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Merge branch 'linus' into x86/core

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This commit is contained in:
Ingo Molnar
2009-03-28 22:27:45 +01:00
parent 93394a761d 7c730ccdc1
commit 3fab191002
3171 changed files with 253006 additions and 129563 deletions
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Documentation/ABI/testing/ima_policy
+61
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@@ -0,0 +1,61 @@
What: security/ima/policy
Date: May 2008
Contact: Mimi Zohar <zohar@us.ibm.com>
Description:
The Trusted Computing Group(TCG) runtime Integrity
Measurement Architecture(IMA) maintains a list of hash
values of executables and other sensitive system files
loaded into the run-time of this system. At runtime,
the policy can be constrained based on LSM specific data.
Policies are loaded into the securityfs file ima/policy
by opening the file, writing the rules one at a time and
then closing the file. The new policy takes effect after
the file ima/policy is closed.
rule format: action [condition ...]
action: measure | dont_measure
condition:= base | lsm
base: [[func=] [mask=] [fsmagic=] [uid=]]
lsm: [[subj_user=] [subj_role=] [subj_type=]
[obj_user=] [obj_role=] [obj_type=]]
base: func:= [BPRM_CHECK][FILE_MMAP][INODE_PERMISSION]
mask:= [MAY_READ] [MAY_WRITE] [MAY_APPEND] [MAY_EXEC]
fsmagic:= hex value
uid:= decimal value
lsm: are LSM specific
default policy:
# PROC_SUPER_MAGIC
dont_measure fsmagic=0x9fa0
# SYSFS_MAGIC
dont_measure fsmagic=0x62656572
# DEBUGFS_MAGIC
dont_measure fsmagic=0x64626720
# TMPFS_MAGIC
dont_measure fsmagic=0x01021994
# SECURITYFS_MAGIC
dont_measure fsmagic=0x73636673
measure func=BPRM_CHECK
measure func=FILE_MMAP mask=MAY_EXEC
measure func=INODE_PERM mask=MAY_READ uid=0
The default policy measures all executables in bprm_check,
all files mmapped executable in file_mmap, and all files
open for read by root in inode_permission.
Examples of LSM specific definitions:
SELinux:
# SELINUX_MAGIC
dont_measure fsmagic=0xF97CFF8C
dont_measure obj_type=var_log_t
dont_measure obj_type=auditd_log_t
measure subj_user=system_u func=INODE_PERM mask=MAY_READ
measure subj_role=system_r func=INODE_PERM mask=MAY_READ
Smack:
measure subj_user=_ func=INODE_PERM mask=MAY_READ
Documentation/DocBook/Makefile
+2 -1
View File
@@ -12,7 +12,8 @@ DOCBOOKS := z8530book.xml mcabook.xml device-drivers.xml \
kernel-api.xml filesystems.xml lsm.xml usb.xml kgdb.xml \
gadget.xml libata.xml mtdnand.xml librs.xml rapidio.xml \
genericirq.xml s390-drivers.xml uio-howto.xml scsi.xml \
mac80211.xml debugobjects.xml sh.xml regulator.xml
mac80211.xml debugobjects.xml sh.xml regulator.xml \
alsa-driver-api.xml writing-an-alsa-driver.xml
###
# The build process is as follows (targets):
Documentation/sound/alsa/DocBook/alsa-driver-api.tmpl → Documentation/DocBook/alsa-driver-api.tmpl
+13 -4
View File
@@ -1,11 +1,11 @@
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
<book>
<?dbhtml filename="index.html">
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
<!-- ****************************************************** -->
<!-- Header -->
<!-- ****************************************************** -->
<book id="ALSA-Driver-API">
<bookinfo>
<title>The ALSA Driver API</title>
@@ -35,6 +35,8 @@
</bookinfo>
<toc></toc>
<chapter><title>Management of Cards and Devices</title>
<sect1><title>Card Management</title>
!Esound/core/init.c
@@ -71,6 +73,10 @@
!Esound/pci/ac97/ac97_codec.c
!Esound/pci/ac97/ac97_pcm.c
</sect1>
<sect1><title>Virtual Master Control API</title>
!Esound/core/vmaster.c
!Iinclude/sound/control.h
</sect1>
</chapter>
<chapter><title>MIDI API</title>
<sect1><title>Raw MIDI API</title>
@@ -88,6 +94,9 @@
<chapter><title>Miscellaneous Functions</title>
<sect1><title>Hardware-Dependent Devices API</title>
!Esound/core/hwdep.c
</sect1>
<sect1><title>Jack Abstraction Layer API</title>
!Esound/core/jack.c
</sect1>
<sect1><title>ISA DMA Helpers</title>
!Esound/core/isadma.c
Documentation/DocBook/genericirq.tmpl
+1
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@@ -440,6 +440,7 @@ desc->chip->end();
used in the generic IRQ layer.
