Re: [PATCH] mdadm/systemd: change KillMode from none to mixed in service files

[Coly Li <colyli@suse.de>]

On 12/2/21 5:51 AM, NeilBrown wrote:
> On Thu, 02 Dec 2021, Coly Li wrote:
>> On 12/2/21 12:28 AM, Benjamin Brunner wrote:
>>> Hi all,
>>>
>>> On 01.12.21 17:23, Coly Li wrote:
>>>> On 12/2/21 12:08 AM, mtkaczyk wrote:
>>>>> Hi Coly,
>>>>>
>>>>>> This patch changes KillMode in above listed service files from "none"
>>>>>> to "mixed", to follow systemd recommendation and avoid potential
>>>>>> unnecessary issue.
>>>>> What about mdmonitor.service? Should we add it there too? Now it is not
>>>>> defined.
>>>> It was overlooked when I did grep KillMode. Yes, I agree
>>>> mdmonitor.service should have a KillMode key word as well.
>>>>
>>>> Let me post a v2 version.
>>>>
>>> JFYI, when KillMode is not set, it defaults to KillMode=control-group,
>>> see https://www.freedesktop.org/software/systemd/man/systemd.kill.html.
>>>
>>> Therefore, it shouldn't be necessary to explicitly add it (as long as
>>> control-group is working in case of mdmonitor.service, of course).
>> Hi Benjamin,
>>
>> Please correct me if I am wrong, I see the difference of the KillMode is,
>> -- KillMode=mixed stops the processes more gentally, it kill the main
>> process with SIGTERM and the remaining processes with SIGKILL.
>> -- KillMode=control-group kills all in-cgroup processes with SIGKILL,
>> which I feel a bit cruel for the main process.
> There is no point sending SIGTERM to a process which doesn't respond to
> it.  mdmon is the only mdadm service which handles SIGTERM.  So it might
> make sense to uise KillMode=mixed for that.
> For anything else, SIGKILL via KillMode=control-group is perfectly
> acceptable.

Hi Neil,

Thanks for the hint. So it seems remove the KillMode= lines from the 
systemd files might be best choice.

Hi Benjamin,

How do you think about removing the KillMode= lines to use SIGKILL as 
default action ?

Thanks.

Coly Li