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Date: Mon, 21 Mar 2016 13:30:17 -0700
From: Andrew Morton <akpm@linux-foundation.org>
To: Minchan Kim <minchan@kernel.org>
Cc: linux-kernel@vger.kernel.org,
        Sergey Senozhatsky <sergey.senozhatsky@gmail.com>, karam.lee@lge.com,
        sangseok.lee@lge.com, chan.jeong@lge.com
Subject: Re: [PATCH] zram: revive swap_slot_free_notify
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On Fri, 18 Mar 2016 16:58:31 +0900 Minchan Kim <minchan@kernel.org> wrote:

> <b430e9d1c6d4> "remove compressed copy from zram in-memory"
> applied swap_slot_free_notify call in *end_swap_bio_read* to
> remove duplicated memory between zram and memory.
> 
> However, with introducing rw_page in zram <8c7f01025f7b>
> "zram: implement rw_page operation of zram", it became void
> because rw_page doesn't need bio.
> 
> This patch restores the function for rw_page.

This is a bit mysterious.  What is the actual runtime effect of the
patch?  I assume that 8c7f01025f7b caused duplication of memory and
that the only problem is additional resource consumption?  If so, what
are the observable effects?  etcetera, please.