</para>
!Iinclude/linux/irq.h
!Iinclude/linux/interrupt.h
</chapter>
<chapter id="pubfunctions">
Documentation/DocBook/mac80211.tmpl
+14 -4
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@@ -17,8 +17,7 @@
</authorgroup>
<copyright>
<year>2007</year>
<year>2008</year>
<year>2007-2009</year>
<holder>Johannes Berg</holder>
</copyright>
@@ -165,8 +164,8 @@ usage should require reading the full document.
!Pinclude/net/mac80211.h Frame format
</sect1>
<sect1>
<title>Alignment issues</title>
<para>TBD</para>
<title>Packet alignment</title>
!Pnet/mac80211/rx.c Packet alignment
</sect1>
<sect1>
<title>Calling into mac80211 from interrupts</title>
@@ -223,6 +222,17 @@ usage should require reading the full document.
!Finclude/net/mac80211.h ieee80211_key_flags
</chapter>
<chapter id="powersave">
<title>Powersave support</title>
!Pinclude/net/mac80211.h Powersave support
</chapter>
<chapter id="beacon-filter">
<title>Beacon filter support</title>
!Pinclude/net/mac80211.h Beacon filter support
!Finclude/net/mac80211.h ieee80211_beacon_loss
</chapter>
<chapter id="qos">
<title>Multiple queues and QoS support</title>
<para>TBD</para>
Documentation/DocBook/uio-howto.tmpl
+25 -4
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@@ -41,6 +41,13 @@ GPL version 2.
</abstract>
<revhistory>
<revision>
<revnumber>0.8</revnumber>
<date>2008-12-24</date>
<authorinitials>hjk</authorinitials>
<revremark>Added name attributes in mem and portio sysfs directories.
</revremark>
</revision>
<revision>
<revnumber>0.7</revnumber>
<date>2008-12-23</date>
@@ -303,10 +310,17 @@ interested in translating it, please email me
appear if the size of the mapping is not 0.
</para>
<para>
Each <filename>mapX/</filename> directory contains two read-only files
that show start address and size of the memory:
Each <filename>mapX/</filename> directory contains four read-only files
that show attributes of the memory:
</para>
<itemizedlist>
<listitem>
<para>
<filename>name</filename>: A string identifier for this mapping. This
is optional, the string can be empty. Drivers can set this to make it
easier for userspace to find the correct mapping.
</para>
</listitem>
<listitem>
<para>
<filename>addr</filename>: The address of memory that can be mapped.
@@ -366,10 +380,17 @@ offset = N * getpagesize();
<filename>/sys/class/uio/uioX/portio/</filename>.
</para>
<para>
Each <filename>portX/</filename> directory contains three read-only
files that show start, size, and type of the port region:
Each <filename>portX/</filename> directory contains four read-only
files that show name, start, size, and type of the port region:
</para>
<itemizedlist>
<listitem>
<para>
<filename>name</filename>: A string identifier for this port region.
The string is optional and can be empty. Drivers can set it to make it
easier for userspace to find a certain port region.
</para>
</listitem>
<listitem>
<para>
<filename>start</filename>: The first port of this region.
Documentation/sound/alsa/DocBook/writing-an-alsa-driver.tmpl → Documentation/DocBook/writing-an-alsa-driver.tmpl
+29 -23
View File
@@ -1,11 +1,11 @@
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook V4.1//EN">
<book>
<?dbhtml filename="index.html">
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE book PUBLIC "-//OASIS//DTD DocBook XML V4.1.2//EN"
"http://www.oasis-open.org/docbook/xml/4.1.2/docbookx.dtd" []>
<!-- ****************************************************** -->
<!-- Header -->
<!-- ****************************************************** -->
<book id="Writing-an-ALSA-Driver">
<bookinfo>
<title>Writing an ALSA Driver</title>
<author>
@@ -492,9 +492,9 @@
}
/* (2) */
card = snd_card_new(index[dev], id[dev], THIS_MODULE, 0);
if (card == NULL)
return -ENOMEM;
err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
if (err < 0)
return err;
/* (3) */
err = snd_mychip_create(card, pci, &chip);
@@ -590,8 +590,9 @@
<programlisting>
<![CDATA[
struct snd_card *card;
int err;
....
card = snd_card_new(index[dev], id[dev], THIS_MODULE, 0);
err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
]]>
</programlisting>
</informalexample>
@@ -809,26 +810,28 @@
<para>
As mentioned above, to create a card instance, call
<function>snd_card_new()</function>.
