mirror of
https://github.com/torvalds/linux.git
synced 2024-11-25 21:51:40 +00:00
docs: blockdev: convert to ReST
Rename the blockdev documentation files to ReST, add an index for them and adjust in order to produce a nice html output via the Sphinx build system. The drbd sub-directory contains some graphs and data flows. Add those too to the documentation. At its new index.rst, let's add a :orphan: while this is not linked to the main index.rst file, in order to avoid build warnings. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>
This commit is contained in:
Mauro Carvalho Chehab
parent
e0ae154404
commit
39443104c7
@ -1249,7 +1249,7 @@
|
||||
See also Documentation/fault-injection/.
|
||||
|
||||
floppy= [HW]
|
||||
See Documentation/blockdev/floppy.txt.
|
||||
See Documentation/blockdev/floppy.rst.
|
||||
|
||||
force_pal_cache_flush
|
||||
[IA-64] Avoid check_sal_cache_flush which may hang on
|
||||
@ -2234,7 +2234,7 @@
|
||||
memblock=debug [KNL] Enable memblock debug messages.
|
||||
|
||||
load_ramdisk= [RAM] List of ramdisks to load from floppy
|
||||
See Documentation/blockdev/ramdisk.txt.
|
||||
See Documentation/blockdev/ramdisk.rst.
|
||||
|
||||
lockd.nlm_grace_period=P [NFS] Assign grace period.
|
||||
Format: <integer>
|
||||
@ -3268,7 +3268,7 @@
|
||||
|
||||
pcd. [PARIDE]
|
||||
See header of drivers/block/paride/pcd.c.
|
||||
See also Documentation/blockdev/paride.txt.
|
||||
See also Documentation/blockdev/paride.rst.
|
||||
|
||||
pci=option[,option...] [PCI] various PCI subsystem options.
|
||||
|
||||
@ -3512,7 +3512,7 @@
|
||||
needed on a platform with proper driver support.
|
||||
|
||||
pd. [PARIDE]
|
||||
See Documentation/blockdev/paride.txt.
|
||||
See Documentation/blockdev/paride.rst.
|
||||
|
||||
pdcchassis= [PARISC,HW] Disable/Enable PDC Chassis Status codes at
|
||||
boot time.
|
||||
@ -3527,10 +3527,10 @@
|
||||
and performance comparison.
|
||||
|
||||
pf. [PARIDE]
|
||||
See Documentation/blockdev/paride.txt.
|
||||
See Documentation/blockdev/paride.rst.
|
||||
|
||||
pg. [PARIDE]
|
||||
See Documentation/blockdev/paride.txt.
|
||||
See Documentation/blockdev/paride.rst.
|
||||
|
||||
pirq= [SMP,APIC] Manual mp-table setup
|
||||
See Documentation/x86/i386/IO-APIC.rst.
|
||||
@ -3642,7 +3642,7 @@
|
||||
|
||||
prompt_ramdisk= [RAM] List of RAM disks to prompt for floppy disk
|
||||
before loading.
|
||||
See Documentation/blockdev/ramdisk.txt.
|
||||
See Documentation/blockdev/ramdisk.rst.
|
||||
|
||||
psi= [KNL] Enable or disable pressure stall information
|
||||
tracking.
|
||||
@ -3664,7 +3664,7 @@
|
||||
pstore.backend= Specify the name of the pstore backend to use
|
||||
|
||||
pt. [PARIDE]
|
||||
See Documentation/blockdev/paride.txt.
|
||||
See Documentation/blockdev/paride.rst.
|
||||
|
||||
pti= [X86_64] Control Page Table Isolation of user and
|
||||
kernel address spaces. Disabling this feature
|
||||
@ -3693,7 +3693,7 @@
|
||||
See Documentation/admin-guide/md.rst.
|
||||
|
||||
ramdisk_size= [RAM] Sizes of RAM disks in kilobytes
|
||||
See Documentation/blockdev/ramdisk.txt.
|
||||
See Documentation/blockdev/ramdisk.rst.
|
||||
|
||||
random.trust_cpu={on,off}
|
||||
[KNL] Enable or disable trusting the use of the
|
||||
|
||||
@ -1,3 +1,7 @@
|
||||
================================
|
||||
kernel data structure for DRBD-9
|
||||
================================
|
||||
|
||||
This describes the in kernel data structure for DRBD-9. Starting with
|
||||
Linux v3.14 we are reorganizing DRBD to use this data structure.
|
||||
|
||||
@ -10,7 +14,7 @@ device is represented by a block device locally.
|
||||
|
||||
The DRBD objects are interconnected to form a matrix as depicted below; a
|
||||
drbd_peer_device object sits at each intersection between a drbd_device and a
|
||||
drbd_connection:
|
||||
drbd_connection::
|
||||
|
||||
/--------------+---------------+.....+---------------\
|
||||
| resource | device | | device |
|
||||
28
Documentation/blockdev/drbd/figures.rst
Normal file
28
Documentation/blockdev/drbd/figures.rst
Normal file
@ -0,0 +1,28 @@
|
||||
.. The here included files are intended to help understand the implementation
|
||||
|
||||
Data flows that Relate some functions, and write packets
|
||||
========================================================
|
||||
|
||||
.. kernel-figure:: DRBD-8.3-data-packets.svg
|
||||
:alt: DRBD-8.3-data-packets.svg
|
||||
:align: center
|
||||
|
||||
.. kernel-figure:: DRBD-data-packets.svg
|
||||
:alt: DRBD-data-packets.svg
|
||||
:align: center
|
||||
|
||||
|
||||
Sub graphs of DRBD's state transitions
|
||||
======================================
|
||||
|
||||
.. kernel-figure:: conn-states-8.dot
|
||||
:alt: conn-states-8.dot
|
||||
:align: center
|
||||
|
||||
.. kernel-figure:: disk-states-8.dot
|
||||
:alt: disk-states-8.dot
|
||||
:align: center
|
||||
|
||||
.. kernel-figure:: node-states-8.dot
|
||||
:alt: node-states-8.dot
|
||||
:align: center
|
||||
@ -1,4 +1,9 @@
|
||||
==========================================
|
||||
Distributed Replicated Block Device - DRBD
|
||||
==========================================
|
||||
|
||||
Description
|
||||
===========
|
||||
|
||||
DRBD is a shared-nothing, synchronously replicated block device. It
|
||||
is designed to serve as a building block for high availability
|
||||
@ -7,10 +12,8 @@ Description
|
||||
|
||||
Please visit http://www.drbd.org to find out more.
|
||||
|
||||
The here included files are intended to help understand the implementation
|
||||
.. toctree::
|
||||
:maxdepth: 1
|
||||
|
||||
DRBD-8.3-data-packets.svg, DRBD-data-packets.svg
|
||||
relates some functions, and write packets.
|
||||
|
||||
conn-states-8.dot, disk-states-8.dot, node-states-8.dot
|
||||
The sub graphs of DRBD's state transitions
|
||||
data-structure-v9
|
||||
figures
|
||||
@ -1,35 +1,37 @@
|
||||
This file describes the floppy driver.
|
||||
=============
|
||||
Floppy Driver
|
||||
=============
|
||||
|
||||
FAQ list:
|
||||
=========
|
||||
|
||||
A FAQ list may be found in the fdutils package (see below), and also
|
||||
A FAQ list may be found in the fdutils package (see below), and also
|
||||
at <http://fdutils.linux.lu/faq.html>.
|
||||
|
||||
|
||||
LILO configuration options (Thinkpad users, read this)
|
||||
======================================================
|
||||
|
||||
The floppy driver is configured using the 'floppy=' option in
|
||||
The floppy driver is configured using the 'floppy=' option in
|
||||
lilo. This option can be typed at the boot prompt, or entered in the
|
||||
lilo configuration file.
|
||||
|
||||
Example: If your kernel is called linux-2.6.9, type the following line
|
||||
at the lilo boot prompt (if you have a thinkpad):
|
||||
Example: If your kernel is called linux-2.6.9, type the following line
|
||||
at the lilo boot prompt (if you have a thinkpad)::
|
||||
|
||||
linux-2.6.9 floppy=thinkpad
|
||||
|
||||
You may also enter the following line in /etc/lilo.conf, in the description
|
||||
of linux-2.6.9:
|
||||
of linux-2.6.9::
|
||||
|
||||
append = "floppy=thinkpad"
|
||||
|
||||
Several floppy related options may be given, example:
|
||||
Several floppy related options may be given, example::
|
||||
|
||||
linux-2.6.9 floppy=daring floppy=two_fdc
|
||||
append = "floppy=daring floppy=two_fdc"
|
||||
|
||||
If you give options both in the lilo config file and on the boot
|
||||
If you give options both in the lilo config file and on the boot
|
||||
prompt, the option strings of both places are concatenated, the boot
|
||||
prompt options coming last. That's why there are also options to
|
||||
restore the default behavior.
