From: Davide Libenzi <davidel@xmailserver.org>
To: Rusty Russell <rusty@rustcorp.com.au>
Cc: Linus Torvalds <torvalds@osdl.org>, Andrew Morton <akpm@osdl.org>,
<mingo@redhat.com>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 1/2] kthread_create
Date: Sat, 3 Jan 2004 20:55:57 -0800 (PST) [thread overview]
Message-ID: <Pine.LNX.4.44.0401032054490.2022-100000@bigblue.dev.mdolabs.com> (raw)
In-Reply-To: <Pine.LNX.4.44.0401032039350.2022-100000@bigblue.dev.mdolabs.com>
On Sat, 3 Jan 2004, Davide Libenzi wrote:
> On Sun, 4 Jan 2004, Rusty Russell wrote:
>
> > In message <Pine.LNX.4.44.0401031021280.1678-100000@bigblue.dev.mdolabs.com> you write:
> > > Rusty, I took a better look at the patch and I think we can have
> > > per-kthread stuff w/out littering the task_struct and by making the thing
> > > more robust.
> >
> > Except sharing data with a lock is perfectly robust.
> >
> > > We keep a global list_head protected by a global spinlock. We
> > > define a structure that contain all the per-kthread stuff we need
> > > (including a task_struct* to the kthread itself). When a kthread starts it
> > > will add itself to the list, and when it will die it will remove itself
> > > from the list.
> >
> > Yeah, I deliberately didn't implement this, because (1) it seems like
> > a lot of complexity when using a lock and letting them share a single
> > structure works fine and is even simpler, and (2) the thread can't
> > just "do_exit()".
> >
> > You can get around (2) by having a permenant parent "kthread" thread
> > which is a parent to all the kthreads (it'll get a SIGCHLD when
> > someone does "do_exit()"). But the implementation was pretty ugly,
> > since it involved having a communications mechanism with the kthread
> > parent, which means you have the global ktm_message-like-thing for
> > this...
>
> You will lose in any case. What happens if the thread does do_exit() and
> you do kthread_stop() after that?
> With the patch I posted to you, the kthread_stop() will simply miss the
> lookup and return -ENOENT.
Nope, we are screwed in any case. Is it really important to give the
ability to do do_exit() for kthreads? I mean, why a simple return would
not work?
- Davide
next prev parent reply other threads:[~2004-01-04 4:55 UTC|newest]
Thread overview: 47+ messages / expand[flat|nested] mbox.gz Atom feed top
2003-12-31 3:31 [PATCH 1/2] kthread_create Rusty Russell
2003-12-31 4:33 ` Jeff Garzik
2003-12-31 5:28 ` Rusty Russell
2003-12-31 6:34 ` Jeff Garzik
2003-12-31 8:47 ` Benjamin Herrenschmidt
2004-01-01 23:51 ` Rusty Russell
2003-12-31 4:49 ` Andrew Morton
2003-12-31 5:18 ` Rusty Russell
2003-12-31 5:06 ` Davide Libenzi
2003-12-31 5:34 ` Rusty Russell
2003-12-31 5:56 ` Davide Libenzi
2003-12-31 6:27 ` Rusty Russell
2004-01-01 3:45 ` Davide Libenzi
2004-01-02 7:09 ` Rusty Russell
2004-01-02 16:58 ` Davide Libenzi
2004-01-03 3:05 ` Rusty Russell
2004-01-03 3:43 ` Davide Libenzi
2004-01-03 11:47 ` Rusty Russell
2004-01-04 4:23 ` Davide Libenzi
2004-03-29 15:42 ` Davide Libenzi
2004-01-03 19:00 ` Davide Libenzi
2004-01-03 23:53 ` Davide Libenzi
2004-01-04 2:34 ` Rusty Russell
2004-01-04 4:42 ` Davide Libenzi
2004-01-04 4:55 ` Davide Libenzi [this message]
2004-01-04 9:35 ` Rusty Russell
2004-01-04 23:03 ` Davide Libenzi
2004-01-05 4:09 ` Rusty Russell
2004-01-05 5:06 ` Davide Libenzi
2004-01-05 6:38 ` Rusty Russell
2004-01-05 6:52 ` Davide Libenzi
2004-01-07 7:00 ` Rusty Russell
2004-01-07 7:25 ` Davide Libenzi
2004-01-08 0:33 ` Rusty Russell
2004-03-29 15:42 ` Davide Libenzi
2004-03-29 15:42 ` Davide Libenzi
2004-03-29 15:41 ` Davide Libenzi
2004-03-29 15:42 ` Rusty Russell
2004-03-29 15:40 ` Davide Libenzi
2004-03-29 15:41 ` Rusty Russell
2004-03-29 15:39 ` Davide Libenzi
2004-03-29 15:39 ` Rusty Russell
2004-03-29 15:38 ` Davide Libenzi
2003-12-31 6:31 ` Srivatsa Vaddagiri
2003-12-31 7:12 ` Davide Libenzi
2003-12-31 23:25 ` Rusty Russell
2003-12-31 18:02 Albert Cahalan
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