<function>snd_card_create()</function>.
<informalexample>
<programlisting>
<![CDATA[
struct snd_card *card;
card = snd_card_new(index, id, module, extra_size);
int err;
err = snd_card_create(index, id, module, extra_size, &card);
]]>
</programlisting>
</informalexample>
</para>
<para>
The function takes four arguments, the card-index number, the
The function takes five arguments, the card-index number, the
id string, the module pointer (usually
<constant>THIS_MODULE</constant>),
and the size of extra-data space. The last argument is used to
the size of extra-data space, and the pointer to return the
card instance. The extra_size argument is used to
allocate card-&gt;private_data for the
chip-specific data. Note that these data
are allocated by <function>snd_card_new()</function>.
are allocated by <function>snd_card_create()</function>.
</para>
</section>
@@ -915,15 +918,16 @@
</para>
<section id="card-management-chip-specific-snd-card-new">
<title>1. Allocating via <function>snd_card_new()</function>.</title>
<title>1. Allocating via <function>snd_card_create()</function>.</title>
<para>
As mentioned above, you can pass the extra-data-length
to the 4th argument of <function>snd_card_new()</function>, i.e.
to the 4th argument of <function>snd_card_create()</function>, i.e.
<informalexample>
<programlisting>
<![CDATA[
card = snd_card_new(index[dev], id[dev], THIS_MODULE, sizeof(struct mychip));
err = snd_card_create(index[dev], id[dev], THIS_MODULE,
sizeof(struct mychip), &card);
]]>
</programlisting>
</informalexample>
@@ -952,8 +956,8 @@
<para>
After allocating a card instance via
<function>snd_card_new()</function> (with
<constant>NULL</constant> on the 4th arg), call
<function>snd_card_create()</function> (with
<constant>0</constant> on the 4th arg), call
<function>kzalloc()</function>.
<informalexample>
@@ -961,7 +965,7 @@
<![CDATA[
struct snd_card *card;
struct mychip *chip;
card = snd_card_new(index[dev], id[dev], THIS_MODULE, NULL);
err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
.....
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
]]>
@@ -5750,8 +5754,9 @@ struct _snd_pcm_runtime {
....
struct snd_card *card;
struct mychip *chip;
int err;
....
card = snd_card_new(index[dev], id[dev], THIS_MODULE, NULL);
err = snd_card_create(index[dev], id[dev], THIS_MODULE, 0, &card);
....
chip = kzalloc(sizeof(*chip), GFP_KERNEL);
....
@@ -5763,7 +5768,7 @@ struct _snd_pcm_runtime {
</informalexample>
When you created the chip data with
<function>snd_card_new()</function>, it's anyway accessible
<function>snd_card_create()</function>, it's anyway accessible
via <structfield>private_data</structfield> field.
<informalexample>
@@ -5775,9 +5780,10 @@ struct _snd_pcm_runtime {
....
struct snd_card *card;
struct mychip *chip;
int err;
....
card = snd_card_new(index[dev], id[dev], THIS_MODULE,
sizeof(struct mychip));
err = snd_card_create(index[dev], id[dev], THIS_MODULE,
sizeof(struct mychip), &card);
....
chip = card->private_data;
....
Documentation/block/switching-sched.txt
-6
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@@ -35,9 +35,3 @@ noop anticipatory deadline [cfq]
# echo anticipatory > /sys/block/hda/queue/scheduler
# cat /sys/block/hda/queue/scheduler
noop [anticipatory] deadline cfq
Each io queue has a set of io scheduler tunables associated with it. These
tunables control how the io scheduler works. You can find these entries
in:
/sys/block/<device>/queue/iosched
Documentation/cpu-freq/governors.txt
+21 -3
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@@ -117,10 +117,28 @@ accessible parameters:
sampling_rate: measured in uS (10^-6 seconds), this is how often you
want the kernel to look at the CPU usage and to make decisions on
what to do about the frequency. Typically this is set to values of
around '10000' or more.
around '10000' or more. It's default value is (cmp. with users-guide.txt):
transition_latency * 1000
The lowest value you can set is:
transition_latency * 100 or it may get restricted to a value where it
makes not sense for the kernel anymore to poll that often which depends
on your HZ config variable (HZ=1000: max=20000us, HZ=250: max=5000).
