docs conversion for v5.3-rc1

-----BEGIN PGP SIGNATURE-----
 
 iQIzBAABCAAdFiEE+QmuaPwR3wnBdVwACF8+vY7k4RUFAl0tpocACgkQCF8+vY7k
 4RWoxA//b/fmDXP3WPzrjjSmpyB9ml0/epKzPbT5S2j0lftqKBmet29k+PCjVrTx
 Nq2QauehY9ug5h8UMVUCmzPr95F0tSIGRoqk1vrn7z0K3q6k1SHrtvqbY1Bgb2Uk
 Qvh2YFU4fQLJg8WAbExCjxCdbdmBKQVGKTwCtM+tP5OMxwAFOmQrjGaUaKCKIIA2
 7Wzrx8CpSji+bJ3uK/d36c+4M9oDly5eaxBhoboL3BI0y+GqwiSASGwTO7BxrPOg
 0wq5IZHnqS8+bprT9xQdDOqf+UOY9U1cxE/+sqsHxblfUEx9gfLy/R+FLmJn+SS9
 Z3yLy4SqVHQMpWBjEAGodohikF60PAuTdymSC11jqFaKCUxWrIZg5xO+0blMrxPF
 7vYIexutCkaBMHBlNaNsHIqB7B/2FGGKoN7QW64hwvwJCGvF7OmJcV+R4bROGvh4
 nFuis9/Nm66Fq7I3aw37ThyZ0aWZdaQ0QJTH9ksxU/ZCz2hhMNYu/rXggrDvkS4U
 nr77ZT5Gd7nj4b110zf8+99uiGiinY6hTfzPAuTCLBhaxwrv4/xDHAhpwdEB5T4j
 8gOkxV8c0XWtL7sKqhGJvs/RRe2za0Y9XH6fyxsYfWcfuLjEvug8ouXMad9gxFWH
 DL3WnKJEMGLScei2wux4kGOwEbkR1bUf2cHJfh3GpCB/y8vgLOc=
 =smxY
 -----END PGP SIGNATURE-----

Merge tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media

Pull rst conversion of docs from Mauro Carvalho Chehab:
 "As agreed with Jon, I'm sending this big series directly to you, c/c
  him, as this series required a special care, in order to avoid
  conflicts with other trees"

* tag 'docs/v5.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/mchehab/linux-media: (77 commits)
  docs: kbuild: fix build with pdf and fix some minor issues
  docs: block: fix pdf output
  docs: arm: fix a breakage with pdf output
  docs: don't use nested tables
  docs: gpio: add sysfs interface to the admin-guide
  docs: locking: add it to the main index
  docs: add some directories to the main documentation index
  docs: add SPDX tags to new index files
  docs: add a memory-devices subdir to driver-api
  docs: phy: place documentation under driver-api
  docs: serial: move it to the driver-api
  docs: driver-api: add remaining converted dirs to it
  docs: driver-api: add xilinx driver API documentation
  docs: driver-api: add a series of orphaned documents
  docs: admin-guide: add a series of orphaned documents
  docs: cgroup-v1: add it to the admin-guide book
  docs: aoe: add it to the driver-api book
  docs: add some documentation dirs to the driver-api book
  docs: driver-model: move it to the driver-api book
  docs: lp855x-driver.rst: add it to the driver-api book
  ...
This commit is contained in:
Linus Torvalds 2019-07-16 12:21:41 -07:00
commit c309b6f242
559 changed files with 10467 additions and 7533 deletions

View File

@ -3120,7 +3120,7 @@ S: France
N: Rik van Riel
E: riel@redhat.com
W: http://www.surriel.com/
D: Linux-MM site, Documentation/sysctl/*, swap/mm readaround
D: Linux-MM site, Documentation/admin-guide/sysctl/*, swap/mm readaround
D: kswapd fixes, random kernel hacker, rmap VM,
D: nl.linux.org administrator, minor scheduler additions
S: Red Hat Boston

View File

@ -11,7 +11,7 @@ Description:
Kernel code may export it for complete or partial access.
GPIOs are identified as they are inside the kernel, using integers in
the range 0..INT_MAX. See Documentation/gpio for more information.
the range 0..INT_MAX. See Documentation/admin-guide/gpio for more information.
/sys/class/gpio
/export ... asks the kernel to export a GPIO to userspace

