195cf453d2
Add vm.highmem_is_dirtyable toggle A 32 bit machine with HIGHMEM64 enabled running DCC has an MMAPed file of approximately 2Gb size which contains a hash format that is written randomly by the dbclean process. On 2.6.16 this process took a few minutes. With lowmem only accounting of dirty ratios, this takes about 12 hours of 100% disk IO, all random writes. Include a toggle in /proc/sys/vm/highmem_is_dirtyable which can be set to 1 to add the highmem back to the total available memory count. [akpm@linux-foundation.org: Fix the CONFIG_DETECT_SOFTLOCKUP=y build] Signed-off-by: Bron Gondwana <brong@fastmail.fm> Cc: Ethan Solomita <solo@google.com> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl> Cc: WU Fengguang <wfg@mail.ustc.edu.cn> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org> |
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| .. | ||
| 00-INDEX | ||
| abi.txt | ||
| ctl_unnumbered.txt | ||
| fs.txt | ||
| kernel.txt | ||
| README | ||
| sunrpc.txt | ||
| vm.txt | ||
Documentation for /proc/sys/ kernel version 2.2.10 (c) 1998, 1999, Rik van Riel riel@nl.linux.org
'Why', I hear you ask, 'would anyone even want documentation for them sysctl files? If anybody really needs it, it's all in the source...'
Well, this documentation is written because some people either don't know they need to tweak something, or because they don't have the time or knowledge to read the source code.
Furthermore, the programmers who built sysctl have built it to be actually used, not just for the fun of programming it :-)
==============================================================
Legal blurb:
As usual, there are two main things to consider:
- you get what you pay for
- it's free
The consequences are that I won't guarantee the correctness of this document, and if you come to me complaining about how you screwed up your system because of wrong documentation, I won't feel sorry for you. I might even laugh at you...
But of course, if you do manage to screw up your system using only the sysctl options used in this file, I'd like to hear of it. Not only to have a great laugh, but also to make sure that you're the last RTFMing person to screw up.
In short, e-mail your suggestions, corrections and / or horror stories to: riel@nl.linux.org
Rik van Riel.
==============================================================
Introduction:
Sysctl is a means of configuring certain aspects of the kernel at run-time, and the /proc/sys/ directory is there so that you don't even need special tools to do it! In fact, there are only four things needed to use these config facilities:
- a running Linux system
- root access
- common sense (this is especially hard to come by these days)
- knowledge of what all those values mean
As a quick 'ls /proc/sys' will show, the directory consists of several (arch-dependent?) subdirs. Each subdir is mainly about one part of the kernel, so you can do configuration on a piece by piece basis, or just some 'thematic frobbing'.
The subdirs are about: abi/ execution domains & personalities debug/ dev/ device specific information (eg dev/cdrom/info) fs/ specific filesystems filehandle, inode, dentry and quota tuning binfmt_misc <Documentation/binfmt_misc.txt> kernel/ global kernel info / tuning miscellaneous stuff net/ networking stuff, for documentation look in: <Documentation/networking/> proc/ sunrpc/ SUN Remote Procedure Call (NFS) vm/ memory management tuning buffer and cache management
These are the subdirs I have on my system. There might be more or other subdirs in another setup. If you see another dir, I'd really like to hear about it :-)