Be aware that transition latency is in ns and sampling_rate is in us, so you
get the same sysfs value by default.
Sampling rate should always get adjusted considering the transition latency
To set the sampling rate 750 times as high as the transition latency
in the bash (as said, 1000 is default), do:
echo `$(($(cat cpuinfo_transition_latency) * 750 / 1000)) \
>ondemand/sampling_rate
show_sampling_rate_(min|max): the minimum and maximum sampling rates
available that you may set 'sampling_rate' to.
show_sampling_rate_(min|max): THIS INTERFACE IS DEPRECATED, DON'T USE IT.
You can use wider ranges now and the general
cpuinfo_transition_latency variable (cmp. with user-guide.txt) can be
used to obtain exactly the same info:
show_sampling_rate_min = transtition_latency * 500 / 1000
show_sampling_rate_max = transtition_latency * 500000 / 1000
(divided by 1000 is to illustrate that sampling rate is in us and
transition latency is exported ns).
up_threshold: defines what the average CPU usage between the samplings
of 'sampling_rate' needs to be for the kernel to make a decision on
Documentation/cpu-freq/user-guide.txt
+12
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@@ -152,6 +152,18 @@ cpuinfo_min_freq : this file shows the minimum operating
frequency the processor can run at(in kHz)
cpuinfo_max_freq : this file shows the maximum operating
frequency the processor can run at(in kHz)
cpuinfo_transition_latency The time it takes on this CPU to
switch between two frequencies in nano
seconds. If unknown or known to be
that high that the driver does not
work with the ondemand governor, -1
(CPUFREQ_ETERNAL) will be returned.
Using this information can be useful
to choose an appropriate polling
frequency for a kernel governor or
userspace daemon. Make sure to not
switch the frequency too often
resulting in performance loss.
scaling_driver : this file shows what cpufreq driver is
used to set the frequency on this CPU
Documentation/devices.txt
+6
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@@ -3145,6 +3145,12 @@ Your cooperation is appreciated.
1 = /dev/blockrom1 Second ROM card's translation layer interface
...
260 char OSD (Object-based-device) SCSI Device
0 = /dev/osd0 First OSD Device
1 = /dev/osd1 Second OSD Device
...
255 = /dev/osd255 256th OSD Device
**** ADDITIONAL /dev DIRECTORY ENTRIES
This section details additional entries that should or may exist in
Documentation/dontdiff
-1
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@@ -62,7 +62,6 @@ aic7*reg_print.c*
aic7*seq.h*
aicasm
aicdb.h*
asm
asm-offsets.h
asm_offsets.h
autoconf.h*
Documentation/dynamic-debug-howto.txt
+240
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@@ -0,0 +1,240 @@
Introduction
============
This document describes how to use the dynamic debug (ddebug) feature.
Dynamic debug is designed to allow you to dynamically enable/disable kernel
code to obtain additional kernel information. Currently, if
CONFIG_DYNAMIC_DEBUG is set, then all pr_debug()/dev_debug() calls can be
dynamically enabled per-callsite.
Dynamic debug has even more useful features:
* Simple query language allows turning on and off debugging statements by
matching any combination of:
- source filename
- function name
- line number (including ranges of line numbers)
- module name
- format string
* Provides a debugfs control file: <debugfs>/dynamic_debug/control which can be
read to display the complete list of known debug statements, to help guide you
Controlling dynamic debug Behaviour
===============================
The behaviour of pr_debug()/dev_debug()s are controlled via writing to a
control file in the 'debugfs' filesystem. Thus, you must first mount the debugfs
filesystem, in order to make use of this feature. Subsequently, we refer to the
control file as: <debugfs>/dynamic_debug/control. For example, if you want to
enable printing from source file 'svcsock.c', line 1603 you simply do:
nullarbor:~ # echo 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
If you make a mistake with the syntax, the write will fail thus:
nullarbor:~ # echo 'file svcsock.c wtf 1 +p' >
<debugfs>/dynamic_debug/control
-bash: echo: write error: Invalid argument
Viewing Dynamic Debug Behaviour
===========================
You can view the currently configured behaviour of all the debug statements
via:
nullarbor:~ # cat <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:323 [svcxprt_rdma]svc_rdma_cleanup - "SVCRDMA Module Removed, deregister RPC RDMA transport\012"
/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:341 [svcxprt_rdma]svc_rdma_init - "\011max_inline : %d\012"
/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:340 [svcxprt_rdma]svc_rdma_init - "\011sq_depth : %d\012"
/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svc_rdma.c:338 [svcxprt_rdma]svc_rdma_init - "\011max_requests : %d\012"
...
