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Subject: Re: [PATCH] slow_work_thread() should do the exclusive wait
From: Trond Myklebust <Trond.Myklebust@netapp.com>
To: Oleg Nesterov <oleg@redhat.com>
Cc: David Howells <dhowells@redhat.com>,
       Andrew Morton <akpm@linux-foundation.org>,
       Serge Hallyn <serue@us.ibm.com>, Steve Dickson <steved@redhat.com>,
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       Daire Byrne <Daire.Byrne@framestore.com>, linux-kernel@vger.kernel.org
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Date: Mon, 13 Apr 2009 17:57:21 -0400
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On Mon, 2009-04-13 at 23:48 +0200, Oleg Nesterov wrote:
> On 04/13, David Howells wrote:
> >
> > Trond Myklebust <Trond.Myklebust@netapp.com> wrote:
> >
> > > Should that really be TASK_INTERRUPTIBLE? I don't see anything obvious
> > > in the enclosing for(;;) loop that checks for or handles signals...
> >
> > If it were TASK_UNINTERRUPTIBLE, it would sit there in the D-state when not
> > doing anything.  I must admit, I thought I was calling daemonize(), but that
> > seems to have got lost somewhere.
> 
> daemonize() is not needed, kthread_create() creates the kernel thread which
> ignores all signals. So it doesn't matter which state we use to sleep,
> TASK_INTERRUPTIBLE or TASK_UNINTERRUPTIBLE.

Yes, but that is precisely why it is cleaner to use
TASK_UNINTERRUPTIBLE. It documents the fact that signal handling isn't
needed (whether or not the thread is blocking them).

Trond
-- 
Trond Myklebust
Linux NFS client maintainer

NetApp
Trond.Myklebust@netapp.com
www.netapp.com