From: Roman Penyaev <roman.penyaev@profitbricks.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: Andy Lutomirski <luto@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Thomas Gleixner <tglx@linutronix.de>,
Ingo Molnar <mingo@redhat.com>, Tejun Heo <tj@kernel.org>,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc
Date: Tue, 25 Oct 2016 17:46:02 +0200 [thread overview]
Message-ID: <CAJrWOzDK3xt2unUTUZuVrfocvPPfXFtCKqvoxu1OKL76zcf-3w@mail.gmail.com> (raw)
In-Reply-To: <20161025140333.GB4326@redhat.com>
On Tue, Oct 25, 2016 at 4:03 PM, Oleg Nesterov <oleg@redhat.com> wrote:
> On 10/25, Roman Pen wrote:
>>
>> This patch avoids allocation of kthread structure on a stack, and simply
>> uses kmalloc.
>
> Oh. I didn't even read this patch, but I have to admit I personally do not
> like it. I can be wrong, but imo this is the step to the wrong direction.
it targets only one thing - we can't use stack anymore for keeping kthread
structure on it. so basically it is not even a step, just an attempt to
fix memory corruption after oops.
> struct kthread is already bloated, we should not bloat it more.
that is clear, but I wanted to keep code simpler with one allocation and
one structure for all the needs.
> Instead we should kill it. And to_kthread() too, at least in its current
> form.
that is nice and this is a step forward, but not with this patch.
>
> For example. parked/exited/cpu should go into smp_hotplug_thread. Yes,
> this needs cleanups.
>
> All we need is kthread_data() which returns the pointer to the private
> data used by kthread.
that means that we still need to store the private data inside task_struct
and probably again abuse some member.
>
> As for kthread_stop(), we no longer need to abuse ->vfork_done, we can
> use task_works:
yes, that can be done easily. in the current patch I already use the
task_work to free the kthread structure. but still for me is not clear
where to keep the private data if you have only task_struct in your
hands.
--
Roman
prev parent reply other threads:[~2016-10-25 15:46 UTC|newest]
Thread overview: 31+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-10-25 11:05 [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Roman Pen
2016-10-25 14:03 ` Oleg Nesterov
2016-10-25 15:43 ` Oleg Nesterov
2016-10-25 16:08 ` Roman Penyaev
2016-10-25 16:17 ` Oleg Nesterov
2016-10-25 16:52 ` Andy Lutomirski
2016-10-26 14:14 ` Oleg Nesterov
2016-10-26 14:57 ` Thomas Gleixner
2016-10-26 15:51 ` Oleg Nesterov
2016-10-26 18:31 ` Thomas Gleixner
2016-10-28 16:11 ` [PATCH 0/2] kthread: make struct kthread kmalloc'ed Oleg Nesterov
2016-10-28 16:11 ` [PATCH 1/2] " Oleg Nesterov
2016-10-28 18:48 ` Thomas Gleixner
2016-10-28 16:12 ` [PATCH 2/2] Revert "kthread: Pin the stack via try_get_task_stack()/put_task_stack() in to_live_kthread() function" Oleg Nesterov
2016-10-28 18:49 ` Thomas Gleixner
2016-10-28 18:44 ` [PATCH 0/2] kthread: make struct kthread kmalloc'ed Thomas Gleixner
2016-10-31 20:07 ` [PATCH 0/2] kthread: kill to_live_kthread() Oleg Nesterov
2016-10-31 20:07 ` [PATCH 1/2] kthread: don't use to_live_kthread() in kthread_stop() Oleg Nesterov
2016-11-09 7:58 ` Thomas Gleixner
2016-10-31 20:08 ` [PATCH 2/2] kthread: don't use to_live_kthread() in kthread_park() and kthread_unpark() Oleg Nesterov
2016-11-09 8:45 ` Thomas Gleixner
2016-11-09 17:27 ` Oleg Nesterov
2016-11-10 17:19 ` [PATCH 0/1] kthread: don't abuse kthread_create_on_cpu() in __kthread_create_worker() Oleg Nesterov
2016-11-10 17:20 ` [PATCH 1/1] " Oleg Nesterov
2016-11-14 11:12 ` Petr Mladek
2016-11-14 11:09 ` [PATCH 0/1] " Petr Mladek
2016-11-07 18:23 ` [PATCH 0/2] kthread: kill to_live_kthread() Andy Lutomirski
2016-10-26 16:13 ` [PATCH v3 1/1] kthread: allocate kthread structure using kmalloc Oleg Nesterov
2016-10-27 2:56 ` Josh Poimboeuf
2016-10-27 13:10 ` Oleg Nesterov
2016-10-25 15:46 ` Roman Penyaev [this message]
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