View File

@ -1,6 +1,6 @@
rfkill - radio frequency (RF) connector kill switch support
For details to this subsystem look at Documentation/rfkill.txt.
For details to this subsystem look at Documentation/driver-api/rfkill.rst.
What: /sys/class/rfkill/rfkill[0-9]+/claim
Date: 09-Jul-2007

View File

@ -1,6 +1,6 @@
rfkill - radio frequency (RF) connector kill switch support
For details to this subsystem look at Documentation/rfkill.txt.
For details to this subsystem look at Documentation/driver-api/rfkill.rst.
For the deprecated /sys/class/rfkill/*/claim knobs of this interface look in
Documentation/ABI/removed/sysfs-class-rfkill.

View File

@ -61,7 +61,7 @@ Date: October 2002
Contact: Linux Memory Management list <linux-mm@kvack.org>
Description:
The node's hit/miss statistics, in units of pages.
See Documentation/numastat.txt
See Documentation/admin-guide/numastat.rst
What: /sys/devices/system/node/nodeX/distance
Date: October 2002

View File

@ -29,4 +29,4 @@ Description:
17 - sectors discarded
18 - time spent discarding
For more details refer to Documentation/iostats.txt
For more details refer to Documentation/admin-guide/iostats.rst

View File

@ -15,7 +15,7 @@ Description:
9 - I/Os currently in progress
10 - time spent doing I/Os (ms)
11 - weighted time spent doing I/Os (ms)
For more details refer Documentation/iostats.txt
For more details refer Documentation/admin-guide/iostats.rst
What: /sys/block/<disk>/<part>/stat

View File

@ -45,7 +45,7 @@ Description:
- Values below -2 are rejected with -EINVAL
For more information, see
Documentation/laptops/disk-shock-protection.txt
Documentation/admin-guide/laptops/disk-shock-protection.rst
What: /sys/block/*/device/ncq_prio_enable

View File

@ -1,6 +1,6 @@
switchtec - Microsemi Switchtec PCI Switch Management Endpoint
For details on this subsystem look at Documentation/switchtec.txt.
For details on this subsystem look at Documentation/driver-api/switchtec.rst.
What: /sys/class/switchtec
Date: 05-Jan-2017

View File

@ -34,7 +34,7 @@ Description: CPU topology files that describe kernel limits related to
present: cpus that have been identified as being present in
the system.
See Documentation/cputopology.txt for more information.
See Documentation/admin-guide/cputopology.rst for more information.
What: /sys/devices/system/cpu/probe
@ -103,7 +103,7 @@ Description: CPU topology files that describe a logical CPU's relationship
thread_siblings_list: human-readable list of cpu#'s hardware
threads within the same core as cpu#
See Documentation/cputopology.txt for more information.
See Documentation/admin-guide/cputopology.rst for more information.
What: /sys/devices/system/cpu/cpuidle/current_driver

View File

@ -31,7 +31,7 @@ Description:
To control the LED display, use the following :
echo 0x0T000DDD > /sys/devices/platform/asus_laptop/
where T control the 3 letters display, and DDD the 3 digits display.
The DDD table can be found in Documentation/laptops/asus-laptop.txt
The DDD table can be found in Documentation/admin-guide/laptops/asus-laptop.rst
What: /sys/devices/platform/asus_laptop/bluetooth
Date: January 2007

View File

@ -212,7 +212,7 @@ The standard 64-bit addressing device would do something like this::
If the device only supports 32-bit addressing for descriptors in the
coherent allocations, but supports full 64-bits for streaming mappings
it would look like this:
it would look like this::
if (dma_set_mask(dev, DMA_BIT_MASK(64))) {
dev_warn(dev, "mydev: No suitable DMA available\n");

