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Date: Fri, 28 Mar 2014 10:32:29 -0400
From: Rik van Riel <riel@redhat.com>
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Subject: Re: Adding compression before/above swapcache
References: <CALZtONDiOdYSSu02Eo78F4UL5OLTsk-9MR1hePc-XnSujRuvfw@mail.gmail.com> <20140327222605.GB16495@medulla.variantweb.net> <CALZtONDBNzL_S+UUxKgvNjEYu49eM5Fc2yJ37dJ8E+PEK+C7qg@mail.gmail.com>
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To: Dan Streetman <ddstreet@ieee.org>, Seth Jennings <sjennings@variantweb.net>
Cc: Hugh Dickins <hughd@google.com>, Mel Gorman <mgorman@suse.de>, Michal Hocko <mhocko@suse.cz>, Bob Liu <bob.liu@oracle.com>, Minchan Kim <minchan@kernel.org>, Johannes Weiner <hannes@cmpxchg.org>, Weijie Yang <weijie.yang@samsung.com>, Andrew Morton <akpm@linux-foundation.org>, Linux-MM <linux-mm@kvack.org>, linux-kernel <linux-kernel@vger.kernel.org>

On 03/28/2014 08:36 AM, Dan Streetman wrote:

> Well my general idea was to modify shrink_page_list() so that instead
> of calling add_to_swap() and then pageout(), anonymous pages would be
> added to a compressed cache.  I haven't worked out all the specific
> details, but I am initially thinking that the compressed cache could
> simply repurpose incoming pages to use as the compressed cache storage
> (using its own page mapping, similar to swap page mapping), and then
> add_to_swap() the storage pages when the compressed cache gets to a
> certain size.  Pages that don't compress well could just bypass the
> compressed cache, and get sent the current route directly to
> add_to_swap().

That sounds a lot like what zswap does. How is your
proposal different?

And, is there an easier way to implement that difference? :)


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