You can also apply standard Unix text manipulation filters to this
data, e.g.
nullarbor:~ # grep -i rdma <debugfs>/dynamic_debug/control | wc -l
62
nullarbor:~ # grep -i tcp <debugfs>/dynamic_debug/control | wc -l
42
Note in particular that the third column shows the enabled behaviour
flags for each debug statement callsite (see below for definitions of the
flags). The default value, no extra behaviour enabled, is "-". So
you can view all the debug statement callsites with any non-default flags:
nullarbor:~ # awk '$3 != "-"' <debugfs>/dynamic_debug/control
# filename:lineno [module]function flags format
/usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c:1603 [sunrpc]svc_send p "svc_process: st_sendto returned %d\012"
Command Language Reference
==========================
At the lexical level, a command comprises a sequence of words separated
by whitespace characters. Note that newlines are treated as word
separators and do *not* end a command or allow multiple commands to
be done together. So these are all equivalent:
nullarbor:~ # echo -c 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
nullarbor:~ # echo -c ' file svcsock.c line 1603 +p ' >
<debugfs>/dynamic_debug/control
nullarbor:~ # echo -c 'file svcsock.c\nline 1603 +p' >
<debugfs>/dynamic_debug/control
nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
Commands are bounded by a write() system call. If you want to do
multiple commands you need to do a separate "echo" for each, like:
nullarbor:~ # echo 'file svcsock.c line 1603 +p' > /proc/dprintk ;\
> echo 'file svcsock.c line 1563 +p' > /proc/dprintk
or even like:
nullarbor:~ # (
> echo 'file svcsock.c line 1603 +p' ;\
> echo 'file svcsock.c line 1563 +p' ;\
> ) > /proc/dprintk
At the syntactical level, a command comprises a sequence of match
specifications, followed by a flags change specification.
command ::= match-spec* flags-spec
The match-spec's are used to choose a subset of the known dprintk()
callsites to which to apply the flags-spec. Think of them as a query
with implicit ANDs between each pair. Note that an empty list of
match-specs is possible, but is not very useful because it will not
match any debug statement callsites.
A match specification comprises a keyword, which controls the attribute
of the callsite to be compared, and a value to compare against. Possible
keywords are:
match-spec ::= 'func' string |
'file' string |
'module' string |
'format' string |
'line' line-range
line-range ::= lineno |
'-'lineno |
lineno'-' |
lineno'-'lineno
// Note: line-range cannot contain space, e.g.
// "1-30" is valid range but "1 - 30" is not.
lineno ::= unsigned-int
The meanings of each keyword are:
func
The given string is compared against the function name
of each callsite. Example:
func svc_tcp_accept
file
The given string is compared against either the full
pathname or the basename of the source file of each
callsite. Examples:
file svcsock.c
file /usr/src/packages/BUILD/sgi-enhancednfs-1.4/default/net/sunrpc/svcsock.c
module
The given string is compared against the module name
of each callsite. The module name is the string as
seen in "lsmod", i.e. without the directory or the .ko
suffix and with '-' changed to '_'. Examples:
module sunrpc
module nfsd
format
The given string is searched for in the dynamic debug format
string. Note that the string does not need to match the
entire format, only some part. Whitespace and other
special characters can be escaped using C octal character
escape \ooo notation, e.g. the space character is \040.
Alternatively, the string can be enclosed in double quote
characters (") or single quote characters (').
Examples:
format svcrdma: // many of the NFS/RDMA server dprintks
format readahead // some dprintks in the readahead cache
format nfsd:\040SETATTR // one way to match a format with whitespace
format "nfsd: SETATTR" // a neater way to match a format with whitespace
format 'nfsd: SETATTR' // yet another way to match a format with whitespace
line
The given line number or range of line numbers is compared
against the line number of each dprintk() callsite. A single
line number matches the callsite line number exactly. A
range of line numbers matches any callsite between the first
and last line number inclusive. An empty first number means
the first line in the file, an empty line number means the
last number in the file. Examples:
line 1603 // exactly line 1603
line 1600-1605 // the six lines from line 1600 to line 1605
line -1605 // the 1605 lines from line 1 to line 1605
line 1600- // all lines from line 1600 to the end of the file
The flags specification comprises a change operation followed
by one or more flag characters. The change operation is one
of the characters:
-
remove the given flags
+
add the given flags
=
set the flags to the given flags
The flags are:
p
Causes a printk() message to be emitted to dmesg
Note the regexp ^[-+=][scp]+$ matches a flags specification.