View File

@ -1,3 +1,7 @@
==================
Control Groupstats
==================
Control Groupstats is inspired by the discussion at
http://lkml.org/lkml/2007/4/11/187 and implements per cgroup statistics as
suggested by Andrew Morton in http://lkml.org/lkml/2007/4/11/263.
@ -19,9 +23,9 @@ about tasks blocked on I/O. If CONFIG_TASK_DELAY_ACCT is disabled, this
information will not be available.
To extract cgroup statistics a utility very similar to getdelays.c
has been developed, the sample output of the utility is shown below
has been developed, the sample output of the utility is shown below::
~/balbir/cgroupstats # ./getdelays -C "/sys/fs/cgroup/a"
sleeping 1, blocked 0, running 1, stopped 0, uninterruptible 0
~/balbir/cgroupstats # ./getdelays -C "/sys/fs/cgroup"
sleeping 155, blocked 0, running 1, stopped 0, uninterruptible 2
~/balbir/cgroupstats # ./getdelays -C "/sys/fs/cgroup/a"
sleeping 1, blocked 0, running 1, stopped 0, uninterruptible 0
~/balbir/cgroupstats # ./getdelays -C "/sys/fs/cgroup"
sleeping 155, blocked 0, running 1, stopped 0, uninterruptible 2

View File

@ -1,5 +1,6 @@
================
Delay accounting
----------------
================
Tasks encounter delays in execution when they wait
for some kernel resource to become available e.g. a
@ -39,7 +40,9 @@ in detail in a separate document in this directory. Taskstats returns a
generic data structure to userspace corresponding to per-pid and per-tgid
statistics. The delay accounting functionality populates specific fields of
this structure. See
include/linux/taskstats.h
for a description of the fields pertaining to delay accounting.
It will generally be in the form of counters returning the cumulative
delay seen for cpu, sync block I/O, swapin, memory reclaim etc.
@ -61,13 +64,16 @@ also serves as an example of using the taskstats interface.
Usage
-----
Compile the kernel with
Compile the kernel with::
CONFIG_TASK_DELAY_ACCT=y
CONFIG_TASKSTATS=y
Delay accounting is enabled by default at boot up.
To disable, add
To disable, add::
nodelayacct
to the kernel boot options. The rest of the instructions
below assume this has not been done.
@ -78,40 +84,43 @@ The utility also allows a given command to be
executed and the corresponding delays to be
seen.
General format of the getdelays command
General format of the getdelays command::
getdelays [-t tgid] [-p pid] [-c cmd...]
getdelays [-t tgid] [-p pid] [-c cmd...]
Get delays, since system boot, for pid 10
# ./getdelays -p 10
(output similar to next case)
Get delays, since system boot, for pid 10::
Get sum of delays, since system boot, for all pids with tgid 5
# ./getdelays -t 5
# ./getdelays -p 10
(output similar to next case)
Get sum of delays, since system boot, for all pids with tgid 5::
# ./getdelays -t 5
CPU count real total virtual total delay total
7876 92005750 100000000 24001500
IO count delay total
0 0
SWAP count delay total
0 0
RECLAIM count delay total
0 0
CPU count real total virtual total delay total
7876 92005750 100000000 24001500
IO count delay total
0 0
SWAP count delay total
0 0
RECLAIM count delay total
0 0
Get delays seen in executing a given simple command
# ./getdelays -c ls /
Get delays seen in executing a given simple command::
bin data1 data3 data5 dev home media opt root srv sys usr
boot data2 data4 data6 etc lib mnt proc sbin subdomain tmp var
# ./getdelays -c ls /
bin data1 data3 data5 dev home media opt root srv sys usr
boot data2 data4 data6 etc lib mnt proc sbin subdomain tmp var
CPU count real total virtual total delay total
CPU count real total virtual total delay total
6 4000250 4000000 0
IO count delay total
IO count delay total
0 0
SWAP count delay total
SWAP count delay total
0 0
RECLAIM count delay total
RECLAIM count delay total
0 0

View File

@ -0,0 +1,14 @@
.. SPDX-License-Identifier: GPL-2.0
==========
Accounting
==========
.. toctree::
:maxdepth: 1
cgroupstats
delay-accounting
psi
taskstats
taskstats-struct

