02 kernel: 16384 pages RAM
Feb 16 09:16:02 kernel: 929 pages reserved
Feb 16 09:16:02 kernel: 291 pages shared
Feb 16 09:16:02 kernel: 13441 pages non-shared
Feb 16 09:16:02 kernel: [ pid ] uid tgid total_vm rss cpu oom_adj oom_score_adj name
Feb 16 09:16:02 kernel: [ 290] 0 290 385 16 0 0 0 syslogd
Feb 16 09:16:02 kernel: [ 292] 0 292 385 17 0 0 0 klogd
Feb 16 09:16:02 kernel: [ 355] 0 355 330 23 0 -17 -1000 detect_link
Feb 16 09:16:02 kernel: [ 357] 0 357 330 23 0 -17 -1000 detect_internet
Feb 16 09:16:02 kernel: [ 398] 0 398 388 20 0 0 0 udhcpc
Feb 16 09:16:02 kernel: [ 433] 0 433 390 21 0 0 0 dhcp6c
Feb 16 09:16:02 kernel: [ 446] 0 446 1540 99 0 0 0 httpd
Feb 16 09:16:02 kernel: [ 450] 0 450 373 104 0 0 0 dropbear
Feb 16 09:16:02 kernel: [ 452] 0 452 330 24 0 -17 -1000 watchdog
Feb 16 09:16:02 kernel: [ 456] 0 456 245 32 0 0 0 lld2d
Feb 16 09:16:02 kernel: [ 462] 0 462 216 18 0 0 0 networkmap
Feb 16 09:16:02 kernel: [ 464] 0 464 373 67 0 -17 -1000 rstats
Feb 16 09:16:02 kernel: [ 468] 0 468 389 21 0 0 0 sh
Feb 16 09:16:02 kernel: [ 2211] 0 2211 219 25 0 0 0 bwmon
Feb 16 09:16:02 kernel: [ 8431] 0 8431 168091 2930 0 0 0 frpc
Feb 16 09:16:02 kernel: [10803] 0 10803 380 111 0 0 0 dropbear
Feb 16 09:16:02 kernel: [10804] 0 10804 391 25 0 0 0 sh
Feb 16 09:16:02 kernel: [16450] 0 16450 386 15 0 0 0 tail
Feb 16 09:16:02 kernel: [18483] 0 18483 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18494] 0 18494 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18528] 0 18528 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18558] 0 18558 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18598] 0 18598 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18608] 0 18608 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18642] 0 18642 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [18673] 0 18673 384 13 0 0 0 sleep
Feb 16 09:16:02 kernel: [21569] 0 21569 168267 3599 0 0 0 client_linux_mi
Feb 16 09:16:02 kernel: [21783] 0 21783 387 18 0 0 0 crond
Feb 16 09:16:02 kernel: [22005] 0 22005 210 23 0 0 0 dnsproxy
Feb 16 09:16:02 kernel: [22136] 0 22136 473 109 0 0 0 Sh15_ss.sh
Feb 16 09:16:02 kernel: [22138] 0 22138 698 94 0 0 0 ss-redir
Feb 16 09:16:02 kernel: [22162] 0 22162 210 25 0 0 0 dns_tmp_proxy
Feb 16 09:16:02 kernel: [22177] 99 22177 263 36 0 0 0 dnsmasq
Feb 16 09:16:02 kernel: [22257] 0 22257 473 109 0 0 0 Sh15_ss.sh
Feb 16 09:16:02 kernel: [22261] 0 22261 473 109 0 0 0 Sh15_ss.sh
Feb 16 09:16:02 kernel: [22273] 0 22273 781 62 0 0 0 curl
Feb 16 09:16:02 kernel: [22274] 0 22274 386 16 0 -17 -1000 _opt_script_che
Feb 16 09:16:02 kernel: [22275] 0 22275 781 62 0 0 0 curl
Feb 16 09:16:02 kernel: [22276] 0 22276 387 17 0 -17 -1000 sh
Feb 16 09:16:02 kernel: [22277] 0 22277 385 14 0 -17 -1000 killall
Feb 16 09:16:02 kernel: Out of memory: Kill process 21569 (client_linux_mi) score 203 or sacrifice child
Feb 16 09:16:02 kernel: Killed process 21569 (client_linux_mi) total-vm:673068kB, anon-rss:14396kB, file-rss:0kB
Feb 16 09:25:56 dropbear[23558]: Child connection from 192.168.123.55:50521
...
可以看到最后三行是干掉了KCPTUN的客户端：
Feb 16 09:16:02 kernel: Out of memory: Kill process 21569 (client_linux_mi) score 203 or sacrifice child
Feb 16 09:16:02 kernel: Killed process 21569 (client_linux_mi) total-vm:673068kB, anon-rss:14396kB, file-rss:0kB
Feb 16 09:25:56 dropbear[23558]: Child connection from 192.168.123.55:50521
有人说设置窗口为128可以降低内存使用率，我暂时还没有实验。
我采用的办法是在k2调用wan口联机的电脑上的kcptun服务，目前可以愉快的上网。
主要是用于小米国际版的安装的初始化。
作者：net_wolf
