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From: Nick Piggin <nickpiggin@yahoo.com.au>
To: Hans Reiser <reiser@namesys.com>
Cc: Alan Cox <alan@lxorguk.ukuu.org.uk>,
	thenewme91@gmail.com, Christoph Hellwig <hch@infradead.org>,
	Denis Vlasenko <vda@ilport.com.ua>,
	chriswhite@gentoo.org, LKML <linux-kernel@vger.kernel.org>,
	ReiserFS List <reiserfs-list@namesys.com>
Subject: Re: I request inclusion of reiser4 in the mainline kernel
Date: Tue, 20 Sep 2005 14:16:30 +1000	[thread overview]
Message-ID: <432F8D1E.7060300@yahoo.com.au> (raw)
In-Reply-To: <432E4786.7010001@namesys.com>

Hans Reiser wrote:

>So why is the code in the kernel so hard to read then?
>
>Linux kernel code is getting better, and Andrew Morton's code is
>especially good, but for the most part it's unnecessarily hard to read. 
>Look at the elevator code for instance.  Ugh.
>
>

What's wrong with the elevator code?

The elevator code was one of the first things I got involved with
as a complete kernel newbie, and I was able to follow the current
code well enough to make a new IO scheduler, and extend the
elevator API sufficiently to provide the fairly unique
capabilities I needed.

If it is the elevator *API* you are worried about, that is fairly
trivial and well documented by Jens and myself in
Documentation/block/biodoc.txt, along with an overview of some key
ideas useful for iosched implementors.

as-iosched.c itself is IMO reasonably well commented (at least
the non-trivial, non-boilerplate functions). That is not to say it
is trivial to understand because it is a fairly complex state
machine and heuristics, but at less than 2000 lines of very well
contained code it is not an impossible task to understand it.

If that is too much for you, noop-iosched.c implements a fully
working io scheduler in exactly 94 lines, including whitespace and
comments.

What are your specific concerns? I would be interested in helping
to fix any valid ones you have.

Thanks,
Nick


Send instant messages to your online friends http://au.messenger.yahoo.com 

  parent reply	other threads:[~2005-09-20  4:16 UTC|newest]