View File

@ -35,14 +35,14 @@ Pressure interface
Pressure information for each resource is exported through the
respective file in /proc/pressure/ -- cpu, memory, and io.
The format for CPU is as such:
The format for CPU is as such::
some avg10=0.00 avg60=0.00 avg300=0.00 total=0
some avg10=0.00 avg60=0.00 avg300=0.00 total=0
and for memory and IO:
and for memory and IO::
some avg10=0.00 avg60=0.00 avg300=0.00 total=0
full avg10=0.00 avg60=0.00 avg300=0.00 total=0
some avg10=0.00 avg60=0.00 avg300=0.00 total=0
full avg10=0.00 avg60=0.00 avg300=0.00 total=0
The "some" line indicates the share of time in which at least some
tasks are stalled on a given resource.
@ -77,9 +77,9 @@ To register a trigger user has to open psi interface file under
/proc/pressure/ representing the resource to be monitored and write the
desired threshold and time window. The open file descriptor should be
used to wait for trigger events using select(), poll() or epoll().
The following format is used:
The following format is used::
<some|full> <stall amount in us> <time window in us>
<some|full> <stall amount in us> <time window in us>
For example writing "some 150000 1000000" into /proc/pressure/memory
would add 150ms threshold for partial memory stall measured within
@ -115,18 +115,20 @@ trigger is closed.
Userspace monitor usage example
===============================
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <poll.h>
#include <string.h>
#include <unistd.h>
::
/*
* Monitor memory partial stall with 1s tracking window size
* and 150ms threshold.
*/
int main() {
#include <errno.h>
#include <fcntl.h>
#include <stdio.h>
#include <poll.h>
#include <string.h>
#include <unistd.h>
/*
* Monitor memory partial stall with 1s tracking window size
* and 150ms threshold.
*/
int main() {
const char trig[] = "some 150000 1000000";
struct pollfd fds;
int n;
@ -165,7 +167,7 @@ int main() {
}
return 0;
}
}
Cgroup2 interface
=================

View File

@ -1,5 +1,6 @@
====================
The struct taskstats
--------------------
====================
This document contains an explanation of the struct taskstats fields.
@ -10,16 +11,24 @@ There are three different groups of fields in the struct taskstats:
the common fields and basic accounting fields are collected for
delivery at do_exit() of a task.
2) Delay accounting fields
These fields are placed between
/* Delay accounting fields start */
and
/* Delay accounting fields end */
These fields are placed between::
/* Delay accounting fields start */
and::
/* Delay accounting fields end */
Their values are collected if CONFIG_TASK_DELAY_ACCT is set.
3) Extended accounting fields
These fields are placed between
/* Extended accounting fields start */
and
/* Extended accounting fields end */
These fields are placed between::
/* Extended accounting fields start */
and::
/* Extended accounting fields end */
Their values are collected if CONFIG_TASK_XACCT is set.
4) Per-task and per-thread context switch count statistics
@ -31,31 +40,33 @@ There are three different groups of fields in the struct taskstats:
Future extension should add fields to the end of the taskstats struct, and
should not change the relative position of each field within the struct.
::
struct taskstats {
struct taskstats {
1) Common and basic accounting fields::
1) Common and basic accounting fields:
/* The version number of this struct. This field is always set to
* TAKSTATS_VERSION, which is defined in <linux/taskstats.h>.
* Each time the struct is changed, the value should be incremented.
*/
__u16 version;
/* The exit code of a task. */
/* The exit code of a task. */
__u32 ac_exitcode; /* Exit status */
/* The accounting flags of a task as defined in <linux/acct.h>
/* The accounting flags of a task as defined in <linux/acct.h>
* Defined values are AFORK, ASU, ACOMPAT, ACORE, and AXSIG.
*/
__u8 ac_flag; /* Record flags */
/* The value of task_nice() of a task. */
/* The value of task_nice() of a task. */
__u8 ac_nice; /* task_nice */
/* The name of the command that started this task. */
/* The name of the command that started this task. */
char ac_comm[TS_COMM_LEN]; /* Command name */
/* The scheduling discipline as set in task->policy field. */
/* The scheduling discipline as set in task->policy field. */
__u8 ac_sched; /* Scheduling discipline */
__u8 ac_pad[3];
@ -64,26 +75,27 @@ struct taskstats {
__u32 ac_pid; /* Process ID */
__u32 ac_ppid; /* Parent process ID */
/* The time when a task begins, in [secs] since 1970. */
/* The time when a task begins, in [secs] since 1970. */
__u32 ac_btime; /* Begin time [sec since 1970] */
/* The elapsed time of a task, in [usec]. */
/* The elapsed time of a task, in [usec]. */
__u64 ac_etime; /* Elapsed time [usec] */
/* The user CPU time of a task, in [usec]. */
/* The user CPU time of a task, in [usec]. */
__u64 ac_utime; /* User CPU time [usec] */
/* The system CPU time of a task, in [usec]. */
/* The system CPU time of a task, in [usec]. */
__u64 ac_stime; /* System CPU time [usec] */
/* The minor page fault count of a task, as set in task->min_flt. */
/* The minor page fault count of a task, as set in task->min_flt. */
__u64 ac_minflt; /* Minor Page Fault Count */
/* The major page fault count of a task, as set in task->maj_flt. */
__u64 ac_majflt; /* Major Page Fault Count */
2) Delay accounting fields:
2) Delay accounting fields::
/* Delay accounting fields start
*
* All values, until the comment "Delay accounting fields end" are
@ -134,7 +146,8 @@ struct taskstats {
/* version 1 ends here */
3) Extended accounting fields
3) Extended accounting fields::
/* Extended accounting fields start */
/* Accumulated RSS usage in duration of a task, in MBytes-usecs.
@ -145,15 +158,15 @@ struct taskstats {
*/
__u64 coremem; /* accumulated RSS usage in MB-usec */
/* Accumulated virtual memory usage in duration of a task.
/* Accumulated virtual memory usage in duration of a task.
* Same as acct_rss_mem1 above except that we keep track of VM usage.
*/
__u64 virtmem; /* accumulated VM usage in MB-usec */
/* High watermark of RSS usage in duration of a task, in KBytes. */
/* High watermark of RSS usage in duration of a task, in KBytes. */
__u64 hiwater_rss; /* High-watermark of RSS usage */
/* High watermark of VM usage in duration of a task, in KBytes. */
/* High watermark of VM usage in duration of a task, in KBytes. */
__u64 hiwater_vm; /* High-water virtual memory usage */
/* The following four fields are I/O statistics of a task. */
@ -164,17 +177,23 @@ struct taskstats {
/* Extended accounting fields end */
4) Per-task and per-thread statistics
4) Per-task and per-thread statistics::
__u64 nvcsw; /* Context voluntary switch counter */
__u64 nivcsw; /* Context involuntary switch counter */
5) Time accounting for SMT machines
5) Time accounting for SMT machines::
__u64 ac_utimescaled; /* utime scaled on frequency etc */
__u64 ac_stimescaled; /* stime scaled on frequency etc */
__u64 cpu_scaled_run_real_total; /* scaled cpu_run_real_total */
6) Extended delay accounting fields for memory reclaim
6) Extended delay accounting fields for memory reclaim::
/* Delay waiting for memory reclaim */
__u64 freepages_count;
__u64 freepages_delay_total;
}
::
}

