[步骤] Linux GRUB2 排错模式的开启

步骤一:修改 /ETC/DEFAULT/GRUB 配置文件

# vim /etc/default/grub

在这一行里:

GRUB_CMDLINE_LINUX="......"

添加:

GRUB_CMDLINE_LINUX="...... systemd.default_timeout_start_sec=500s"

步骤二:使刚刚的修改生效

# grub2-mkconfig -o /boot/grub2/grub.cfg

[CONTENT] System local ports batch occupation

Content One: Occupy system local ports manually

# startport=33000;endport=34000;for i in $(seq $startport $endport);do nc -lk $i &;done

(Add: Take start port is 33000 and end port is 34000 as an example here)

Content Two: Release all ports which are opened manually (kill all nc command processes)

# for i in $(ps -aux | grep nc | grep '\-lk' | awk '{print $2}');do kill $i; done

[步骤] Linux page_owner 排查工具的使用 (记录内存的使用情况)

正文:

步骤一:查看 page_owner 是否开启

1.1 通过 dmesg 命令查看 page_owner 是否开启

# dmesg | grep page_owner
[    1.149165] page_owner is disabled

(补充:当显示此类信息时则 page_owner 没有开启)

1.2 通过 /sys/kernel/debug/ 目录查看 page_ownerr 是否开启

# ls -l /sys/kernel/debug/page_owner
ls: cannot access /sys/kernel/debug/page_owner: No such file or directory.

(补充:当 /sys/kernel/debug/page_owner 文件不存在时则 page_owner 没有开启)

步骤二:开启 page_owner

2.1 开启 page_owner

# grubby --args="page_owner=on" --update-kernel=0

(注意:开启 page_owner 会额外占用一定量的内存)

2.2 重启系统

# reboot

2.3 确认 page_owner 已经开启

2.3.1 通过 dmesg 命令确认 page_owner 是否开启
# dmesg | grep page_owner
[    0.000000] Command line: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-4.18.0-425.19.2.el8_7.x86_64 root=/dev/mapper/rootvg-rootlv ro ipv6.disable=1 audit=1 audit_backlog_limit=8192 crashkernel=auto resume=/dev/mapper/rootvg-swaplv rd.lvm.lv=rootvg/rootlv rd.lvm.lv=rootvg/swaplv rhgb quiet rd.shell=0 page_owner=on
[    0.000000] Kernel command line: BOOT_IMAGE=(hd0,gpt2)/vmlinuz-4.18.0-425.19.2.el8_7.x86_64 root=/dev/mapper/rootvg-rootlv ro ipv6.disable=1 audit=1 audit_backlog_limit=8192 crashkernel=auto resume=/dev/mapper/rootvg-swaplv rd.lvm.lv=rootvg/rootlv rd.lvm.lv=rootvg/swaplv rhgb quiet rd.shell=0 page_owner=o

(补充:当显示此类信息时则 page_owner 已经开启)

2.3.2 通过 /sys/kernel/debug/ 目录确认 page_ownerr 是否开启
# ls -l /sys/kernel/debug/page_owner
-r--------. 1 root root 0 Apr 13 14:36 /sys/kernel/debug/page_owner

(补充:当 /sys/kernel/debug/page_owner 文件存在时则 page_owner 已经开启)

步骤三:分析 page_owner 产生的记录

3.1 导出 page_owner 产生的记录

# cat /sys/kernel/debug/page_owner > page_owner_full.txt

(补充:这里以将 page_owner 产生的记录导出到名为 page_owner_full.txt 文件为例)


注意:
1) 此命令会产生体积很巨大的文件
2) 此命令会持续执行直到手动取消
3) 可以通过同时按下 “ctrl” 键和 “C” 键或者使用 kill 命令取消
4) 如果内存变化较快则可以让此命令多执行一会,反之则可以少执行一会

3.2 解析 page_owner 产生的记录

# page_owner_sort page_owner_full.txt sorted_page_owner.txt
loaded 42903
sorting ....
culling

(补充:这里以分析名为 page_owner_full.txt 的文件并将分析结果导入到 sorted_page_owner.txt 文件为例)

3.3 查看 page_owner 产生的记录

# less sorted_page_owner.txt
1 times:
Page allocated via order 0, mask 0x0(), pid 1, tgid 1 (swapper/0), ts 48952109 ns, free_ts 0 ns
PFN 4096 type Unmovable Block 8 type Unmovable Flags 0xfffffc0000100(slab|node=0|zone=1|lastcpupid=0x1fffff)
 register_early_stack+0x28/0x60
 init_page_owner+0x30/0x2d0
 kernel_init_freeable+0x13c/0x232
 kernel_init+0xa/0x108

1 times:
Page allocated via order 0, mask 0x0(), pid 1, tgid 1 (swapper/0), ts 48952566 ns, free_ts 0 ns
PFN 4097 type Unmovable Block 8 type Unmovable Flags 0xfffffc0000100(slab|node=0|zone=1|lastcpupid=0x1fffff)
 register_early_stack+0x28/0x60
 init_page_owner+0x30/0x2d0
 kernel_init_freeable+0x13c/0x232
 kernel_init+0xa/0x108
......

(补充:这里以查看名为 sorted_page_owner.txt 文件里的分析结果为例)

步骤四:关闭 page_owner

4.1 开启 page_owner

# grubby --remove-args="page_owner=on" --update-kernel=0

(注意:关闭 page_owner 会额外释放一定量的内存)

4.2 重启系统

# reboot

4.3 确认 page_owner 已关闭

4.3.1 通过 dmesg 命令确认 page_owner 是否关闭
# dmesg | grep page_owner
[    2.022585] page_owner is disabled

(补充:当显示此类信息时则 page_owner 没有开启)

4.3.2 通过 /sys/kernel/debug/ 目录确认 page_ownerr 是否关闭
# ls -l /sys/kernel/debug/page_owner
ls: cannot access '/sys/kernel/debug/page_owner': No such file or directory

(补充:当 /sys/kernel/debug/page_owner 文件不存在时则 page_owner 没有开启)

参考文献:

https://access.redhat.com/solutions/5609521

[排错] SLES 12 运行 yast lan 命令时,报错 “Details: Augeas parsing/serializing error: Iterated lens matched less than it should at /usr/share/augeas/lenses/dist/hosts.aug:23.12-.42:”

报错代码

Details: Augeas parsing/serializing error: Iterated lens matched less than it should at /usr/share/augeas/lenses/dist/hosts.aug:23.12-.42:

分析

/etc/hosts 文件中最后 1 行没有以 “\n” 结尾

解决方法

# echo >> /etc/hosts

参考文献

https://www.suse.com/zh-cn/support/kb/doc/?id=000019057