|
||||
@ -38,21 +40,23 @@ restore the default behavior.
|
||||
Module configuration options
|
||||
============================
|
||||
|
||||
If you use the floppy driver as a module, use the following syntax:
|
||||
modprobe floppy floppy="<options>"
|
||||
If you use the floppy driver as a module, use the following syntax::
|
||||
|
||||
Example:
|
||||
modprobe floppy floppy="omnibook messages"
|
||||
modprobe floppy floppy="<options>"
|
||||
|
||||
If you need certain options enabled every time you load the floppy driver,
|
||||
you can put:
|
||||
Example::
|
||||
|
||||
options floppy floppy="omnibook messages"
|
||||
modprobe floppy floppy="omnibook messages"
|
||||
|
||||
If you need certain options enabled every time you load the floppy driver,
|
||||
you can put::
|
||||
|
||||
options floppy floppy="omnibook messages"
|
||||
|
||||
in a configuration file in /etc/modprobe.d/.
|
||||
|
||||
|
||||
The floppy driver related options are:
|
||||
The floppy driver related options are:
|
||||
|
||||
floppy=asus_pci
|
||||
Sets the bit mask to allow only units 0 and 1. (default)
|
||||
@ -70,8 +74,7 @@ in a configuration file in /etc/modprobe.d/.
|
||||
Tells the floppy driver that you have only one floppy controller.
|
||||
(default)
|
||||
|
||||
floppy=two_fdc
|
||||
floppy=<address>,two_fdc
|
||||
floppy=two_fdc / floppy=<address>,two_fdc
|
||||
Tells the floppy driver that you have two floppy controllers.
|
||||
The second floppy controller is assumed to be at <address>.
|
||||
This option is not needed if the second controller is at address
|
||||
@ -84,8 +87,7 @@ in a configuration file in /etc/modprobe.d/.
|
||||
floppy=0,thinkpad
|
||||
Tells the floppy driver that you don't have a Thinkpad.
|
||||
|
||||
floppy=omnibook
|
||||
floppy=nodma
|
||||
floppy=omnibook / floppy=nodma
|
||||
Tells the floppy driver not to use Dma for data transfers.
|
||||
This is needed on HP Omnibooks, which don't have a workable
|
||||
DMA channel for the floppy driver. This option is also useful
|
||||
@ -144,14 +146,16 @@ in a configuration file in /etc/modprobe.d/.
|
||||
described in the physical CMOS), or if your BIOS uses
|
||||
non-standard CMOS types. The CMOS types are:
|
||||
|
||||
0 - Use the value of the physical CMOS
|
||||
1 - 5 1/4 DD
|
||||
2 - 5 1/4 HD
|
||||
3 - 3 1/2 DD
|
||||
4 - 3 1/2 HD
|
||||
5 - 3 1/2 ED
|
||||
6 - 3 1/2 ED
|
||||
16 - unknown or not installed
|
||||
== ==================================
|
||||
0 Use the value of the physical CMOS
|
||||
1 5 1/4 DD
|
||||
2 5 1/4 HD
|
||||
3 3 1/2 DD
|
||||
4 3 1/2 HD
|
||||
5 3 1/2 ED
|
||||
6 3 1/2 ED
|
||||
16 unknown or not installed
|
||||
== ==================================
|
||||
|
||||
(Note: there are two valid types for ED drives. This is because 5 was
|
||||
initially chosen to represent floppy *tapes*, and 6 for ED drives.
|
||||
@ -162,8 +166,7 @@ in a configuration file in /etc/modprobe.d/.
|
||||
Print a warning message when an unexpected interrupt is received.
|
||||
(default)
|
||||
|
||||
floppy=no_unexpected_interrupts
|
||||
floppy=L40SX
|
||||
floppy=no_unexpected_interrupts / floppy=L40SX
|
||||
Don't print a message when an unexpected interrupt is received. This
|
||||
is needed on IBM L40SX laptops in certain video modes. (There seems
|
||||
to be an interaction between video and floppy. The unexpected
|
||||
@ -199,47 +202,54 @@ in a configuration file in /etc/modprobe.d/.
|
||||
Sets the floppy DMA channel to <nr> instead of 2.
|
||||
|
||||
floppy=slow
|
||||
Use PS/2 stepping rate:
|
||||
" PS/2 floppies have much slower step rates than regular floppies.
|
||||
Use PS/2 stepping rate::
|
||||
|
||||
PS/2 floppies have much slower step rates than regular floppies.
|
||||
It's been recommended that take about 1/4 of the default speed
|
||||
in some more extreme cases."
|
||||
in some more extreme cases.
|
||||
|
||||
|
||||
Supporting utilities and additional documentation:
|
||||
==================================================
|
||||
|
||||
Additional parameters of the floppy driver can be configured at
|
||||
Additional parameters of the floppy driver can be configured at
|
||||
runtime. Utilities which do this can be found in the fdutils package.
|
||||
This package also contains a new version of mtools which allows to
|
||||
access high capacity disks (up to 1992K on a high density 3 1/2 disk!).
|
||||
It also contains additional documentation about the floppy driver.
|
||||
|
||||
The latest version can be found at fdutils homepage:
|
||||
|
||||
http://fdutils.linux.lu
|
||||
|
||||
The fdutils releases can be found at:
|
||||
|
||||
http://fdutils.linux.lu/download.html
|
||||
|
||||
http://www.tux.org/pub/knaff/fdutils/
|
||||
|
||||
ftp://metalab.unc.edu/pub/Linux/utils/disk-management/
|
||||
|
||||
Reporting problems about the floppy driver
|
||||
==========================================
|
||||
|
||||
If you have a question or a bug report about the floppy driver, mail
|
||||
If you have a question or a bug report about the floppy driver, mail
|
||||
me at Alain.Knaff@poboxes.com . If you post to Usenet, preferably use
|
||||
comp.os.linux.hardware. As the volume in these groups is rather high,
|
||||
be sure to include the word "floppy" (or "FLOPPY") in the subject
|
||||
line. If the reported problem happens when mounting floppy disks, be
|
||||
sure to mention also the type of the filesystem in the subject line.
|
||||
|
||||
Be sure to read the FAQ before mailing/posting any bug reports!
|
||||
Be sure to read the FAQ before mailing/posting any bug reports!
|
||||
|
||||
Alain
|
||||
Alain
|
||||
|
||||
Changelog
|
||||
=========
|
||||
|
||||
10-30-2004 : Cleanup, updating, add reference to module configuration.
|
||||
10-30-2004 :
|
||||
Cleanup, updating, add reference to module configuration.
|
||||
James Nelson <james4765@gmail.com>
|
||||
|
||||
6-3-2000 : Original Document
|
||||
6-3-2000 :
|
||||
Original Document
|
||||
16
Documentation/blockdev/index.rst
Normal file
16
Documentation/blockdev/index.rst
Normal file
@ -0,0 +1,16 @@
|
||||
:orphan:
|
||||
|
||||
===========================
|
||||
The Linux RapidIO Subsystem
|
||||
===========================
|
||||
|
||||
.. toctree::
|
||||
:maxdepth: 1
|
||||
|
||||
floppy
|
||||
nbd
|
||||
paride
|
||||
ramdisk
|
||||
zram
|
||||
|
||||
drbd/index
|
||||
@ -1,3 +1,4 @@
|
||||
==================================
|
||||
Network Block Device (TCP version)
|
||||
==================================
|
||||
|
||||
@ -28,4 +29,3 @@ max_part
|
||||
|
||||
nbds_max
|
||||
Number of block devices that should be initialized (default: 16).
|
||||
|
||||
@ -1,15 +1,17 @@
|
||||
|
||||
Linux and parallel port IDE devices
|
||||
===================================
|
||||
Linux and parallel port IDE devices
|
||||
===================================
|
||||
|
||||
PARIDE v1.03 (c) 1997-8 Grant Guenther <grant@torque.net>
|
||||
|
||||
1. Introduction
|
||||
===============
|
||||
|
||||
Owing to the simplicity and near universality of the parallel port interface
|
||||
to personal computers, many external devices such as portable hard-disk,
|
||||
CD-ROM, LS-120 and tape drives use the parallel port to connect to their
|
||||
host computer. While some devices (notably scanners) use ad-hoc methods
|
||||
to pass commands and data through the parallel port interface, most
|
||||
to pass commands and data through the parallel port interface, most
|
||||
external devices are actually identical to an internal model, but with
|
||||
a parallel-port adapter chip added in. Some of the original parallel port
|
||||
adapters were little more than mechanisms for multiplexing a SCSI bus.