View File

@ -1,5 +1,6 @@
=============================
Per-task statistics interface
-----------------------------
=============================
Taskstats is a netlink-based interface for sending per-task and
@ -65,7 +66,7 @@ taskstats.h file.
The data exchanged between user and kernel space is a netlink message belonging
to the NETLINK_GENERIC family and using the netlink attributes interface.
The messages are in the format
The messages are in the format::
+----------+- - -+-------------+-------------------+
| nlmsghdr | Pad | genlmsghdr | taskstats payload |
@ -167,15 +168,13 @@ extended and the number of cpus grows large.
To avoid losing statistics, userspace should do one or more of the following:
- increase the receive buffer sizes for the netlink sockets opened by
listeners to receive exit data.
listeners to receive exit data.
- create more listeners and reduce the number of cpus being listened to by
each listener. In the extreme case, there could be one listener for each cpu.
Users may also consider setting the cpu affinity of the listener to the subset
of cpus to which it listens, especially if they are listening to just one cpu.
each listener. In the extreme case, there could be one listener for each cpu.
Users may also consider setting the cpu affinity of the listener to the subset
of cpus to which it listens, especially if they are listening to just one cpu.
Despite these measures, if the userspace receives ENOBUFS error messages
indicated overflow of receive buffers, it should take measures to handle the
loss of data.
----

View File

@ -20,7 +20,7 @@ driver. The aoetools are on sourceforge.
http://aoetools.sourceforge.net/
The scripts in this Documentation/aoe directory are intended to
The scripts in this Documentation/admin-guide/aoe directory are intended to
document the use of the driver and are not necessary if you install
the aoetools.
@ -86,7 +86,7 @@ Using sysfs
a convenient way. Users with aoetools should use the aoe-stat
command::
root@makki root# sh Documentation/aoe/status.sh
root@makki root# sh Documentation/admin-guide/aoe/status.sh
e10.0 eth3 up
e10.1 eth3 up
e10.2 eth3 up