Note also that there is no convenient syntax to remove all
the flags at once, you need to use "-psc".
Examples
========
// enable the message at line 1603 of file svcsock.c
nullarbor:~ # echo -n 'file svcsock.c line 1603 +p' >
<debugfs>/dynamic_debug/control
// enable all the messages in file svcsock.c
nullarbor:~ # echo -n 'file svcsock.c +p' >
<debugfs>/dynamic_debug/control
// enable all the messages in the NFS server module
nullarbor:~ # echo -n 'module nfsd +p' >
<debugfs>/dynamic_debug/control
// enable all 12 messages in the function svc_process()
nullarbor:~ # echo -n 'func svc_process +p' >
<debugfs>/dynamic_debug/control
// disable all 12 messages in the function svc_process()
nullarbor:~ # echo -n 'func svc_process -p' >
<debugfs>/dynamic_debug/control
// enable messages for NFS calls READ, READLINK, READDIR and READDIR+.
nullarbor:~ # echo -n 'format "nfsd: READ" +p' >
<debugfs>/dynamic_debug/control
Documentation/feature-removal-schedule.txt
+52 -6
View File
@@ -6,20 +6,47 @@ be removed from this file.
---------------------------
What: old static regulatory information and ieee80211_regdom module parameter
When: 2.6.29
What: The ieee80211_regdom module parameter
When: March 2010 / desktop catchup
Why: This was inherited by the CONFIG_WIRELESS_OLD_REGULATORY code,
and currently serves as an option for users to define an
ISO / IEC 3166 alpha2 code for the country they are currently
present in. Although there are userspace API replacements for this
through nl80211 distributions haven't yet caught up with implementing
decent alternatives through standard GUIs. Although available as an
option through iw or wpa_supplicant its just a matter of time before
distributions pick up good GUI options for this. The ideal solution
would actually consist of intelligent designs which would do this for
the user automatically even when travelling through different countries.
Until then we leave this module parameter as a compromise.
When userspace improves with reasonable widely-available alternatives for
this we will no longer need this module parameter. This entry hopes that
by the super-futuristically looking date of "March 2010" we will have
such replacements widely available.
Who: Luis R. Rodriguez <lrodriguez@atheros.com>
---------------------------
What: CONFIG_WIRELESS_OLD_REGULATORY - old static regulatory information
When: March 2010 / desktop catchup
Why: The old regulatory infrastructure has been replaced with a new one
which does not require statically defined regulatory domains. We do
not want to keep static regulatory domains in the kernel due to the
the dynamic nature of regulatory law and localization. We kept around
the old static definitions for the regulatory domains of:
* US
* JP
* EU
and used by default the US when CONFIG_WIRELESS_OLD_REGULATORY was
set. We also kept around the ieee80211_regdom module parameter in case
some applications were relying on it. Changing regulatory domains
can now be done instead by using nl80211, as is done with iw.
set. We will remove this option once the standard Linux desktop catches
up with the new userspace APIs we have implemented.
Who: Luis R. Rodriguez <lrodriguez@atheros.com>
---------------------------
@@ -229,7 +256,9 @@ Who: Jan Engelhardt <jengelh@computergmbh.de>
---------------------------
What: b43 support for firmware revision < 410
When: July 2008
When: The schedule was July 2008, but it was decided that we are going to keep the
code as long as there are no major maintanance headaches.
So it _could_ be removed _any_ time now, if it conflicts with something new.
Why: The support code for the old firmware hurts code readability/maintainability
and slightly hurts runtime performance. Bugfixes for the old firmware
are not provided by Broadcom anymore.
@@ -344,3 +373,20 @@ Why: See commits 129f8ae9b1b5be94517da76009ea956e89104ce8 and
Removal is subject to fixing any remaining bugs in ACPI which may
cause the thermal throttling not to happen at the right time.
Who: Dave Jones <davej@redhat.com>, Matthew Garrett <mjg@redhat.com>
-----------------------------
What: __do_IRQ all in one fits nothing interrupt handler
When: 2.6.32
Why: __do_IRQ was kept for easy migration to the type flow handlers.
More than two years of migration time is enough.
Who: Thomas Gleixner <tglx@linutronix.de>
-----------------------------
What: obsolete generic irq defines and typedefs
When: 2.6.30
Why: The defines and typedefs (hw_interrupt_type, no_irq_type, irq_desc_t)
have been kept around for migration reasons. After more than two years
it's time to remove them finally
Who: Thomas Gleixner <tglx@linutronix.de>
Documentation/filesystems/Locking
+5 -2
View File
@@ -437,8 +437,11 @@ grab BKL for cases when we close a file that had been opened r/w, but that
can and should be done using the internal locking with smaller critical areas).
