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From: Matthew Wilcox <willy@infradead.org>
To: Zhaoyang Huang <huangzhaoyang@gmail.com>
Cc: Roman Gushchin <klamm@yandex-team.ru>,
	Andrew Morton <akpm@linux-foundation.org>,
	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
Date: Fri, 14 Aug 2020 12:48:19 +0100	[thread overview]
Message-ID: <20200814114819.GW17456@casper.infradead.org> (raw)
In-Reply-To: <1597395824-3325-1-git-send-email-zhaoyang.huang@unisoc.com>

On Fri, Aug 14, 2020 at 05:03:44PM +0800, Zhaoyang Huang 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)

Hang on, you're saying that the _only_ way to do turbo-read is the way
that userspace currently does it, and userspace cannot be modified,
only the kernel?  I think somebody has their priorities wrong!

> We sync ra->ra_pages with bdi->ra_pages when read. Furthermore, in consideration
> of the scenario of eio and fadvise(...,POSIX_FADV_SEQUENTIAL).We introduce a
> seq_read_fact to record the factors of above two cases.

No, this is far too complicated.


  reply	other threads:[~2020-08-14 11:48 UTC|newest]

Thread overview: 8+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-08-14  9:03 [PATCH] mm : sync ra->ra_pages with bdi->ra_pages Zhaoyang Huang
2020-08-14 11:48 ` Matthew Wilcox [this message]
2020-08-14 20:10 ` Andrew Morton
2020-08-15  4:14   ` Andrew Morton
2020-08-17 10:59     ` Zhaoyang Huang
2020-08-17 10:59       ` Zhaoyang Huang
2020-08-19  6:54 ` Zhaoyang Huang
2020-08-19  6:54   ` Zhaoyang Huang

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