View File

@ -1,5 +1,3 @@
:orphan:
=======================
ATA over Ethernet (AoE)
=======================

View File

@ -11,7 +11,7 @@
# udev_rules="/etc/udev/rules.d/"
# bash# ls /etc/udev/rules.d/
# 10-wacom.rules 50-udev.rules
# bash# cp /path/to/linux/Documentation/aoe/udev.txt \
# bash# cp /path/to/linux/Documentation/admin-guide/aoe/udev.txt \
# /etc/udev/rules.d/60-aoe.rules
#

View File

Before

Width:  |  Height:  |  Size: 22 KiB

After

Width:  |  Height:  |  Size: 22 KiB

View File

Before

Width:  |  Height:  |  Size: 17 KiB

After

Width:  |  Height:  |  Size: 17 KiB

View File

@ -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 |

View File

@ -0,0 +1,30 @@
.. SPDX-License-Identifier: GPL-2.0
.. 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

View File

@ -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

View File

@ -11,4 +11,3 @@ digraph peer_states {
Unknown -> Primary [ label = "connected" ]
Unknown -> Secondary [ label = "connected" ]
}

View File

@ -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

View File

@ -0,0 +1,16 @@
.. SPDX-License-Identifier: GPL-2.0
===========================
The Linux RapidIO Subsystem
===========================
.. toctree::
:maxdepth: 1
floppy
nbd
paride
ramdisk
zram
drbd/index

View File

@ -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).

View File

@ -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/

View File

@ -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

View File

@ -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.
@ -142,44 +171,51 @@ 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.
File /sys/block/zram<id>/stat
Represents block layer statistics. Read Documentation/block/stat.txt for
Represents block layer statistics. Read Documentation/block/stat.rst for
details.
File /sys/block/zram<id>/io_stat
@ -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

View File

@ -90,9 +90,9 @@ the disk is not available then you have three options:
run a null modem to a second machine and capture the output there
using your favourite communication program. Minicom works well.
(3) Use Kdump (see Documentation/kdump/kdump.rst),
(3) Use Kdump (see Documentation/admin-guide/kdump/kdump.rst),
extract the kernel ring buffer from old memory with using dmesg
gdbmacro in Documentation/kdump/gdbmacros.txt.
gdbmacro in Documentation/admin-guide/kdump/gdbmacros.txt.
Finding the bug's location
--------------------------

View File

@ -3,7 +3,7 @@ Control Groups
==============
Written by Paul Menage <menage@google.com> based on
Documentation/cgroup-v1/cpusets.rst
Documentation/admin-guide/cgroup-v1/cpusets.rst
Original copyright statements from cpusets.txt:
@ -76,7 +76,7 @@ On their own, the only use for cgroups is for simple job
tracking. The intention is that other subsystems hook into the generic
cgroup support to provide new attributes for cgroups, such as
accounting/limiting the resources which processes in a cgroup can
access. For example, cpusets (see Documentation/cgroup-v1/cpusets.rst) allow
access. For example, cpusets (see Documentation/admin-guide/cgroup-v1/cpusets.rst) allow
you to associate a set of CPUs and a set of memory nodes with the
tasks in each cgroup.

View File

@ -49,7 +49,7 @@ hooks, beyond what is already present, required to manage dynamic
job placement on large systems.
Cpusets use the generic cgroup subsystem described in
Documentation/cgroup-v1/cgroups.rst.
Documentation/admin-guide/cgroup-v1/cgroups.rst.
Requests by a task, using the sched_setaffinity(2) system call to
include CPUs in its CPU affinity mask, and using the mbind(2) and

View File

@ -1,5 +1,3 @@
:orphan:
========================
Control Groups version 1
========================

View File

@ -10,7 +10,7 @@ Because VM is getting complex (one of reasons is memcg...), memcg's behavior
is complex. This is a document for memcg's internal behavior.
Please note that implementation details can be changed.
(*) Topics on API should be in Documentation/cgroup-v1/memory.rst)
(*) Topics on API should be in Documentation/admin-guide/cgroup-v1/memory.rst)
0. How to record usage ?
========================
@ -327,7 +327,7 @@ Under below explanation, we assume CONFIG_MEM_RES_CTRL_SWAP=y.
You can see charges have been moved by reading ``*.usage_in_bytes`` or
memory.stat of both A and B.
See 8.2 of Documentation/cgroup-v1/memory.rst to see what value should
See 8.2 of Documentation/admin-guide/cgroup-v1/memory.rst to see what value should
be written to move_charge_at_immigrate.
9.10 Memory thresholds

