linux-kernel - Re: [RFC 0/2] Add interface let ZRAM close swap cache

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Message-ID: <20161128144917.GQ14788@dhcp22.suse.cz>
Date:   Mon, 28 Nov 2016 15:49:17 +0100
From:   Michal Hocko <mhocko@...nel.org>
To:     Hui Zhu <zhuhui@...omi.com>
Cc:     minchan@...nel.org, ngupta@...are.org,
        sergey.senozhatsky.work@...il.com, dan.j.williams@...el.com,
        jthumshirn@...e.de, akpm@...ux-foundation.org, re.emese@...il.com,
        andriy.shevchenko@...ux.intel.com, vishal.l.verma@...el.com,
        hannes@...xchg.org, mgorman@...hsingularity.net, vbabka@...e.cz,
        vdavydov.dev@...il.com, kirill.shutemov@...ux.intel.com,
        ying.huang@...el.com, yang.shi@...aro.org,
        dave.hansen@...ux.intel.com, willy@...ux.intel.com,
        vkuznets@...hat.com, vitalywool@...il.com, jmarchan@...hat.com,
        lstoakes@...il.com, geliangtang@....com, viro@...iv.linux.org.uk,
        hughd@...gle.com, riel@...hat.com, linux-kernel@...r.kernel.org,
        linux-mm@...ck.org, teawater@...il.com
Subject: Re: [RFC 0/2] Add interface let ZRAM close swap cache

On Fri 25-11-16 16:25:11, Hui Zhu wrote:
> SWAP will keep before swap cache before swap space get full.  It will
> make swap space cannot be freed.  It is harmful to the system that use
> ZRAM because its space use memory too.

I have hard time to follow what you are trying to say here. Could you be
more specific about what is the actual problem?

> This two patches will add a sysfs switch to ZRAM that open or close swap
> cache without check the swap space.

I find this a crude hack to be honest. Please make sure to describe why
the swap cache stays in the way and why this is not problem in other
setups.
-- 
Michal Hocko
SUSE Labs