|
||||
@ -28,47 +30,50 @@ were to open up a parallel port CD-ROM drive, for instance, one would
|
||||
find a standard ATAPI CD-ROM drive, a power supply, and a single adapter
|
||||
that interconnected a standard PC parallel port cable and a standard
|
||||
IDE cable. It is usually possible to exchange the CD-ROM device with
|
||||
any other device using the IDE interface.
|
||||
any other device using the IDE interface.
|
||||
|
||||
The document describes the support in Linux for parallel port IDE
|
||||
devices. It does not cover parallel port SCSI devices, "ditto" tape
|
||||
drives or scanners. Many different devices are supported by the
|
||||
drives or scanners. Many different devices are supported by the
|
||||
parallel port IDE subsystem, including:
|
||||
|
||||
MicroSolutions backpack CD-ROM
|
||||
MicroSolutions backpack PD/CD
|
||||
MicroSolutions backpack hard-drives
|
||||
MicroSolutions backpack 8000t tape drive
|
||||
SyQuest EZ-135, EZ-230 & SparQ drives
|
||||
Avatar Shark
|
||||
Imation Superdisk LS-120
|
||||
Maxell Superdisk LS-120
|
||||
FreeCom Power CD
|
||||
Hewlett-Packard 5GB and 8GB tape drives
|
||||
Hewlett-Packard 7100 and 7200 CD-RW drives
|
||||
- MicroSolutions backpack CD-ROM
|
||||
- MicroSolutions backpack PD/CD
|
||||
- MicroSolutions backpack hard-drives
|
||||
- MicroSolutions backpack 8000t tape drive
|
||||
- SyQuest EZ-135, EZ-230 & SparQ drives
|
||||
- Avatar Shark
|
||||
- Imation Superdisk LS-120
|
||||
- Maxell Superdisk LS-120
|
||||
- FreeCom Power CD
|
||||
- Hewlett-Packard 5GB and 8GB tape drives
|
||||
- Hewlett-Packard 7100 and 7200 CD-RW drives
|
||||
|
||||
as well as most of the clone and no-name products on the market.
|
||||
|
||||
To support such a wide range of devices, PARIDE, the parallel port IDE
|
||||
subsystem, is actually structured in three parts. There is a base
|
||||
paride module which provides a registry and some common methods for
|
||||
accessing the parallel ports. The second component is a set of
|
||||
high-level drivers for each of the different types of supported devices:
|
||||
accessing the parallel ports. The second component is a set of
|
||||
high-level drivers for each of the different types of supported devices:
|
||||
|
||||
=== =============
|
||||
pd IDE disk
|
||||
pcd ATAPI CD-ROM
|
||||
pf ATAPI disk
|
||||
pt ATAPI tape
|
||||
pg ATAPI generic
|
||||
=== =============
|
||||
|
||||
(Currently, the pg driver is only used with CD-R drives).
|
||||
|
||||
The high-level drivers function according to the relevant standards.
|
||||
The third component of PARIDE is a set of low-level protocol drivers
|
||||
for each of the parallel port IDE adapter chips. Thanks to the interest
|
||||
and encouragement of Linux users from many parts of the world,
|
||||
and encouragement of Linux users from many parts of the world,
|
||||
support is available for almost all known adapter protocols:
|
||||
|
||||
==== ====================================== ====
|
||||
aten ATEN EH-100 (HK)
|
||||
bpck Microsolutions backpack (US)
|
||||
comm DataStor (old-type) "commuter" adapter (TW)
|
||||
@ -83,9 +88,11 @@ support is available for almost all known adapter protocols:
|
||||
ktti KT Technology PHd adapter (SG)
|
||||
on20 OnSpec 90c20 (US)
|
||||
on26 OnSpec 90c26 (US)
|
||||
==== ====================================== ====
|
||||
|
||||
|
||||
2. Using the PARIDE subsystem
|
||||
=============================
|
||||
|
||||
While configuring the Linux kernel, you may choose either to build
|
||||
the PARIDE drivers into your kernel, or to build them as modules.
|
||||
@ -94,10 +101,10 @@ In either case, you will need to select "Parallel port IDE device support"
|
||||
as well as at least one of the high-level drivers and at least one
|
||||
of the parallel port communication protocols. If you do not know
|
||||
what kind of parallel port adapter is used in your drive, you could
|
||||
begin by checking the file names and any text files on your DOS
|
||||
begin by checking the file names and any text files on your DOS
|
||||
installation floppy. Alternatively, you can look at the markings on
|
||||
the adapter chip itself. That's usually sufficient to identify the
|
||||
correct device.
|
||||
correct device.
|
||||
|
||||
You can actually select all the protocol modules, and allow the PARIDE
|
||||
subsystem to try them all for you.
|
||||
@ -105,8 +112,9 @@ subsystem to try them all for you.
|
||||
For the "brand-name" products listed above, here are the protocol
|
||||
and high-level drivers that you would use:
|
||||
|
||||
================ ============ ====== ========
|
||||
Manufacturer Model Driver Protocol
|
||||
|
||||
================ ============ ====== ========
|
||||
MicroSolutions CD-ROM pcd bpck
|
||||
MicroSolutions PD drive pf bpck
|
||||
MicroSolutions hard-drive pd bpck
|
||||
@ -119,8 +127,10 @@ and high-level drivers that you would use:
|
||||
Hewlett-Packard 5GB Tape pt epat
|
||||
Hewlett-Packard 7200e (CD) pcd epat
|
||||
Hewlett-Packard 7200e (CD-R) pg epat
|
||||
================ ============ ====== ========
|
||||
|
||||
2.1 Configuring built-in drivers
|
||||
---------------------------------
|
||||
|
||||
We recommend that you get to know how the drivers work and how to
|
||||
configure them as loadable modules, before attempting to compile a
|
||||
@ -143,7 +153,7 @@ protocol identification number and, for some devices, the drive's
|
||||
chain ID. While your system is booting, a number of messages are
|
||||
displayed on the console. Like all such messages, they can be
|
||||
reviewed with the 'dmesg' command. Among those messages will be
|
||||
some lines like:
|
||||
some lines like::
|
||||
|
||||
paride: bpck registered as protocol 0
|
||||
paride: epat registered as protocol 1
|
||||
@ -158,10 +168,10 @@ the last two digits of the drive's serial number (but read MicroSolutions'
|
||||
documentation about this).
|
||||
|
||||
As an example, let's assume that you have a MicroSolutions PD/CD drive
|
||||
with unit ID number 36 connected to the parallel port at 0x378, a SyQuest
|
||||
EZ-135 connected to the chained port on the PD/CD drive and also an
|
||||
Imation Superdisk connected to port 0x278. You could give the following
|
||||
options on your boot command:
|
||||
with unit ID number 36 connected to the parallel port at 0x378, a SyQuest
|
||||
EZ-135 connected to the chained port on the PD/CD drive and also an
|
||||
Imation Superdisk connected to port 0x278. You could give the following
|
||||
options on your boot command::
|
||||
|
||||
pd.drive0=0x378,1 pf.drive0=0x278,1 pf.drive1=0x378,0,36
|
||||
|
||||
@ -169,24 +179,27 @@ In the last option, pf.drive1 configures device /dev/pf1, the 0x378
|
||||
is the parallel port base address, the 0 is the protocol registration
|
||||
number and 36 is the chain ID.
|
||||
|
||||
Please note: while PARIDE will work both with and without the
|
||||
Please note: while PARIDE will work both with and without the
|
||||
PARPORT parallel port sharing system that is included by the
|
||||
"Parallel port support" option, PARPORT must be included and enabled
|
||||
if you want to use chains of devices on the same parallel port.
|
||||
|
||||
2.2 Loading and configuring PARIDE as modules
|
||||
----------------------------------------------
|
||||
|
||||
It is much faster and simpler to get to understand the PARIDE drivers
|
||||
if you use them as loadable kernel modules.
|
||||
if you use them as loadable kernel modules.
|
||||
|
||||
Note 1: using these drivers with the "kerneld" automatic module loading
|
||||
system is not recommended for beginners, and is not documented here.
|
||||
Note 1:
|
||||
using these drivers with the "kerneld" automatic module loading
|
||||
system is not recommended for beginners, and is not documented here.
|
||||
|
||||
Note 2: if you build PARPORT support as a loadable module, PARIDE must
|
||||
also be built as loadable modules, and PARPORT must be loaded before the
|
||||
PARIDE modules.
|
||||
Note 2:
|
||||
if you build PARPORT support as a loadable module, PARIDE must
|
||||
also be built as loadable modules, and PARPORT must be loaded before
|
||||
the PARIDE modules.
