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Date:   Fri, 14 Aug 2020 21:14:59 -0700
From:   Andrew Morton <akpm@linux-foundation.org>
To:     Zhaoyang Huang <huangzhaoyang@gmail.com>,
        Roman Gushchin <klamm@yandex-team.ru>,
        Zhaoyang Huang <zhaoyang.huang@unisoc.com>, linux-mm@kvack.org,
        linux-kernel@vger.kernel.org
Subject: Re: [PATCH] mm : sync ra->ra_pages with bdi->ra_pages
Message-Id: <20200814211459.65f6db0211872e30684a630a@linux-foundation.org>
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        <20200814131034.f71a91c6827904e12a629e04@linux-foundation.org>
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On Fri, 14 Aug 2020 13:10:34 -0700 Andrew Morton <akpm@linux-foundation.org> wrote:

> On Fri, 14 Aug 2020 17:03:44 +0800 Zhaoyang Huang <huangzhaoyang@gmail.com> wrote:
> 
> > Some system(like android) will turbo read during startup via expanding the
> > readahead window and then set it back to normal(128kb as usual). However, some
> > files in the system process context will keep to be opened since it is opened
> > up and has no chance to sync with the updated value as it is almost impossible
> > to change the files attached to the inode(processes are unaware of these things)
> 
> How about making VM_READAHEAD_PAGES a variable?

Or make it settable in Kconfig?