| Linus Torvalds | 1da177e | 2005-04-16 15:20:36 -0700 | [diff] [blame] | 1 | Documentation for /proc/sys/		kernel version 2.2.10 | 
 | 2 | 	(c) 1998, 1999,  Rik van Riel <riel@nl.linux.org> | 
 | 3 |  | 
 | 4 | 'Why', I hear you ask, 'would anyone even _want_ documentation | 
 | 5 | for them sysctl files? If anybody really needs it, it's all in | 
 | 6 | the source...' | 
 | 7 |  | 
 | 8 | Well, this documentation is written because some people either | 
 | 9 | don't know they need to tweak something, or because they don't | 
 | 10 | have the time or knowledge to read the source code. | 
 | 11 |  | 
 | 12 | Furthermore, the programmers who built sysctl have built it to | 
 | 13 | be actually used, not just for the fun of programming it :-) | 
 | 14 |  | 
 | 15 | ============================================================== | 
 | 16 |  | 
 | 17 | Legal blurb: | 
 | 18 |  | 
 | 19 | As usual, there are two main things to consider: | 
 | 20 | 1. you get what you pay for | 
 | 21 | 2. it's free | 
 | 22 |  | 
 | 23 | The consequences are that I won't guarantee the correctness of | 
 | 24 | this document, and if you come to me complaining about how you | 
 | 25 | screwed up your system because of wrong documentation, I won't | 
 | 26 | feel sorry for you. I might even laugh at you... | 
 | 27 |  | 
 | 28 | But of course, if you _do_ manage to screw up your system using | 
 | 29 | only the sysctl options used in this file, I'd like to hear of | 
 | 30 | it. Not only to have a great laugh, but also to make sure that | 
 | 31 | you're the last RTFMing person to screw up. | 
 | 32 |  | 
 | 33 | In short, e-mail your suggestions, corrections and / or horror | 
 | 34 | stories to: <riel@nl.linux.org> | 
 | 35 |  | 
 | 36 | Rik van Riel. | 
 | 37 |  | 
 | 38 | ============================================================== | 
 | 39 |  | 
 | 40 | Introduction: | 
 | 41 |  | 
 | 42 | Sysctl is a means of configuring certain aspects of the kernel | 
 | 43 | at run-time, and the /proc/sys/ directory is there so that you | 
 | 44 | don't even need special tools to do it! | 
 | 45 | In fact, there are only four things needed to use these config | 
 | 46 | facilities: | 
 | 47 | - a running Linux system | 
 | 48 | - root access | 
 | 49 | - common sense (this is especially hard to come by these days) | 
 | 50 | - knowledge of what all those values mean | 
 | 51 |  | 
 | 52 | As a quick 'ls /proc/sys' will show, the directory consists of | 
 | 53 | several (arch-dependent?) subdirs. Each subdir is mainly about | 
 | 54 | one part of the kernel, so you can do configuration on a piece | 
 | 55 | by piece basis, or just some 'thematic frobbing'. | 
 | 56 |  | 
 | 57 | The subdirs are about: | 
 | 58 | abi/		execution domains & personalities | 
 | 59 | debug/		<empty> | 
 | 60 | dev/		device specific information (eg dev/cdrom/info) | 
 | 61 | fs/		specific filesystems | 
 | 62 | 		filehandle, inode, dentry and quota tuning | 
 | 63 | 		binfmt_misc <Documentation/binfmt_misc.txt> | 
 | 64 | kernel/		global kernel info / tuning | 
 | 65 | 		miscellaneous stuff | 
 | 66 | net/		networking stuff, for documentation look in: | 
 | 67 | 		<Documentation/networking/> | 
 | 68 | proc/		<empty> | 
 | 69 | sunrpc/		SUN Remote Procedure Call (NFS) | 
 | 70 | vm/		memory management tuning | 
 | 71 | 		buffer and cache management | 
 | 72 |  | 
 | 73 | These are the subdirs I have on my system. There might be more | 
 | 74 | or other subdirs in another setup. If you see another dir, I'd | 
 | 75 | really like to hear about it :-) |