|
||||
|
||||
To use PARIDE, you must begin by
|
||||
To use PARIDE, you must begin by::
|
||||
|
||||
insmod paride
|
||||
|
||||
@ -195,8 +208,8 @@ among other tasks.
|
||||
|
||||
Then, load as many of the protocol modules as you think you might need.
|
||||
As you load each module, it will register the protocols that it supports,
|
||||
and print a log message to your kernel log file and your console. For
|
||||
example:
|
||||
and print a log message to your kernel log file and your console. For
|
||||
example::
|
||||
|
||||
# insmod epat
|
||||
paride: epat registered as protocol 0
|
||||
@ -205,22 +218,22 @@ example:
|
||||
paride: k971 registered as protocol 2
|
||||
|
||||
Finally, you can load high-level drivers for each kind of device that
|
||||
you have connected. By default, each driver will autoprobe for a single
|
||||
you have connected. By default, each driver will autoprobe for a single
|
||||
device, but you can support up to four similar devices by giving their
|
||||
individual co-ordinates when you load the driver.
|
||||
|
||||
For example, if you had two no-name CD-ROM drives both using the
|
||||
KingByte KBIC-951A adapter, one on port 0x378 and the other on 0x3bc
|
||||
you could give the following command:
|
||||
you could give the following command::
|
||||
|
||||
# insmod pcd drive0=0x378,1 drive1=0x3bc,1
|
||||
|
||||
For most adapters, giving a port address and protocol number is sufficient,
|
||||
but check the source files in linux/drivers/block/paride for more
|
||||
but check the source files in linux/drivers/block/paride for more
|
||||
information. (Hopefully someone will write some man pages one day !).
|
||||
|
||||
As another example, here's what happens when PARPORT is installed, and
|
||||
a SyQuest EZ-135 is attached to port 0x378:
|
||||
a SyQuest EZ-135 is attached to port 0x378::
|
||||
|
||||
# insmod paride
|
||||
paride: version 1.0 installed
|
||||
@ -237,46 +250,47 @@ Note that the last line is the output from the generic partition table
|
||||
scanner - in this case it reports that it has found a disk with one partition.
|
||||
|
||||
2.3 Using a PARIDE device
|
||||
--------------------------
|
||||
|
||||
Once the drivers have been loaded, you can access PARIDE devices in the
|
||||
same way as their traditional counterparts. You will probably need to
|
||||
create the device "special files". Here is a simple script that you can
|
||||
cut to a file and execute:
|
||||
cut to a file and execute::
|
||||
|
||||
#!/bin/bash
|
||||
#
|
||||
# mkd -- a script to create the device special files for the PARIDE subsystem
|
||||
#
|
||||
function mkdev {
|
||||
mknod $1 $2 $3 $4 ; chmod 0660 $1 ; chown root:disk $1
|
||||
}
|
||||
#
|
||||
function pd {
|
||||
D=$( printf \\$( printf "x%03x" $[ $1 + 97 ] ) )
|
||||
mkdev pd$D b 45 $[ $1 * 16 ]
|
||||
for P in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
|
||||
do mkdev pd$D$P b 45 $[ $1 * 16 + $P ]
|
||||
done
|
||||
}
|
||||
#
|
||||
cd /dev
|
||||
#
|
||||
for u in 0 1 2 3 ; do pd $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev pcd$u b 46 $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev pf$u b 47 $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev pt$u c 96 $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev npt$u c 96 $[ $u + 128 ] ; done
|
||||
for u in 0 1 2 3 ; do mkdev pg$u c 97 $u ; done
|
||||
#
|
||||
# end of mkd
|
||||
#!/bin/bash
|
||||
#
|
||||
# mkd -- a script to create the device special files for the PARIDE subsystem
|
||||
#
|
||||
function mkdev {
|
||||
mknod $1 $2 $3 $4 ; chmod 0660 $1 ; chown root:disk $1
|
||||
}
|
||||
#
|
||||
function pd {
|
||||
D=$( printf \\$( printf "x%03x" $[ $1 + 97 ] ) )
|
||||
mkdev pd$D b 45 $[ $1 * 16 ]
|
||||
for P in 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15
|
||||
do mkdev pd$D$P b 45 $[ $1 * 16 + $P ]
|
||||
done
|
||||
}
|
||||
#
|
||||
cd /dev
|
||||
#
|
||||
for u in 0 1 2 3 ; do pd $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev pcd$u b 46 $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev pf$u b 47 $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev pt$u c 96 $u ; done
|
||||
for u in 0 1 2 3 ; do mkdev npt$u c 96 $[ $u + 128 ] ; done
|
||||
for u in 0 1 2 3 ; do mkdev pg$u c 97 $u ; done
|
||||
#
|
||||
# end of mkd
|
||||
|
||||
With the device files and drivers in place, you can access PARIDE devices
|
||||
like any other Linux device. For example, to mount a CD-ROM in pcd0, use:
|
||||
like any other Linux device. For example, to mount a CD-ROM in pcd0, use::
|
||||
|
||||
mount /dev/pcd0 /cdrom
|
||||
|
||||
If you have a fresh Avatar Shark cartridge, and the drive is pda, you
|
||||
might do something like:
|
||||
might do something like::
|
||||
|
||||
fdisk /dev/pda -- make a new partition table with
|
||||
partition 1 of type 83
|
||||
@ -289,41 +303,46 @@ might do something like:
|
||||
|
||||
Devices like the Imation superdisk work in the same way, except that
|
||||
they do not have a partition table. For example to make a 120MB
|
||||
floppy that you could share with a DOS system:
|
||||
floppy that you could share with a DOS system::
|
||||
|
||||
mkdosfs /dev/pf0
|
||||
mount /dev/pf0 /mnt
|
||||
|
||||
|
||||
2.4 The pf driver
|
||||
------------------
|
||||
|
||||
The pf driver is intended for use with parallel port ATAPI disk
|
||||
devices. The most common devices in this category are PD drives
|
||||
and LS-120 drives. Traditionally, media for these devices are not
|
||||
partitioned. Consequently, the pf driver does not support partitioned
|
||||
media. This may be changed in a future version of the driver.
|
||||
media. This may be changed in a future version of the driver.
|
||||
|
||||
2.5 Using the pt driver
|
||||
------------------------
|
||||
|
||||
The pt driver for parallel port ATAPI tape drives is a minimal driver.
|
||||
It does not yet support many of the standard tape ioctl operations.
|
||||
It does not yet support many of the standard tape ioctl operations.
|
||||
For best performance, a block size of 32KB should be used. You will
|
||||
probably want to set the parallel port delay to 0, if you can.
|
||||
|
||||
2.6 Using the pg driver
|
||||
------------------------
|
||||
|
||||
The pg driver can be used in conjunction with the cdrecord program
|
||||
to create CD-ROMs. Please get cdrecord version 1.6.1 or later
|
||||
from ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/ . To record CD-R media
|
||||
your parallel port should ideally be set to EPP mode, and the "port delay"
|
||||
should be set to 0. With those settings it is possible to record at 2x
|
||||
from ftp://ftp.fokus.gmd.de/pub/unix/cdrecord/ . To record CD-R media
|
||||
your parallel port should ideally be set to EPP mode, and the "port delay"
|
||||
should be set to 0. With those settings it is possible to record at 2x
|
||||
speed without any buffer underruns. If you cannot get the driver to work
|
||||
in EPP mode, try to use "bidirectional" or "PS/2" mode and 1x speeds only.
|
||||
|
||||
|
||||
3. Troubleshooting
|
||||
==================
|
||||
|
||||
3.1 Use EPP mode if you can
|
||||
----------------------------
|
||||
|
||||
The most common problems that people report with the PARIDE drivers
|
||||
concern the parallel port CMOS settings. At this time, none of the
|
||||
@ -332,6 +351,7 @@ If you are able to do so, please set your parallel port into EPP mode
|
||||
using your CMOS setup procedure.
|
||||
|
||||
3.2 Check the port delay
|
||||
-------------------------
|
||||
|
||||
Some parallel ports cannot reliably transfer data at full speed. To
|
||||
offset the errors, the PARIDE protocol modules introduce a "port
|
||||
@ -347,23 +367,25 @@ read the comments at the beginning of the driver source files in
|
||||
linux/drivers/block/paride.