Current worst offender is ext2_get_block()...
->fasync() is a mess. This area needs a big cleanup and that will probably
affect locking.
->fasync() is called without BKL protection, and is responsible for
maintaining the FASYNC bit in filp->f_flags. Most instances call
fasync_helper(), which does that maintenance, so it's not normally
something one needs to worry about. Return values > 0 will be mapped to
zero in the VFS layer.
->readdir() and ->ioctl() on directories must be changed. Ideally we would
move ->readdir() to inode_operations and use a separate method for directory
Documentation/kernel-parameters.txt
+16 -6
View File
@@ -44,6 +44,7 @@ parameter is applicable:
FB The frame buffer device is enabled.
HW Appropriate hardware is enabled.
IA-64 IA-64 architecture is enabled.
IMA Integrity measurement architecture is enabled.
IOSCHED More than one I/O scheduler is enabled.
IP_PNP IP DHCP, BOOTP, or RARP is enabled.
ISAPNP ISA PnP code is enabled.
@@ -492,10 +493,12 @@ and is between 256 and 4096 characters. It is defined in the file
Default: 64
hpet= [X86-32,HPET] option to control HPET usage
Format: { enable (default) | disable | force }
Format: { enable (default) | disable | force |
verbose }
disable: disable HPET and use PIT instead
force: allow force enabled of undocumented chips (ICH4,
VIA, nVidia)
verbose: show contents of HPET registers during setup
com20020= [HW,NET] ARCnet - COM20020 chipset
Format:
@@ -829,6 +832,9 @@ and is between 256 and 4096 characters. It is defined in the file
hvc_iucv= [S390] Number of z/VM IUCV hypervisor console (HVC)
terminal devices. Valid values: 0..8
hvc_iucv_allow= [S390] Comma-separated list of z/VM user IDs.
If specified, z/VM IUCV HVC accepts connections
from listed z/VM user IDs only.
i8042.debug [HW] Toggle i8042 debug mode
i8042.direct [HW] Put keyboard port into non-translated mode
@@ -902,6 +908,15 @@ and is between 256 and 4096 characters. It is defined in the file
ihash_entries= [KNL]
Set number of hash buckets for inode cache.
ima_audit= [IMA]
Format: { "0" | "1" }
0 -- integrity auditing messages. (Default)
1 -- enable informational integrity auditing messages.
ima_hash= [IMA]
Formt: { "sha1" | "md5" }
default: "sha1"
in2000= [HW,SCSI]
See header of drivers/scsi/in2000.c.
@@ -1821,11 +1836,6 @@ and is between 256 and 4096 characters. It is defined in the file
autoconfiguration.
Ranges are in pairs (memory base and size).
dynamic_printk Enables pr_debug()/dev_dbg() calls if
CONFIG_DYNAMIC_PRINTK_DEBUG has been enabled.
These can also be switched on/off via
<debugfs>/dynamic_printk/modules
print-fatal-signals=
[KNL] debug: print fatal signals
print-fatal-signals=1: print segfault info to
Documentation/networking/dccp.txt
+2 -1
View File
@@ -141,7 +141,8 @@ rx_ccid = 2
Default CCID for the receiver-sender half-connection; see tx_ccid.
seq_window = 100
The initial sequence window (sec. 7.5.2).
The initial sequence window (sec. 7.5.2) of the sender. This influences
the local ackno validity and the remote seqno validity windows (7.5.1).
tx_qlen = 5
The size of the transmit buffer in packets. A value of 0 corresponds
Documentation/networking/ip-sysctl.txt
+81 -67
View File
@@ -2,7 +2,7 @@
ip_forward - BOOLEAN
0 - disabled (default)
not 0 - enabled
not 0 - enabled
Forward Packets between interfaces.
@@ -36,49 +36,49 @@ rt_cache_rebuild_count - INTEGER
IP Fragmentation:
ipfrag_high_thresh - INTEGER
Maximum memory used to reassemble IP fragments. When
Maximum memory used to reassemble IP fragments. When
ipfrag_high_thresh bytes of memory is allocated for this purpose,
the fragment handler will toss packets until ipfrag_low_thresh
is reached.
ipfrag_low_thresh - INTEGER
See ipfrag_high_thresh
See ipfrag_high_thresh
ipfrag_time - INTEGER
Time in seconds to keep an IP fragment in memory.
