Date: Tue, 4 Apr 2017 15:07:03 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Rik van Riel <riel@redhat.com>, Mel Gorman <mgorman@suse.de>,
        Michal Hocko <mhocko@suse.com>,
        Vladimir Davydov <vdavydov.dev@gmail.com>, linux-mm@kvack.org,
        cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
        kernel-team@fb.com
Subject: Re: [PATCH] mm: vmscan: fix IO/refault regression in cache
 workingset transition
Message-Id: <20170404150703.742c49d73921df6369ed3dbd@linux-foundation.org>
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On Tue,  4 Apr 2017 18:00:52 -0400 Johannes Weiner <hannes@cmpxchg.org> wrote:

> Since 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list")
> we noticed bigger IO spikes during changes in cache access patterns.
> 
> The patch in question shrunk the inactive list size to leave more room
> for the current workingset in the presence of streaming IO. However,
> workingset transitions that previously happened on the inactive list
> are now pushed out of memory and incur more refaults to complete.
> 
> This patch disables active list protection when refaults are being
> observed. This accelerates workingset transitions, and allows more of
> the new set to establish itself from memory, without eating into the
> ability to protect the established workingset during stable periods.
> 
> Fixes: 59dc76b0d4df ("mm: vmscan: reduce size of inactive file list")
> Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> Cc: <stable@vger.kernel.org> # 4.7+

That's a pretty large patch and the problem has been there for a year. 
I'm not sure that it's 4.11 material, let alone -stable.  Care to
explain further?