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Subject: Re: [PATCH 00/21] mm: Preemptibility -v6
From: Peter Zijlstra <peterz@infradead.org>
To: Hugh Dickins <hughd@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
        Benjamin Herrenschmidt <benh@kernel.crashing.org>,
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Date: Mon, 24 Jan 2011 15:24:44 +0100
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On Mon, 2011-01-24 at 13:45 +0100, Peter Zijlstra wrote:
> The only significant loser, I think,
> > would be page reclaim (when concurrent with truncation): could spin for a
> > long time waiting for the i_mmap_mutex it expects would soon be dropped? 

Well it won't spin (much) but mostly go to sleep if it really takes very
long, but then, could it really take much longer than say a lock_page()
when reclaim hits a page under IO?