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Date: Fri, 2 Mar 2012 11:57:00 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Fengguang Wu <fengguang.wu@intel.com>
Cc: Jan Kara <jack@suse.cz>, Greg Thelen <gthelen@google.com>,
        Ying Han <yinghan@google.com>,
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        Minchan Kim <minchan.kim@gmail.com>,
        Linux Memory Management List <linux-mm@kvack.org>,
        LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 5/9] writeback: introduce the pageout work
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On Fri, 2 Mar 2012 18:39:51 +0800
Fengguang Wu <fengguang.wu@intel.com> wrote:

> > And I agree it's unlikely but given enough time and people, I
> > believe someone finds a way to (inadvertedly) trigger this.
> 
> Right. The pageout works could add lots more iput() to the flusher
> and turn some hidden statistical impossible bugs into real ones.
> 
> Fortunately the "flusher deadlocks itself" case is easy to detect and
> prevent as illustrated in another email.

It would be a heck of a lot safer and saner to avoid the iput().  We
know how to do this, so why not do it?