Understanding kernel memory usage

Installing and Using OpenWrt
1

Hi everyone,
I've got a dir-869-a1 (64MB ram and 8 MB flash) running OpenWRT 19.07.2.
The kernel regulary kills processes because it is out of memory, but I don't
understand why. I enclose the output of free, df, ps and /proc/meminfo.
All processes use about 14MB of ram. tmpfs adds another 500KB.
What is causing the excessive memory usage on my device?

Fri Apr  3 05:45:03 UTC 2020
              total        used        free      shared  buff/cache   available
Mem:          59648       47496       10056          64        2096           0
Swap:             0           0           0
Filesystem                Size      Used Available Use% Mounted on
/dev/root                 3.0M      3.0M         0 100% /rom
tmpfs                    29.1M     64.0K     29.1M   0% /tmp
/dev/mtdblock7           11.0M    432.0K     10.6M   4% /overlay
overlayfs:/overlay       11.0M    432.0K     10.6M   4% /
tmpfs                   512.0K         0    512.0K   0% /dev
  PID USER       VSZ STAT COMMAND
    1 root      1556 S    /sbin/procd
    2 root         0 SW   [kthreadd]
    4 root         0 IW<  [kworker/0:0H]
    5 root         0 IW   [kworker/u2:0]
    6 root         0 IW<  [mm_percpu_wq]
    7 root         0 SW   [ksoftirqd/0]
   84 root         0 SW   [oom_reaper]
   85 root         0 IW<  [writeback]
   87 root         0 SW   [kcompactd0]
   88 root         0 IW<  [crypto]
   90 root         0 IW<  [kblockd]
  108 root         0 IW<  [watchdogd]
  129 root         0 SW   [kswapd0]
  188 root         0 SW   [spi0]
  376 root         0 IW<  [ipv6_addrconf]
  378 root         0 IW<  [dsa_ordered]
  385 root         0 IW<  [kworker/0:1H]
  431 root         0 SWN  [jffs2_gcd_mtd7]
  501 root      1216 S    /sbin/ubusd
  502 root       924 S    /sbin/askfirst /usr/libexec/login.sh
  519 root      1028 S    /sbin/urngd
  596 root         0 IW<  [cfg80211]
  623 root         0 IW<  [ath10k_wq]
  624 root         0 IW<  [ath10k_aux_wq]
  965 root      1248 S    /sbin/logd -S 64
 1090 root      1452 S    /usr/sbin/odhcpd
 1118 root      1216 S    /usr/sbin/crond -f -c /etc/crontabs -l 5
 1303 root      1216 S<   /usr/sbin/ntpd -n -N -S /usr/sbin/ntpd-hotplug -p 0.
 1308 root         0 IW   [kworker/0:4]
 1464 root      1080 S    /usr/sbin/dropbear -F -P /var/run/dropbear.1.pid -s
 2159 root         0 IW   [kworker/u2:1]
 2609 root         0 IW   [kworker/0:0]
 2813 root      1148 S    /usr/sbin/dropbear -F -P /var/run/dropbear.1.pid -s
 2814 root      1212 S    ash -c printf %80s |tr " " "=" | echo $(cat -) && da
 2822 root      1212 R    ps
MemTotal:          59648 kB
MemFree:           10008 kB
MemAvailable:          0 kB
Buffers:             692 kB
Cached:             1412 kB
SwapCached:            0 kB
Active:             2024 kB
Inactive:            824 kB
Active(anon):        784 kB
Inactive(anon):       24 kB
Active(file):       1240 kB
Inactive(file):      800 kB
Unevictable:           0 kB
Mlocked:               0 kB
SwapTotal:             0 kB
SwapFree:              0 kB
Dirty:                 0 kB
Writeback:             0 kB
AnonPages:           756 kB
Mapped:             1256 kB
Shmem:                64 kB
Slab:               5364 kB
SReclaimable:        644 kB
SUnreclaim:         4720 kB
KernelStack:         280 kB
PageTables:          172 kB
NFS_Unstable:          0 kB
Bounce:                0 kB
WritebackTmp:          0 kB
CommitLimit:       29824 kB
Committed_AS:       2468 kB
VmallocTotal:    1048372 kB
VmallocUsed:           0 kB
VmallocChunk:          0 kB
2

what is this?

3

That's a script to save the output you see above on my computer.

4

Which ath10k kmod are you running? ath10k-ct-smallbuffers was made for this situation on a 64M device. The not smallbuffers version will use up all the RAM and crash the router like you are experiencing.

5

I'm using the IMAGEBUILDER to create a custom image
(as you can see I've got no LUCI or dnsmasq).
opkg list-installed tells me kmod-ath10k-ct
I guess that's my error. Thank you very much @mk24