[Crash-utility] [Crash] [PATCH] add a new command: lscgroup

[Dave Anderson]

----- Original Message -----

> Hello, Dave,
> 
> To begin with, I am sincerely grateful for your detailed suggestions.
> I have read the suggetions you gave and finished modifying the relative
> parts. The following will demonstrate the modifications.
> 
> The first is when it comes to older kernels that do not have cgroups, it
> now offers justification of whether the kernel have cgroups and output
> information when the kernel do not contain cgroup.

Good...
 
> Secondly, you mentioned the cgroups "unabled" in the previous mail,
> considerring those inactive cgroups whose root(cgroupfs_root) is not
> linked by the active root list, I prefer to display something when there
> are no active cgroups other than output the inactive cgroups.
> If the inactive cgroups' information is needy, I need to rethink and
> find another way to get target data structure.

Showing just the enabled cgroups is fine, and what you have done is OK.
 
> Thirdly, the unnecessary -h option was deleted and help information was
> corrected according to your suggestions.

OK.
 
> Lastly, the changed "lscgroup" command add the address of cgroup when
> displaying cgroups. For the reason that address length is fixed on a
> certain system, the first column of output is used to display the address.

Typically command headers use capitalized structure names,
and output sections are separated with two spaces.  So instead
of this:

 crash> lscgroup
   CGROUP_ADDR            <CONTROLLER>:<PATH>
 ffff88020ff82030        perf_event:/
 ffff88020ff80030        blkio:/
 ffff8801f5f2d400        blkio:/libvirt
 ffff880212ae2c00        blkio:/libvirt/lxc
 ffff8801f659d000        blkio:/libvirt/qemu
 
I would suggest this:
 
 crash> lscgroup
      CGROUP       CONTROLLER:PATH
 ffff88020ff82030  perf_event:/
 ffff88020ff80030  blkio:/
 ffff8801f5f2d400  blkio:/libvirt
 ffff880212ae2c00  blkio:/libvirt/lxc
 ffff8801f659d000  blkio:/libvirt/qemu
 ...

And I would suggest a new option, where a user can enter a cgroup
address, and it would find and display its controller/path name:

 crash> lscgroup
      CGROUP       CONTROLLER:PATH
 ffff8801f668c400  cpuacct,cpu:/system/nfs-lock.service
 crash>

Thanks,
  Dave