linux-kernel - Re: [PATCH] mm, swap: Make VMA based swap readahead configurable

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Date:   Wed, 27 Sep 2017 09:36:39 +0800
From:   "Huang\, Ying" <ying.huang@...el.com>
To:     Michal Hocko <mhocko@...nel.org>, Minchan Kim <minchan@...nel.org>
Cc:     "Huang\, Ying" <ying.huang@...el.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        <linux-mm@...ck.org>, <linux-kernel@...r.kernel.org>,
        Johannes Weiner <hannes@...xchg.org>,
        "Rik van Riel" <riel@...hat.com>, Shaohua Li <shli@...nel.org>,
        Hugh Dickins <hughd@...gle.com>,
        Fengguang Wu <fengguang.wu@...el.com>,
        Tim Chen <tim.c.chen@...el.com>,
        Dave Hansen <dave.hansen@...el.com>
Subject: Re: [PATCH] mm, swap: Make VMA based swap readahead configurable

Michal Hocko <mhocko@...nel.org> writes:

> On Thu 21-09-17 09:33:10, Huang, Ying wrote:
>> From: Huang Ying <ying.huang@...el.com>
>> 
>> This patch adds a new Kconfig option VMA_SWAP_READAHEAD and wraps VMA
>> based swap readahead code inside #ifdef CONFIG_VMA_SWAP_READAHEAD/#endif.
>> This is more friendly for tiny kernels.
>
> How (much)?

OK.  I will measure it.

>> And as pointed to by Minchan
>> Kim, give people who want to disable the swap readahead an opportunity
>> to notice the changes to the swap readahead algorithm and the
>> corresponding knobs.
>
> Why would anyone want that?
>
> Please note that adding new config options make the already complicated
> config space even more problematic so there should be a good reason to
> add one. Please make sure your justification is clear on why this is
> worth the future maintenance and configurability burden.

Hi, Minchan,

Could you give more information on this?

Best Regards,
Huang, Ying