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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Fri, 5 May 2023 18:53:33 -0700
Message-ID: <CAHk-=wifMNUnnuqXWjuSq2jM3VOKmKNjyW9FAsi3aEtV5PFcVg@mail.gmail.com>
Subject: Re: [PATCH v11 8/8] vhost: use vhost_tasks for worker threads
To:     Mike Christie <michael.christie@oracle.com>
Cc:     nicolas.dichtel@6wind.com, Christian Brauner <brauner@kernel.org>,
        hch@infradead.org, stefanha@redhat.com, jasowang@redhat.com,
        mst@redhat.com, sgarzare@redhat.com,
        virtualization@lists.linux-foundation.org, ebiederm@xmission.com,
        konrad.wilk@oracle.com, linux-kernel@vger.kernel.org
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On Fri, May 5, 2023 at 3:38=E2=80=AFPM Mike Christie
<michael.christie@oracle.com> wrote:
>
> If it's ok to change the behavior of "ps -u root", then we can do this pa=
tch:

I think this is the right thing to do.

Making the user worker threads show up as threads with the vhost
process as the parent really seems like a much better model, and more
accurate.

Yes, they used to show up as random kernel threads, and you'd see them
as such (not just for "ps -u root", but simply also with just a normal
"ps ax" kind of thing). But that isn't all that helpful, and it's
really just annoying to see our kernel threads in "ps ax" output, and
I've often wished we didn't do that (it think of all the random
"kworker/xyz-kcryptd" etc things that show up).

So I think showing them as the threaded children of the vhost process
is much nicer, and probably the best option.

Because I don't thin kanything is going to get the *old* behavior of
showing them as the '[vhost-xyz]' system threads (or whatever the old
output ended up being in 'ps ax'), but hopefully nothing wants that
horror anyway.

At a minimum, the parenting is fundamentally going to look different
in the new model.

                   Linus