View File

@ -9,7 +9,7 @@ This is the authoritative documentation on the design, interface and
conventions of cgroup v2. It describes all userland-visible aspects
of cgroup including core and specific controller behaviors. All
future changes must be reflected in this document. Documentation for
v1 is available under Documentation/cgroup-v1/.
v1 is available under Documentation/admin-guide/cgroup-v1/.
.. CONTENTS
@ -1014,7 +1014,7 @@ All time durations are in microseconds.
A read-only nested-key file which exists on non-root cgroups.
Shows pressure stall information for CPU. See
Documentation/accounting/psi.txt for details.
Documentation/accounting/psi.rst for details.
Memory
@ -1355,7 +1355,7 @@ PAGE_SIZE multiple when read back.
A read-only nested-key file which exists on non-root cgroups.
Shows pressure stall information for memory. See
Documentation/accounting/psi.txt for details.
Documentation/accounting/psi.rst for details.
Usage Guidelines
@ -1498,7 +1498,7 @@ IO Interface Files
A read-only nested-key file which exists on non-root cgroups.
Shows pressure stall information for IO. See
Documentation/accounting/psi.txt for details.
Documentation/accounting/psi.rst for details.
Writeback

View File

@ -1,5 +1,3 @@
:orphan:
=============
Device Mapper
=============

View File

@ -13,7 +13,7 @@ the range specified.
The I/O statistics counters for each step-sized area of a region are
in the same format as `/sys/block/*/stat` or `/proc/diskstats` (see:
Documentation/iostats.txt). But two extra counters (12 and 13) are
Documentation/admin-guide/iostats.rst). But two extra counters (12 and 13) are
provided: total time spent reading and writing. When the histogram
argument is used, the 14th parameter is reported that represents the
histogram of latencies. All these counters may be accessed by sending
@ -151,7 +151,7 @@ Messages
The first 11 counters have the same meaning as
`/sys/block/*/stat or /proc/diskstats`.
Please refer to Documentation/iostats.txt for details.
Please refer to Documentation/admin-guide/iostats.rst for details.
1. the number of reads completed
2. the number of reads merged

View File

@ -1,4 +1,4 @@
:orphan:
.. SPDX-License-Identifier: GPL-2.0
====
gpio

View File

@ -241,7 +241,7 @@ Guest mitigation mechanisms
For further information about confining guests to a single or to a group
of cores consult the cpusets documentation:
https://www.kernel.org/doc/Documentation/cgroup-v1/cpusets.rst
https://www.kernel.org/doc/Documentation/admin-guide/cgroup-v1/cpusets.rst
.. _interrupt_isolation:

View File

@ -16,6 +16,7 @@ etc.
README
kernel-parameters
devices
sysctl/index
This section describes CPU vulnerabilities and their mitigations.
@ -38,6 +39,8 @@ problems and bugs in particular.
ramoops
dynamic-debug-howto
init
kdump/index
perf/index
This is the beginning of a section with information of interest to
application developers. Documents covering various aspects of the kernel
@ -56,11 +59,13 @@ configure specific aspects of kernel behavior to your liking.
initrd
cgroup-v2
cgroup-v1/index
serial-console
braille-console
parport
md
module-signing
rapidio
sysrq
unicode
vga-softcursor
@ -69,14 +74,37 @@ configure specific aspects of kernel behavior to your liking.
java
ras
bcache
blockdev/index
ext4
binderfs
pm/index
thunderbolt
LSM/index
mm/index
namespaces/index
perf-security
acpi/index
aoe/index
btmrvl
clearing-warn-once
cpu-load
cputopology
device-mapper/index
efi-stub
gpio/index
highuid
hw_random
iostats
kernel-per-CPU-kthreads
laptops/index
lcd-panel-cgram
ldm
lockup-watchdogs
numastat
pnp
rtc
svga
video-output
.. only:: subproject and html

Some files were not shown because too many files have changed in this diff Show More