From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: freezing of kernel threads
Date: Tue, 27 Nov 2012 11:47:50 -0500
Message-ID: <20121127164750.GA27586@phenom.dumpdata.com>
References: <50AE18CA02000078000AA90F@nat28.tlf.novell.com>
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To: Jan Beulich <JBeulich@suse.com>
Cc: Keir Fraser <keir@xen.org>, xen-devel <xen-devel@lists.xen.org>
List-Id: xen-devel@lists.xenproject.org

On Thu, Nov 22, 2012 at 11:21:30AM +0000, Jan Beulich wrote:
> Keir,
> 
> in linux-2.6.18-xen.hg c/s 74:cb50d25a9468 you made blktap
> match blkback in calling try_to_freeze() from the main thread loop.
> Threads in other drivers didn't get changed, though. Is there a
> particular reason why only block, and only backend, threads are in
> need of this (the only other one using it is xenfb_thread())?
> 
> Konrad, as of 2.6.23 kernel threads are non-freezable by default,
> i.e. xen-blkback calling try_to_freeze() is completely pointless
> without a prior call to set_freezable(). Also, in case the latter is to
> be added, switching to wait_event_freezable() instead of the
> direct use of try_to_freeze() might be the right way to go.

OK, any idea why the need to be come freezable was added in? Just
for power suspend/resume?

> 
> Jan
>