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From: "Huang\, Ying" <ying.huang@intel.com>
To: Michal Hocko <mhocko@kernel.org>, Minchan Kim <minchan@kernel.org>
Cc: "Huang\, Ying" <ying.huang@intel.com>,
        Andrew Morton <akpm@linux-foundation.org>, <linux-mm@kvack.org>,
        <linux-kernel@vger.kernel.org>, Johannes Weiner <hannes@cmpxchg.org>,
        "Rik van Riel" <riel@redhat.com>, Shaohua Li <shli@kernel.org>,
        Hugh Dickins <hughd@google.com>, Fengguang Wu <fengguang.wu@intel.com>,
        Tim Chen <tim.c.chen@intel.com>, Dave Hansen <dave.hansen@intel.com>
Subject: Re: [PATCH] mm, swap: Make VMA based swap readahead configurable
References: <20170921013310.31348-1-ying.huang@intel.com>
        <20170926132129.dbtr2mof35x4j4og@dhcp22.suse.cz>
Date: Wed, 27 Sep 2017 09:36:39 +0800
In-Reply-To: <20170926132129.dbtr2mof35x4j4og@dhcp22.suse.cz> (Michal Hocko's
        message of "Tue, 26 Sep 2017 15:21:29 +0200")
Message-ID: <87shf8c47s.fsf@yhuang-dev.intel.com>
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Michal Hocko <mhocko@kernel.org> writes:

> On Thu 21-09-17 09:33:10, Huang, Ying wrote:
>> From: Huang Ying <ying.huang@intel.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