linux-kernel - Re: [RFC PATCH 0/2] workqueue: Introduce PF_WQ_RESCUE

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Date:   Thu, 3 Aug 2023 10:34:47 -1000
From:   Tejun Heo <tj@...nel.org>
To:     Aaron Tomlin <atomlin@...mlin.com>
Cc:     jiangshanlai@...il.com, linux-kernel@...r.kernel.org,
        peterz@...radead.org
Subject: Re: [RFC PATCH 0/2] workqueue: Introduce PF_WQ_RESCUE_WORKER

On Thu, Aug 03, 2023 at 09:19:14PM +0100, Aaron Tomlin wrote:
> > But why do you need to identify rescue workers? What are you trying to
> > achieve?
> 
> Hi Tejun,
> 
> I had a conversation with a colleague of mine. It can be useful to identify
> and account for all kernel threads. From the perspective of user-mode, the
> name given currently to the rescuer kworker is ambiguous. For instance,
> "kworker/u16:9-kcryptd/253:0" is clearly identifiable as an unbound kworker
> for the specified workqueue which can have their CPU affinity adjusted as

Note that the name changes to the work item the worker is currently
executing. It won't stay that way. Workers are shared across the workqueues,
so I'm not sure "identify and account all kernel threads" is working as well
as you think it is.

> you mentioned before. I think if we followed the same naming convention
> for a rescuer kworker then it would be more consistent. I'll send a patch
> so it can be discussed further.

We can certainly rename them to indicate that they are rescuers - e.g. maybe
krescuer? But, at the moment, the proposed reason seems rather dubious.

Thanks.

-- 
tejun