linux-kernel - Re: [PATCH] zram: revive swap_slot_free

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Message-Id: <20160321133017.1e925cc45cdc9153d2623ef8@linux-foundation.org>
Date:	Mon, 21 Mar 2016 13:30:17 -0700
From:	Andrew Morton <akpm@...ux-foundation.org>
To:	Minchan Kim <minchan@...nel.org>
Cc:	linux-kernel@...r.kernel.org,
	Sergey Senozhatsky <sergey.senozhatsky@...il.com>,
	karam.lee@....com, sangseok.lee@....com, chan.jeong@....com
Subject: Re: [PATCH] zram: revive swap_slot_free_notify

On Fri, 18 Mar 2016 16:58:31 +0900 Minchan Kim <minchan@...nel.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.