Thread overview: 143+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2005-09-16 17:05 I request inclusion of reiser4 in the mainline kernel Hans Reiser
2005-09-16 17:15 ` Christoph Hellwig
2005-09-16 17:40 ` Christoph Hellwig
2005-09-16 19:39   ` Hans Reiser
2005-09-16 19:52     ` Kyle Moffett
2005-09-17 10:51       ` Denis Vlasenko
2005-09-19  5:01         ` Hans Reiser
2005-09-16 20:50     ` Lennart Sorensen
2005-09-16 20:53       ` Lennart Sorensen
2005-09-19  5:09         ` Hans Reiser
2005-09-17  9:22     ` Christoph Hellwig
2005-09-17 10:56       ` Denis Vlasenko
2005-09-17 11:15         ` Denis Vlasenko
2005-09-18  0:34           ` Chris White
2005-09-18 10:21             ` Denis Vlasenko
2005-09-18 10:26               ` Christoph Hellwig
     [not found]                 ` <200509181406.25922.chrivers@iversen-net.dk>
2005-09-18 12:32                   ` Denis Vlasenko
2005-09-18 18:25                     ` David Masover
2005-09-19  5:16                   ` Hans Reiser
2005-09-19  5:56                     ` Valdis.Kletnieks
2005-09-19  6:53                       ` Hans Reiser
2005-09-18 17:22                 ` michael chang
2005-09-18 19:16                   ` Valdis.Kletnieks
2005-09-18 20:04                   ` Horst von Brand
2005-09-18 20:29                     ` David Masover
2005-09-18 21:43                       ` Dan Oglesby
2005-09-19  1:37                         ` PFC
2005-09-19  1:53                           ` Kyle Moffett
2005-09-19  2:48                             ` Dr.Dre
2005-09-19  4:37                           ` Marc Perkel
2005-09-18 20:33                     ` Marc Perkel
2005-09-19  5:44                     ` Hans Reiser
2005-09-19 10:39                       ` Nikita Danilov
2005-09-19 18:51                         ` Hans Reiser
2005-09-19 10:51                       ` Alan Cox
2005-09-19 23:03                       ` Horst von Brand
2005-09-20  8:00                         ` Hans Reiser
2005-09-20  7:51                       ` Pavel Machek
2005-09-20 14:41                         ` David Masover
2005-09-20 17:25                           ` Hans Reiser
2005-09-20 18:17                           ` Horst von Brand
     [not found]                           ` <20050920175727.GA17820@thunk.org>
     [not found]                             ` <1127240326.10407.22.camel@localhost>
2005-09-20 21:11                               ` Theodore Ts'o
2005-09-21  0:08                                 ` Hans Reiser
2005-09-21  9:05                                 ` Vitaly Fertman
2005-09-20 17:46                         ` Hans Reiser
     [not found]                         ` <200509202328.28501.rik@osrc.info>
2005-09-20 20:15                           ` Valdis.Kletnieks
2005-09-20 21:17                             ` Theodore Ts'o
2005-09-20 21:33                               ` Valdis.Kletnieks
2005-09-20 21:37                           ` Pavel Machek
     [not found]                             ` <200509210133.41710.rik@osrc.info>
2005-09-20 22:10                               ` Pavel Machek
2005-09-21  0:22                                 ` Hans Reiser
2005-09-21  0:04                         ` Theodore Ts'o
2005-09-21  0:13                           ` Hans Reiser
2005-09-21  0:27                           ` Ric Wheeler
2005-09-21  0:44                             ` Hans Reiser
2005-09-21  1:12                               ` Ric Wheeler
2005-09-21  3:05                                 ` Hans Reiser
2005-09-21  4:55                                   ` Gregory Maxwell
2005-09-21 11:21                                     ` Ric Wheeler
2005-09-21 17:36                                       ` Hans Reiser
2005-09-21 18:12                                         ` Ric Wheeler
2005-09-21 10:16                                   ` Vitaly Fertman
2005-09-21  1:01                           ` Gregory Maxwell
2005-09-21  1:15                             ` Ric Wheeler
2005-09-23  6:21                             ` David Greaves
2005-09-23 11:37                               ` Gregory Maxwell
2005-09-18 20:52                   ` Kyle Moffett
2005-09-19  0:56                     ` michael chang
2005-09-18 21:38                   ` Alan Cox
2005-09-19  5:07                     ` Hans Reiser
2005-09-19  9:01                       ` Christoph Hellwig
2005-09-19  9:16                         ` Christoph Hellwig
2005-09-19  9:21                         ` Andrew Morton
2005-09-19 10:43                       ` Alan Cox
2005-09-19 18:50                         ` Hans Reiser
2005-09-19 18:51                         ` Hans Reiser
2005-09-19 12:45                       ` Jens Axboe
2005-09-20  4:16                       ` Nick Piggin [this message]
2005-09-20  6:28                         ` Hans Reiser
2005-09-20  7:16                           ` Nick Piggin
2005-09-20  7:59                             ` Hans Reiser
2005-09-20  8:31                               ` elevators (was Re: I request inclusion of reiser4 in the mainline kernel) Nick Piggin
2005-09-20 17:18                                 ` Hans Reiser
2005-09-20 11:42                               ` I request inclusion of reiser4 in the mainline kernel Jens Axboe
2005-09-20 13:30                                 ` Lorenzo Allegrucci
2005-09-20 13:41                                   ` Jens Axboe
2005-09-20 13:55                                   ` Nikita Danilov
2005-09-20 17:46                                     ` Hans Reiser
2005-09-20 15:25                                   ` Randy.Dunlap
2005-09-20 17:21                                 ` Hans Reiser
2005-09-20 18:18                                   ` Jens Axboe
2005-09-20 15:42                           ` Horst von Brand
2005-09-20 17:46                             ` Hans Reiser
2005-09-20 18:25                               ` Jens Axboe
2005-09-20 18:27                               ` Nikita Danilov
2005-09-21 21:16                                 ` Hans Reiser
2005-09-21 21:37                                   ` Nikita Danilov
2005-09-21 22:07                                     ` Hans Reiser
2005-09-20 17:55                             ` Hans Reiser
2005-09-19 20:00               ` Bill Davidsen
2005-09-19 21:55                 ` Hans Reiser
2005-09-18 10:23         ` Christoph Hellwig
2005-09-18 18:10           ` David Masover
2005-09-19 20:41   ` Alexander Zarochentsev
2005-09-26 15:03   ` Vladimir V. Saveliev
2005-10-04 19:00     ` Christoph Hellwig
2005-10-04 21:10       ` Hans Reiser
2005-11-11 16:15   ` Vladimir V. Saveliev
2006-01-09  9:54   ` What's the state of Reiser4 inclusion " Giovanni A. Orlando
2006-01-09  9:15     ` Arjan van de Ven
2005-09-17 11:16 ` I request inclusion of reiser4 " Denis Vlasenko
2005-09-18  3:06   ` George Garvey
2005-09-18 10:02   ` Nikita Danilov
2005-09-19 19:36     ` Stephen Pollei
2005-09-19 21:10       ` Nikita Danilov
2005-09-19 21:47         ` Benjamin Herrenschmidt
2005-09-19 22:01         ` Hans Reiser
2005-09-19 23:15     ` Horst von Brand
2005-09-20  3:57       ` Stephen Pollei
2005-09-20  9:30         ` Nikita Danilov
2005-09-20 15:36           ` Horst von Brand
2005-09-20 17:43             ` Hans Reiser
2005-09-20 18:36               ` Horst von Brand
2005-09-20 22:08               ` Stephen Pollei
2005-09-21  0:21                 ` Hans Reiser
2005-09-21 10:47                   ` Nikita Danilov
2005-09-21 17:34                     ` Hans Reiser
2005-09-21 18:31                       ` Nikita Danilov
2005-09-21 18:39                         ` Hans Reiser
2005-09-20 17:53         ` Alexandre Oliva
2005-09-20 22:57           ` Stephen Pollei
2005-09-21  8:15             ` Alexandre Oliva
2005-09-18 22:12   ` Hans Reiser
2005-09-18 11:06 ` Christoph Hellwig
2005-09-19  9:18   ` Vladimir V. Saveliev
2005-09-19  9:24     ` Christoph Hellwig
     [not found]       ` <43302CF7.2010901@namesys.com>
     [not found]         ` <20050920154711.GA6698@infradead.org>
2005-09-30 12:10           ` Vladimir V. Saveliev
2005-09-30 17:27             ` Nikita Danilov
2005-10-04 18:12             ` Christoph Hellwig
2005-09-19  9:40     ` Alexey Dobriyan
2005-09-20 22:40 James Lamanna
2005-09-20 23:46 ` Vadim Lobanov
2005-09-20 23:51   ` James Lamanna

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