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Date: Mon, 25 Nov 2013 16:57:29 -0800
From: Andrew Morton <akpm@linux-foundation.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Dave Chinner <david@fromorbit.com>, Rik van Riel <riel@redhat.com>,
        Jan Kara <jack@suse.cz>, Vlastimil Babka <vbabka@suse.cz>,
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        Roman Gushchin <klamm@yandex-team.ru>,
        Ozgun Erdogan <ozgun@citusdata.com>, Metin Doslu <metin@citusdata.com>,
        linux-mm@kvack.org, linux-fsdevel@vger.kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [patch 0/9] mm: thrash detection-based file cache sizing v6
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On Sun, 24 Nov 2013 18:38:19 -0500 Johannes Weiner <hannes@cmpxchg.org> wrote:

> This series solves the problem by maintaining a history of pages
> evicted from the inactive list, enabling the VM to detect frequently
> used pages regardless of inactive list size and facilitate working set
> transitions.

It's a very readable patchset - thanks for taking the time to do that.

> 31 files changed, 1253 insertions(+), 401 deletions(-)

It's also a *ton* of stuff.  More code complexity, larger kernel data
structures.  All to address a quite narrow class of workloads on a
relatively small window of machine sizes.  How on earth do we decide
whether it's worth doing?

Also, what's the memcg angle?  This is presently a global thing - do
you think we're likely to want to make it per-memcg in the future?