多个 udevd 进程导致平均负载升高

Issue

• 运行 udevadm trigger 时 CPU 负载高 ，存储堆栈会受到影响。

• 在运行 udevadm trigger 时，pvs 命令返回较长延迟，数据库受到影响(/etc/udev/rules.d/99-udev-oracle.rules 内容)：

  SUBSYSTEM=="block",KERNEL=="emcpower*",PROGRAM=="/lib/udev/scsi_id -gu /dev/%P",RESULT=="360000960000597000004512030521234",OWNER="grid",GROUP="dba",MODE="0660"
  SUBSYSTEM=="block",KERNEL=="emcpower*",PROGRAM=="/lib/udev/scsi_id -gu /dev/%P",RESULT=="36000096000059700000452103062543",OWNER="grid",GROUP="dba",MODE="0660"
  [...]
  

• 在运行 udevadm trigger 时，系统日志中会记录大量如下输出：

  Jan 14 11:12:13 localhost udevd[5913]: worker [34311] unexpectedly returned with status 0x0100
  Jan 14 11:12:13 localhost udevd[5913]: worker [34311] failed while handling '/devices/virtual/block/emcpowerx/emcpowerx1'
  Jan 14 11:12:13 localhost udevd[5913]: worker [34318] unexpectedly returned with status 0x0100
  Jan 14 11:12:13 localhost udevd[5913]: worker [34318] failed while handling '/devices/virtual/block/emcpowery/emcpowery1'
  Jan 14 11:12:13 localhost udevd[5913]: worker [34322] unexpectedly returned with status 0x0100
  Jan 14 11:12:13 localhost udevd[5913]: worker [34322] failed while handling '/devices/virtual/block/emcpowere/emcpowere1'
  Jan 14 11:12:14 localhost udevd[5913]: worker [34328] unexpectedly returned with status 0x0100
  Jan 14 11:12:14 localhost udevd[5913]: worker [34328] failed while handling '/devices/virtual/block/emcpowerf/emcpowerf1'
  

• 有许多 /sbin/udev -d 进程正在运行。

• 我抽查了几台其他 Oracle 服务器，发现通常有 1 到 3 个 udev 进程在运行。