Enable Cgroup Memory & Swap Limit

 * memsw disabled by default

查看 Kernel 是否支援 cgroup swap

D10:

grep CONFIG_MEMCG_SWAP /boot/config-`uname -r`

CONFIG_MEMCG_SWAP=y
# CONFIG_MEMCG_SWAP_ENABLED is not set

U14:

grep CONFIG_MEMCG_SWAP /boot/config-`uname -r`

CONFIG_MEMCG_SWAP=y
# CONFIG_MEMCG_SWAP_ENABLED is not set

C6:

grep CGROUP_MEM /boot/config-`uname -r`

CONFIG_CGROUP_MEM_RES_CTLR=y
CONFIG_CGROUP_MEM_RES_CTLR_SWAP=y

啟用

C7 / C8

grep CONFIG_MEMCG_SWAP /boot/config-*

/boot/config-4.18.0-348.20.1.el8_5.x86_64:CONFIG_MEMCG_SWAP=y

/etc/default/grub

GRUB_CMDLINE_LINUX_DEFAULT=" ... cgroup_enable=memory swapaccount=1"

update-grub                                            # C7

grub2-mkconfig > /boot/grub2/grub.cfg    # C8

reboot

測試

ls /sys/fs/cgroup/memory | grep memsw

memory.memsw.failcnt
memory.memsw.limit_in_bytes
memory.memsw.max_usage_in_bytes
memory.memsw.usage_in_bytes

# 假設有 vps: lamp 在行

grep swap /sys/fs/cgroup/memory/lxc/lamp/memory.stat

# swapaccount=1 後才有

swap 42004480           # swap usage, in bytes
total_swap 42004480

swap 的 pgpgin & pgpgout

grep pgpg /sys/fs/cgroup/memory/lxc/lamp/memory.stat

pgpgin 131322329
pgpgout 131267592       # number of pages paged out of memory

Memory Usage

On Hypervisor

/sys/fs/cgroup/memory/lxc.payload/VPS_NAME

• memory.limit_in_bytes
• memory.memsw.limit_in_bytes
• memory.usage_in_bytes
• memory.memsw.usage_in_bytes

On Guest

cat /proc/swaps

Filename                                Type            Size    Used    Priority
none                                    virtual         1048576 20      0

grep -e MemTotal -e SwapTotal /proc/meminfo

MemTotal:        1048576 kB
SwapTotal:       1678332 kB