|
||||
|
||||
3.3 Some drives need a printer reset
|
||||
-------------------------------------
|
||||
|
||||
There appear to be a number of "noname" external drives on the market
|
||||
that do not always power up correctly. We have noticed this with some
|
||||
drives based on OnSpec and older Freecom adapters. In these rare cases,
|
||||
the adapter can often be reinitialised by issuing a "printer reset" on
|
||||
the parallel port. As the reset operation is potentially disruptive in
|
||||
multiple device environments, the PARIDE drivers will not do it
|
||||
automatically. You can however, force a printer reset by doing:
|
||||
the parallel port. As the reset operation is potentially disruptive in
|
||||
multiple device environments, the PARIDE drivers will not do it
|
||||
automatically. You can however, force a printer reset by doing::
|
||||
|
||||
insmod lp reset=1
|
||||
rmmod lp
|
||||
|
||||
If you have one of these marginal cases, you should probably build
|
||||
your paride drivers as modules, and arrange to do the printer reset
|
||||
before loading the PARIDE drivers.
|
||||
before loading the PARIDE drivers.
|
||||
|
||||
3.4 Use the verbose option and dmesg if you need help
|
||||
------------------------------------------------------
|
||||
|
||||
While a lot of testing has gone into these drivers to make them work
|
||||
as smoothly as possible, problems will arise. If you do have problems,
|
||||
@ -373,7 +395,7 @@ clues, then please make sure that only one drive is hooked to your system,
|
||||
and that either (a) PARPORT is enabled or (b) no other device driver
|
||||
is using your parallel port (check in /proc/ioports). Then, load the
|
||||
appropriate drivers (you can load several protocol modules if you want)
|
||||
as in:
|
||||
as in::
|
||||
|
||||
# insmod paride
|
||||
# insmod epat
|
||||
@ -394,12 +416,14 @@ by e-mail to grant@torque.net, or join the linux-parport mailing list
|
||||
and post your report there.
|
||||
|
||||
3.5 For more information or help
|
||||
---------------------------------
|
||||
|
||||
You can join the linux-parport mailing list by sending a mail message
|
||||
to
|
||||
to:
|
||||
|
||||
linux-parport-request@torque.net
|
||||
|
||||
with the single word
|
||||
with the single word::
|
||||
|
||||
subscribe
|
||||
|
||||
@ -412,6 +436,4 @@ have in your mail headers, when sending mail to the list server.
|
||||
You might also find some useful information on the linux-parport
|
||||
web pages (although they are not always up to date) at
|
||||
|
||||
http://web.archive.org/web/*/http://www.torque.net/parport/
|
||||
|
||||
|
||||
http://web.archive.org/web/%2E/http://www.torque.net/parport/
|
||||
@ -1,7 +1,8 @@
|
||||
==========================================
|
||||
Using the RAM disk block device with Linux
|
||||
------------------------------------------
|
||||
==========================================
|
||||
|
||||
Contents:
|
||||
.. Contents:
|
||||
|
||||
1) Overview
|
||||
2) Kernel Command Line Parameters
|
||||
@ -42,7 +43,7 @@ rescue floppy disk.
|
||||
2a) Kernel Command Line Parameters
|
||||
|
||||
ramdisk_size=N
|
||||
==============
|
||||
Size of the ramdisk.
|
||||
|
||||
This parameter tells the RAM disk driver to set up RAM disks of N k size. The
|
||||
default is 4096 (4 MB).
|
||||
@ -50,16 +51,13 @@ default is 4096 (4 MB).
|
||||
2b) Module parameters
|
||||
|
||||
rd_nr
|
||||
=====
|
||||
/dev/ramX devices created.
|
||||
/dev/ramX devices created.
|
||||
|
||||
max_part
|
||||
========
|
||||
Maximum partition number.
|
||||
Maximum partition number.
|
||||
|
||||
rd_size
|
||||
=======
|
||||
See ramdisk_size.
|
||||
See ramdisk_size.
|
||||
|
||||
3) Using "rdev -r"
|
||||
------------------
|
||||
@ -71,11 +69,11 @@ to 2 MB (2^11) of where to find the RAM disk (this used to be the size). Bit
|
||||
prompt/wait sequence is to be given before trying to read the RAM disk. Since
|
||||
the RAM disk dynamically grows as data is being written into it, a size field
|
||||
is not required. Bits 11 to 13 are not currently used and may as well be zero.
|
||||
These numbers are no magical secrets, as seen below:
|
||||
These numbers are no magical secrets, as seen below::
|
||||
|
||||
./arch/x86/kernel/setup.c:#define RAMDISK_IMAGE_START_MASK 0x07FF
|
||||
./arch/x86/kernel/setup.c:#define RAMDISK_PROMPT_FLAG 0x8000
|
||||
./arch/x86/kernel/setup.c:#define RAMDISK_LOAD_FLAG 0x4000
|
||||
./arch/x86/kernel/setup.c:#define RAMDISK_IMAGE_START_MASK 0x07FF
|
||||
./arch/x86/kernel/setup.c:#define RAMDISK_PROMPT_FLAG 0x8000
|
||||
./arch/x86/kernel/setup.c:#define RAMDISK_LOAD_FLAG 0x4000
|
||||
|
||||
Consider a typical two floppy disk setup, where you will have the
|
||||
kernel on disk one, and have already put a RAM disk image onto disk #2.
|
||||
@ -92,20 +90,23 @@ sequence so that you have a chance to switch floppy disks.
|
||||
The command line equivalent is: "prompt_ramdisk=1"
|
||||
|
||||
Putting that together gives 2^15 + 2^14 + 0 = 49152 for an rdev word.
|
||||
So to create disk one of the set, you would do:
|
||||
So to create disk one of the set, you would do::
|
||||
|
||||
/usr/src/linux# cat arch/x86/boot/zImage > /dev/fd0
|
||||
/usr/src/linux# rdev /dev/fd0 /dev/fd0
|
||||
/usr/src/linux# rdev -r /dev/fd0 49152
|
||||
|
||||
If you make a boot disk that has LILO, then for the above, you would use:
|
||||
If you make a boot disk that has LILO, then for the above, you would use::
|
||||
|
||||
append = "ramdisk_start=0 load_ramdisk=1 prompt_ramdisk=1"
|
||||
Since the default start = 0 and the default prompt = 1, you could use:
|
||||
|
||||
Since the default start = 0 and the default prompt = 1, you could use::
|
||||
|
||||
append = "load_ramdisk=1"
|
||||
|
||||
|
||||
4) An Example of Creating a Compressed RAM Disk
|
||||
----------------------------------------------
|
||||
-----------------------------------------------
|
||||
|
||||
To create a RAM disk image, you will need a spare block device to
|
||||
construct it on. This can be the RAM disk device itself, or an
|
||||
@ -120,11 +121,11 @@ a) Decide on the RAM disk size that you want. Say 2 MB for this example.
|
||||
Create it by writing to the RAM disk device. (This step is not currently
|
||||
required, but may be in the future.) It is wise to zero out the
|
||||
area (esp. for disks) so that maximal compression is achieved for
|
||||
the unused blocks of the image that you are about to create.
|
||||
the unused blocks of the image that you are about to create::
|
||||
|
||||
dd if=/dev/zero of=/dev/ram0 bs=1k count=2048
|
||||
|
||||
b) Make a filesystem on it. Say ext2fs for this example.
|
||||
b) Make a filesystem on it. Say ext2fs for this example::
|
||||
|
||||
mke2fs -vm0 /dev/ram0 2048
|
||||
|
||||
@ -133,11 +134,11 @@ c) Mount it, copy the files you want to it (eg: /etc/* /dev/* ...)
|
||||
|
||||
d) Compress the contents of the RAM disk. The level of compression
|
||||
will be approximately 50% of the space used by the files. Unused
|
||||
space on the RAM disk will compress to almost nothing.
|
||||
space on the RAM disk will compress to almost nothing::
|
||||
|
||||
dd if=/dev/ram0 bs=1k count=2048 | gzip -v9 > /tmp/ram_image.gz
|
||||
|
||||
e) Put the kernel onto the floppy
|
||||
e) Put the kernel onto the floppy::
|
||||
|
||||
dd if=zImage of=/dev/fd0 bs=1k
|
||||
|
||||
@ -146,13 +147,13 @@ f) Put the RAM disk image onto the floppy, after the kernel. Use an offset
|
||||
(possibly larger) kernel onto the same floppy later without overlapping
|
||||
the RAM disk image. An offset of 400 kB for kernels about 350 kB in
|
||||
size would be reasonable. Make sure offset+size of ram_image.gz is
|
||||
not larger than the total space on your floppy (usually 1440 kB).
|
||||
not larger than the total space on your floppy (usually 1440 kB)::
|
||||
|
||||
dd if=/tmp/ram_image.gz of=/dev/fd0 bs=1k seek=400
|
||||
|
||||
g) Use "rdev" to set the boot device, RAM disk offset, prompt flag, etc.
