Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc

From	Oleg Nesterov <oleg@redhat.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc
Date	2016-10-25 18:20 +0200
Message-ID	<swcCe-7Zv-23@gated-at.bofh.it> (permalink)
References	<sw7Md-4N9-1@gated-at.bofh.it> <swaAq-6ET-17@gated-at.bofh.it> <swc9c-7vM-29@gated-at.bofh.it> <swcCe-7Zv-21@gated-at.bofh.it>
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Roman, I need to run away, just one note.

On 10/25, Roman Penyaev wrote:
>
> On Tue, Oct 25, 2016 at 5:43 PM, Oleg Nesterov <oleg@redhat.com> wrote:
>
> So in particular I do not understand this comment from the patch above
> where you abuse 'current->set_child_tid':
>
>  * This is the ugly but simple hack we will hopefully remove soon.
>
> how you are going to avoid this abuse of set_child_tid?

please ignore this comment. It actually reflects my desire to kill
struct kthread. If we won't do this, we can (ab)use this or another member
in task_struct.

> or vfork_done?
> because vfork_done is not only for waking up (yes, I totally agree, we
> can reuse task_work), it is also for getting a private data (like
> workqueue uses it):  task_struct->vfork_done->kthread->data.

kthreads simply should not use ->vfork_done at all. to_kthread() can
use the same pointer.

Oleg.

Thread

[PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Roman Pen <roman.penyaev@profitbricks.com> - 2016-10-25 13:10 +0200
  Re: [PATCH v3 1/1] kthread: allocate kthread structure using         kmalloc Oleg Nesterov <oleg@redhat.com> - 2016-10-25 16:10 +0200
    Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Roman Penyaev <roman.penyaev@profitbricks.com> - 2016-10-25 17:50 +0200
    Re: [PATCH v3 1/1] kthread: allocate kthread structure using         kmalloc Oleg Nesterov <oleg@redhat.com> - 2016-10-25 17:50 +0200
      Re: [PATCH v3 1/1] kthread: allocate kthread structure using         kmalloc Oleg Nesterov <oleg@redhat.com> - 2016-10-25 18:20 +0200
      Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Roman Penyaev <roman.penyaev@profitbricks.com> - 2016-10-25 18:20 +0200
      Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Andy Lutomirski <luto@amacapital.net> - 2016-10-25 19:00 +0200
        Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Oleg Nesterov <oleg@redhat.com> - 2016-10-26 16:20 +0200
          Re: [PATCH v3 1/1] kthread: allocate kthread structure using  kmalloc Thomas Gleixner <tglx@linutronix.de> - 2016-10-26 17:10 +0200
            Re: [PATCH v3 1/1] kthread: allocate kthread structure using         kmalloc Oleg Nesterov <oleg@redhat.com> - 2016-10-26 18:00 +0200
              Re: [PATCH v3 1/1] kthread: allocate kthread structure using  kmalloc Thomas Gleixner <tglx@linutronix.de> - 2016-10-26 20:40 +0200
          Re: [PATCH v3 1/1] kthread: allocate kthread structure using         kmalloc Oleg Nesterov <oleg@redhat.com> - 2016-10-26 18:20 +0200

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