|
||||
For prompt_ramdisk=1, load_ramdisk=1, ramdisk_start=400, one would
|
||||
have 2^15 + 2^14 + 400 = 49552.
|
||||
have 2^15 + 2^14 + 400 = 49552::
|
||||
|
||||
rdev /dev/fd0 /dev/fd0
|
||||
rdev -r /dev/fd0 49552
|
||||
@ -160,15 +161,17 @@ g) Use "rdev" to set the boot device, RAM disk offset, prompt flag, etc.
|
||||
That is it. You now have your boot/root compressed RAM disk floppy. Some
|
||||
users may wish to combine steps (d) and (f) by using a pipe.
|
||||
|
||||
--------------------------------------------------------------------------
|
||||
|
||||
Paul Gortmaker 12/95
|
||||
|
||||
Changelog:
|
||||
----------
|
||||
|
||||
10-22-04 : Updated to reflect changes in command line options, remove
|
||||
10-22-04 :
|
||||
Updated to reflect changes in command line options, remove
|
||||
obsolete references, general cleanup.
|
||||
James Nelson (james4765@gmail.com)
|
||||
|
||||
|
||||
12-95 : Original Document
|
||||
12-95 :
|
||||
Original Document
|
||||
@ -1,7 +1,9 @@
|
||||
========================================
|
||||
zram: Compressed RAM based block devices
|
||||
----------------------------------------
|
||||
========================================
|
||||
|
||||
* Introduction
|
||||
Introduction
|
||||
============
|
||||
|
||||
The zram module creates RAM based block devices named /dev/zram<id>
|
||||
(<id> = 0, 1, ...). Pages written to these disks are compressed and stored
|
||||
@ -12,9 +14,11 @@ use as swap disks, various caches under /var and maybe many more :)
|
||||
Statistics for individual zram devices are exported through sysfs nodes at
|
||||
/sys/block/zram<id>/
|
||||
|
||||
* Usage
|
||||
Usage
|
||||
=====
|
||||
|
||||
There are several ways to configure and manage zram device(-s):
|
||||
|
||||
a) using zram and zram_control sysfs attributes
|
||||
b) using zramctl utility, provided by util-linux (util-linux@vger.kernel.org).
|
||||
|
||||
@ -22,7 +26,7 @@ In this document we will describe only 'manual' zram configuration steps,
|
||||
IOW, zram and zram_control sysfs attributes.
|
||||
|
||||
In order to get a better idea about zramctl please consult util-linux
|
||||
documentation, zramctl man-page or `zramctl --help'. Please be informed
|
||||
documentation, zramctl man-page or `zramctl --help`. Please be informed
|
||||
that zram maintainers do not develop/maintain util-linux or zramctl, should
|
||||
you have any questions please contact util-linux@vger.kernel.org
|
||||
|
||||
@ -30,19 +34,23 @@ Following shows a typical sequence of steps for using zram.
|
||||
|
||||
WARNING
|
||||
=======
|
||||
|
||||
For the sake of simplicity we skip error checking parts in most of the
|
||||
examples below. However, it is your sole responsibility to handle errors.
|
||||
|
||||
zram sysfs attributes always return negative values in case of errors.
|
||||
The list of possible return codes:
|
||||
-EBUSY -- an attempt to modify an attribute that cannot be changed once
|
||||
the device has been initialised. Please reset device first;
|
||||
-ENOMEM -- zram was not able to allocate enough memory to fulfil your
|
||||
needs;
|
||||
-EINVAL -- invalid input has been provided.
|
||||
|
||||
======== =============================================================
|
||||
-EBUSY an attempt to modify an attribute that cannot be changed once
|
||||
the device has been initialised. Please reset device first;
|
||||
-ENOMEM zram was not able to allocate enough memory to fulfil your
|
||||
needs;
|
||||
-EINVAL invalid input has been provided.
|
||||
======== =============================================================
|
||||
|
||||
If you use 'echo', the returned value that is changed by 'echo' utility,
|
||||
and, in general case, something like:
|
||||
and, in general case, something like::
|
||||
|
||||
echo 3 > /sys/block/zram0/max_comp_streams
|
||||
if [ $? -ne 0 ];
|
||||
@ -51,7 +59,11 @@ and, in general case, something like:
|
||||
|
||||
should suffice.
|
||||
|
||||
1) Load Module:
|
||||
1) Load Module
|
||||
==============
|
||||
|
||||
::
|
||||
|
||||
modprobe zram num_devices=4
|
||||
This creates 4 devices: /dev/zram{0,1,2,3}
|
||||
|
||||
@ -59,6 +71,8 @@ num_devices parameter is optional and tells zram how many devices should be
|
||||
pre-created. Default: 1.
|
||||
|
||||
2) Set max number of compression streams
|
||||
========================================
|
||||
|
||||
Regardless the value passed to this attribute, ZRAM will always
|
||||
allocate multiple compression streams - one per online CPUs - thus
|
||||
allowing several concurrent compression operations. The number of
|
||||
@ -66,16 +80,20 @@ allocated compression streams goes down when some of the CPUs
|
||||
become offline. There is no single-compression-stream mode anymore,
|
||||
unless you are running a UP system or has only 1 CPU online.
|
||||
|
||||
To find out how many streams are currently available:
|
||||
To find out how many streams are currently available::
|
||||
|
||||
cat /sys/block/zram0/max_comp_streams
|
||||
|
||||
3) Select compression algorithm
|
||||
===============================
|
||||
|
||||
Using comp_algorithm device attribute one can see available and
|
||||
currently selected (shown in square brackets) compression algorithms,
|
||||
change selected compression algorithm (once the device is initialised
|
||||
there is no way to change compression algorithm).
|
||||
|
||||
Examples:
|
||||
Examples::
|
||||
|
||||
#show supported compression algorithms
|
||||
cat /sys/block/zram0/comp_algorithm
|
||||
lzo [lz4]
|
||||
@ -83,20 +101,23 @@ Examples:
|
||||
#select lzo compression algorithm
|
||||
echo lzo > /sys/block/zram0/comp_algorithm
|
||||
|
||||
For the time being, the `comp_algorithm' content does not necessarily
|
||||
For the time being, the `comp_algorithm` content does not necessarily
|
||||
show every compression algorithm supported by the kernel. We keep this
|
||||
list primarily to simplify device configuration and one can configure
|
||||
a new device with a compression algorithm that is not listed in
|
||||
`comp_algorithm'. The thing is that, internally, ZRAM uses Crypto API
|
||||
`comp_algorithm`. The thing is that, internally, ZRAM uses Crypto API
|
||||
and, if some of the algorithms were built as modules, it's impossible
|
||||
to list all of them using, for instance, /proc/crypto or any other
|
||||
method. This, however, has an advantage of permitting the usage of
|
||||
custom crypto compression modules (implementing S/W or H/W compression).
|
||||
|
||||
4) Set Disksize
|
||||
===============
|
||||
|
||||
Set disk size by writing the value to sysfs node 'disksize'.
|
||||
The value can be either in bytes or you can use mem suffixes.
|
||||
Examples:
|
||||
Examples::
|
||||
|
||||
# Initialize /dev/zram0 with 50MB disksize
|
||||
echo $((50*1024*1024)) > /sys/block/zram0/disksize
|
||||
|
||||
@ -111,10 +132,13 @@ since we expect a 2:1 compression ratio. Note that zram uses about 0.1% of the
|
||||
size of the disk when not in use so a huge zram is wasteful.
|
||||
|
||||
5) Set memory limit: Optional
|
||||
=============================
|
||||
|
||||
Set memory limit by writing the value to sysfs node 'mem_limit'.
|
||||
The value can be either in bytes or you can use mem suffixes.
|
||||
In addition, you could change the value in runtime.
|
||||
Examples:
|
||||
Examples::
|
||||
|
||||
# limit /dev/zram0 with 50MB memory
|
||||
echo $((50*1024*1024)) > /sys/block/zram0/mem_limit
|
||||
|
||||
@ -126,7 +150,11 @@ Examples:
|
||||
# To disable memory limit
|
||||
echo 0 > /sys/block/zram0/mem_limit
|
||||
|
||||
6) Activate:
|
||||
6) Activate
|
||||
===========
|
||||
|
||||
::
|
||||
|
||||
mkswap /dev/zram0
|
||||
swapon /dev/zram0
|
||||
|
||||
@ -134,6 +162,7 @@ Examples:
|
||||
mount /dev/zram1 /tmp
|
||||
|
||||
7) Add/remove zram devices
|
||||
==========================
|
||||
|
||||
zram provides a control interface, which enables dynamic (on-demand) device
|
||||
addition and removal.
|
||||
@ -142,37 +171,44 @@ In order to add a new /dev/zramX device, perform read operation on hot_add
|
||||
attribute. This will return either new device's device id (meaning that you
|
||||
can use /dev/zram<id>) or error code.
|
||||
|
||||
Example:
|
||||
Example::
|
||||
|
||||
cat /sys/class/zram-control/hot_add
|
||||
1
|
||||
|
||||
To remove the existing /dev/zramX device (where X is a device id)
|
||||
execute
|
||||
execute::
|
||||
|
||||
echo X > /sys/class/zram-control/hot_remove
|
||||
|
||||
8) Stats:
|
||||
8) Stats
|
||||
========
|
||||
|
||||
Per-device statistics are exported as various nodes under /sys/block/zram<id>/
|
||||
|
||||
A brief description of exported device attributes. For more details please
|
||||
read Documentation/ABI/testing/sysfs-block-zram.
|
||||
|
||||
====================== ====== ===============================================
|
||||
Name access description
|
||||
---- ------ -----------
|
||||
====================== ====== ===============================================
|
||||
disksize RW show and set the device's disk size
|
||||
initstate RO shows the initialization state of the device
|
||||
reset WO trigger device reset
|
||||
mem_used_max WO reset the `mem_used_max' counter (see later)
|
||||
mem_limit WO specifies the maximum amount of memory ZRAM can use
|
||||
to store the compressed data
|
||||
writeback_limit WO specifies the maximum amount of write IO zram can
|
||||
write out to backing device as 4KB unit
|
||||
mem_used_max WO reset the `mem_used_max` counter (see later)
|
||||
mem_limit WO specifies the maximum amount of memory ZRAM can
|
||||
use to store the compressed data
|
||||
writeback_limit WO specifies the maximum amount of write IO zram
|
||||
can write out to backing device as 4KB unit
|
||||
writeback_limit_enable RW show and set writeback_limit feature
|
||||
max_comp_streams RW the number of possible concurrent compress operations
|
||||
max_comp_streams RW the number of possible concurrent compress
|
||||
operations
|
||||
comp_algorithm RW show and change the compression algorithm
|
||||
compact WO trigger memory compaction
|
||||
debug_stat RO this file is used for zram debugging purposes
|
||||
backing_dev RW set up backend storage for zram to write out
|
||||
idle WO mark allocated slot as idle
|
||||
====================== ====== ===============================================
|
||||
|
||||
|
||||
User space is advised to use the following files to read the device statistics.
|
||||
@ -188,23 +224,31 @@ The stat file represents device's I/O statistics not accounted by block
|
||||
layer and, thus, not available in zram<id>/stat file. It consists of a
|
||||
single line of text and contains the following stats separated by
|
||||
whitespace:
|
||||
failed_reads the number of failed reads
|
||||
failed_writes the number of failed writes
|
||||
invalid_io the number of non-page-size-aligned I/O requests
|
||||
|
||||
============= =============================================================
|
||||
failed_reads The number of failed reads
|
||||
failed_writes The number of failed writes
|
||||
invalid_io The number of non-page-size-aligned I/O requests
|
||||
notify_free Depending on device usage scenario it may account
|
||||
|
||||
a) the number of pages freed because of swap slot free
|
||||
notifications or b) the number of pages freed because of
|
||||
REQ_OP_DISCARD requests sent by bio. The former ones are
|
||||
sent to a swap block device when a swap slot is freed,
|
||||
which implies that this disk is being used as a swap disk.
|
||||
notifications
|
||||
b) the number of pages freed because of
|
||||
REQ_OP_DISCARD requests sent by bio. The former ones are
|
||||
sent to a swap block device when a swap slot is freed,
|
||||
which implies that this disk is being used as a swap disk.
|
||||
|
||||
The latter ones are sent by filesystem mounted with
|
||||
discard option, whenever some data blocks are getting
|
||||
discarded.
|
||||
============= =============================================================
|
||||
|
||||
File /sys/block/zram<id>/mm_stat
|
||||
|
||||
The stat file represents device's mm statistics. It consists of a single
|
||||
line of text and contains the following stats separated by whitespace:
|
||||
|
||||
================ =============================================================
|
||||
orig_data_size uncompressed size of data stored in this disk.
|
||||
This excludes same-element-filled pages (same_pages) since
|
||||
no memory is allocated for them.
|
||||
@ -223,58 +267,71 @@ line of text and contains the following stats separated by whitespace:
|
||||
No memory is allocated for such pages.
|
||||
pages_compacted the number of pages freed during compaction
|
||||
huge_pages the number of incompressible pages
|
||||
================ =============================================================
|
||||
|
||||
File /sys/block/zram<id>/bd_stat
|
||||
|
||||
The stat file represents device's backing device statistics. It consists of
|
||||
a single line of text and contains the following stats separated by whitespace:
|
||||
|
||||
============== =============================================================
|
||||
bd_count size of data written in backing device.
|
||||
Unit: 4K bytes
|
||||
bd_reads the number of reads from backing device
|
||||
Unit: 4K bytes
|
||||
bd_writes the number of writes to backing device
|
||||
Unit: 4K bytes
|
||||
============== =============================================================
|
||||
|
||||
9) Deactivate
|
||||
=============
|
||||
|
||||
::
|
||||
|
||||
9) Deactivate:
|
||||
swapoff /dev/zram0
|
||||
umount /dev/zram1
|
||||
|
||||
10) Reset:
|
||||
Write any positive value to 'reset' sysfs node
|
||||
echo 1 > /sys/block/zram0/reset
|
||||
echo 1 > /sys/block/zram1/reset
|
||||
10) Reset
|
||||
=========
|
||||
|
||||
Write any positive value to 'reset' sysfs node::
|
||||
|
||||
echo 1 > /sys/block/zram0/reset
|
||||
echo 1 > /sys/block/zram1/reset
|
||||
|
||||
This frees all the memory allocated for the given device and
|
||||
resets the disksize to zero. You must set the disksize again
|
||||
before reusing the device.
|
||||
|
||||
* Optional Feature
|
||||
Optional Feature
|
||||
================
|
||||
|
||||
= writeback
|
||||
writeback
|
||||
---------
|
||||
|
||||
With CONFIG_ZRAM_WRITEBACK, zram can write idle/incompressible page
|
||||
to backing storage rather than keeping it in memory.
|
||||
To use the feature, admin should set up backing device via
|
||||
To use the feature, admin should set up backing device via::
|
||||
|
||||
"echo /dev/sda5 > /sys/block/zramX/backing_dev"
|
||||
echo /dev/sda5 > /sys/block/zramX/backing_dev
|
||||
|
||||
before disksize setting. It supports only partition at this moment.
|
||||
If admin want to use incompressible page writeback, they could do via
|
||||
If admin want to use incompressible page writeback, they could do via::
|
||||
|
||||
"echo huge > /sys/block/zramX/write"
|
||||
echo huge > /sys/block/zramX/write
|
||||
|
||||
To use idle page writeback, first, user need to declare zram pages
|
||||
as idle.
|
||||
as idle::
|
||||
|
||||
"echo all > /sys/block/zramX/idle"
|
||||
echo all > /sys/block/zramX/idle
|
||||
|
||||
From now on, any pages on zram are idle pages. The idle mark
|
||||
will be removed until someone request access of the block.
|
||||
IOW, unless there is access request, those pages are still idle pages.
|
||||
|
||||
Admin can request writeback of those idle pages at right timing via
|
||||
Admin can request writeback of those idle pages at right timing via::
|
||||
|
||||
"echo idle > /sys/block/zramX/writeback"
|
||||
echo idle > /sys/block/zramX/writeback
|
||||
|
||||
With the command, zram writeback idle pages from memory to the storage.
|
||||
|
||||
@ -285,7 +342,7 @@ to guarantee storage health for entire product life.
|
||||
To overcome the concern, zram supports "writeback_limit" feature.
|
||||
The "writeback_limit_enable"'s default value is 0 so that it doesn't limit
|
||||
any writeback. IOW, if admin want to apply writeback budget, he should
|
||||
enable writeback_limit_enable via
|
||||
enable writeback_limit_enable via::
|
||||
|
||||
$ echo 1 > /sys/block/zramX/writeback_limit_enable
|
||||
|
||||
@ -296,7 +353,7 @@ until admin set the budget via /sys/block/zramX/writeback_limit.
|
||||
assigned via /sys/block/zramX/writeback_limit is meaninless.)
|
||||
|
||||
If admin want to limit writeback as per-day 400M, he could do it
|
||||
like below.
|
||||
like below::
|
||||
|
||||
$ MB_SHIFT=20
|
||||
$ 4K_SHIFT=12
|
||||
@ -305,16 +362,16 @@ like below.
|
||||
$ echo 1 > /sys/block/zram0/writeback_limit_enable
|
||||
|
||||
If admin want to allow further write again once the bugdet is exausted,
|
||||
he could do it like below
|
||||
he could do it like below::
|
||||
|
||||
$ echo $((400<<MB_SHIFT>>4K_SHIFT)) > \
|
||||
/sys/block/zram0/writeback_limit
|
||||
|
||||
If admin want to see remaining writeback budget since he set,
|
||||
If admin want to see remaining writeback budget since he set::
|
||||
|
||||
$ cat /sys/block/zramX/writeback_limit
|
||||
|
||||
If admin want to disable writeback limit, he could do
|
||||
If admin want to disable writeback limit, he could do::
|
||||
|
||||
$ echo 0 > /sys/block/zramX/writeback_limit_enable
|
||||
|
||||
@ -326,25 +383,35 @@ budget in next setting is user's job.
|
||||
If admin want to measure writeback count in a certain period, he could
|
||||
know it via /sys/block/zram0/bd_stat's 3rd column.
|
||||
|
||||
= memory tracking
|
||||
memory tracking
|
||||
===============
|
||||
|
||||
With CONFIG_ZRAM_MEMORY_TRACKING, user can know information of the
|
||||
zram block. It could be useful to catch cold or incompressible
|
||||
pages of the process with*pagemap.
|
||||
|
||||
If you enable the feature, you could see block state via
|
||||
/sys/kernel/debug/zram/zram0/block_state". The output is as follows,
|
||||
/sys/kernel/debug/zram/zram0/block_state". The output is as follows::
|
||||
|
||||
300 75.033841 .wh.
|
||||
301 63.806904 s...
|
||||
302 63.806919 ..hi
|
||||
|
||||
First column is zram's block index.
|
||||
Second column is access time since the system was booted
|
||||
Third column is state of the block.
|
||||
(s: same page
|
||||
w: written page to backing store
|
||||
h: huge page
|
||||
i: idle page)
|
||||
First column
|
||||
zram's block index.
|
||||
Second column
|
||||
access time since the system was booted
|
||||
Third column
|
||||
state of the block:
|
||||
|
||||
s:
|
||||
same page
|
||||
w:
|
||||
written page to backing store
|
||||
h:
|
||||
huge page
|
||||
i:
|
||||
idle page
|
||||
|
||||
First line of above example says 300th block is accessed at 75.033841sec
|
||||
and the block's state is huge so it is written back to the backing
|
||||
@ -11076,7 +11076,7 @@ M: Josef Bacik <josef@toxicpanda.com>
|
||||
S: Maintained
|
||||
L: linux-block@vger.kernel.org
|
||||
L: nbd@other.debian.org
|
||||
F: Documentation/blockdev/nbd.txt
|
||||
F: Documentation/blockdev/nbd.rst
|
||||
F: drivers/block/nbd.c
|
||||
F: include/trace/events/nbd.h
|
||||
F: include/uapi/linux/nbd.h
|
||||
@ -12086,7 +12086,7 @@ PARIDE DRIVERS FOR PARALLEL PORT IDE DEVICES
|
||||
M: Tim Waugh <tim@cyberelk.net>
|
||||
L: linux-parport@lists.infradead.org (subscribers-only)
|
||||
S: Maintained
|
||||
F: Documentation/blockdev/paride.txt
|
||||
F: Documentation/blockdev/paride.rst
|
||||
F: drivers/block/paride/
|
||||
|
||||
PARISC ARCHITECTURE
|
||||
@ -13367,7 +13367,7 @@ F: drivers/net/wireless/ralink/rt2x00/
|
||||
RAMDISK RAM BLOCK DEVICE DRIVER
|
||||
M: Jens Axboe <axboe@kernel.dk>
|
||||
S: Maintained
|
||||
F: Documentation/blockdev/ramdisk.txt
|
||||
F: Documentation/blockdev/ramdisk.rst
|
||||
F: drivers/block/brd.c
|
||||
|
||||
RANCHU VIRTUAL BOARD FOR MIPS
|
||||
@ -17723,7 +17723,7 @@ R: Sergey Senozhatsky <sergey.senozhatsky.work@gmail.com>
|
||||
L: linux-kernel@vger.kernel.org
|
||||
S: Maintained
|
||||
F: drivers/block/zram/
|
||||
F: Documentation/blockdev/zram.txt
|
||||
F: Documentation/blockdev/zram.rst
|
||||
|
||||
ZS DECSTATION Z85C30 SERIAL DRIVER
|
||||
M: "Maciej W. Rozycki" <macro@linux-mips.org>
|
||||
|
||||
@ -31,7 +31,7 @@ config BLK_DEV_FD
|
||||
If you want to use the floppy disk drive(s) of your PC under Linux,
|
||||
say Y. Information about this driver, especially important for IBM
|
||||
Thinkpad users, is contained in
|
||||
<file:Documentation/blockdev/floppy.txt>.
|
||||
<file:Documentation/blockdev/floppy.rst>.
|
||||
That file also contains the location of the Floppy driver FAQ as
|
||||
well as location of the fdutils package used to configure additional
|
||||
parameters of the driver at run time.
|
||||
@ -96,7 +96,7 @@ config PARIDE
|
||||
your computer's parallel port. Most of them are actually IDE devices
|
||||
using a parallel port IDE adapter. This option enables the PARIDE
|
||||
subsystem which contains drivers for many of these external drives.
|
||||
Read <file:Documentation/blockdev/paride.txt> for more information.
|
||||
Read <file:Documentation/blockdev/paride.rst> for more information.
|
||||
|
||||
If you have said Y to the "Parallel-port support" configuration
|
||||
option, you may share a single port between your printer and other
|
||||
@ -261,7 +261,7 @@ config BLK_DEV_NBD
|
||||
userland (making server and client physically the same computer,
|
||||
communicating using the loopback network device).
|
||||
|
||||
Read <file:Documentation/blockdev/nbd.txt> for more information,
|
||||
Read <file:Documentation/blockdev/nbd.rst> for more information,
|
||||
especially about where to find the server code, which runs in user
|
||||
space and does not need special kernel support.
|
||||
|
||||
@ -303,7 +303,7 @@ config BLK_DEV_RAM
|
||||
during the initial install of Linux.
|
||||
|
||||
Note that the kernel command line option "ramdisk=XX" is now obsolete.
|
||||
For details, read <file:Documentation/blockdev/ramdisk.txt>.
|
||||
For details, read <file:Documentation/blockdev/ramdisk.rst>.
|
||||
|
||||
To compile this driver as a module, choose M here: the
|
||||
module will be called brd. An alias "rd" has been defined
|
||||
|
||||
@ -4424,7 +4424,7 @@ static int __init floppy_setup(char *str)
|
||||
pr_cont("\n");
|
||||
} else
|
||||
DPRINT("botched floppy option\n");
|
||||
DPRINT("Read Documentation/blockdev/floppy.txt\n");
|
||||
DPRINT("Read Documentation/blockdev/floppy.rst\n");
|
||||
return 0;
|
||||
}
|
||||
|
||||
|
||||
@ -12,7 +12,7 @@ config ZRAM
|
||||
It has several use cases, for example: /tmp storage, use as swap
|
||||
disks and maybe many more.
|
||||
|
||||
See Documentation/blockdev/zram.txt for more information.
|
||||
See Documentation/blockdev/zram.rst for more information.
|
||||
|
||||
config ZRAM_WRITEBACK
|
||||
bool "Write back incompressible or idle page to backing device"
|
||||
@ -26,7 +26,7 @@ config ZRAM_WRITEBACK
|
||||
With /sys/block/zramX/{idle,writeback}, application could ask
|
||||
idle page's writeback to the backing device to save in memory.
|
||||
|
||||
See Documentation/blockdev/zram.txt for more information.
|
||||
See Documentation/blockdev/zram.rst for more information.
|
||||
|
||||
config ZRAM_MEMORY_TRACKING
|
||||
bool "Track zRam block status"
|
||||
@ -36,4 +36,4 @@ config ZRAM_MEMORY_TRACKING
|
||||
of zRAM. Admin could see the information via
|
||||
/sys/kernel/debug/zram/zramX/block_state.
|
||||
|
||||
See Documentation/blockdev/zram.txt for more information.
|
||||
See Documentation/blockdev/zram.rst for more information.
|
||||
|
||||
@ -37,4 +37,4 @@ Commands required for testing:
|
||||
- mkfs/ mkfs.ext4
|
||||
|
||||
For more information please refer:
|
||||
kernel-source-tree/Documentation/blockdev/zram.txt
|
||||
kernel-source-tree/Documentation/blockdev/zram.rst
|
||||
|
||||
Loading…
Reference in New Issue
Block a user