Time in seconds to keep an IP fragment in memory.
ipfrag_secret_interval - INTEGER
Regeneration interval (in seconds) of the hash secret (or lifetime
Regeneration interval (in seconds) of the hash secret (or lifetime
for the hash secret) for IP fragments.
Default: 600
ipfrag_max_dist - INTEGER
ipfrag_max_dist is a non-negative integer value which defines the
maximum "disorder" which is allowed among fragments which share a
common IP source address. Note that reordering of packets is
not unusual, but if a large number of fragments arrive from a source
IP address while a particular fragment queue remains incomplete, it
probably indicates that one or more fragments belonging to that queue
have been lost. When ipfrag_max_dist is positive, an additional check
is done on fragments before they are added to a reassembly queue - if
ipfrag_max_dist (or more) fragments have arrived from a particular IP
address between additions to any IP fragment queue using that source
address, it's presumed that one or more fragments in the queue are
lost. The existing fragment queue will be dropped, and a new one
ipfrag_max_dist is a non-negative integer value which defines the
maximum "disorder" which is allowed among fragments which share a
common IP source address. Note that reordering of packets is
not unusual, but if a large number of fragments arrive from a source
IP address while a particular fragment queue remains incomplete, it
probably indicates that one or more fragments belonging to that queue
have been lost. When ipfrag_max_dist is positive, an additional check
is done on fragments before they are added to a reassembly queue - if
ipfrag_max_dist (or more) fragments have arrived from a particular IP
address between additions to any IP fragment queue using that source
address, it's presumed that one or more fragments in the queue are
lost. The existing fragment queue will be dropped, and a new one
started. An ipfrag_max_dist value of zero disables this check.
Using a very small value, e.g. 1 or 2, for ipfrag_max_dist can
result in unnecessarily dropping fragment queues when normal
reordering of packets occurs, which could lead to poor application
performance. Using a very large value, e.g. 50000, increases the
likelihood of incorrectly reassembling IP fragments that originate
reordering of packets occurs, which could lead to poor application
performance. Using a very large value, e.g. 50000, increases the
likelihood of incorrectly reassembling IP fragments that originate
from different IP datagrams, which could result in data corruption.
Default: 64
INET peer storage:
inet_peer_threshold - INTEGER
The approximate size of the storage. Starting from this threshold
The approximate size of the storage. Starting from this threshold
entries will be thrown aggressively. This threshold also determines
entries' time-to-live and time intervals between garbage collection
passes. More entries, less time-to-live, less GC interval.
@@ -105,7 +105,7 @@ inet_peer_gc_maxtime - INTEGER
in effect under low (or absent) memory pressure on the pool.
Measured in seconds.
TCP variables:
TCP variables:
somaxconn - INTEGER
Limit of socket listen() backlog, known in userspace as SOMAXCONN.
@@ -310,7 +310,7 @@ tcp_orphan_retries - INTEGER
tcp_reordering - INTEGER
Maximal reordering of packets in a TCP stream.
Default: 3
Default: 3
tcp_retrans_collapse - BOOLEAN
Bug-to-bug compatibility with some broken printers.
@@ -521,7 +521,7 @@ IP Variables:
ip_local_port_range - 2 INTEGERS
Defines the local port range that is used by TCP and UDP to
choose the local port. The first number is the first, the
choose the local port. The first number is the first, the
second the last local port number. Default value depends on
amount of memory available on the system:
> 128Mb 32768-61000
@@ -594,12 +594,12 @@ icmp_errors_use_inbound_ifaddr - BOOLEAN
If zero, icmp error messages are sent with the primary address of
the exiting interface.
If non-zero, the message will be sent with the primary address of
the interface that received the packet that caused the icmp error.
This is the behaviour network many administrators will expect from
a router. And it can make debugging complicated network layouts
much easier.
much easier.
Note that if no primary address exists for the interface selected,
then the primary address of the first non-loopback interface that
@@ -611,7 +611,7 @@ igmp_max_memberships - INTEGER
Change the maximum number of multicast groups we can subscribe to.
Default: 20
conf/interface/* changes special settings per interface (where "interface" is
conf/interface/* changes special settings per interface (where "interface" is
the name of your network interface)
conf/all/* is special, changes the settings for all interfaces
@@ -625,11 +625,11 @@ log_martians - BOOLEAN
accept_redirects - BOOLEAN
Accept ICMP redirect messages.
accept_redirects for the interface will be enabled if:
- both conf/{all,interface}/accept_redirects are TRUE in the case forwarding
for the interface is enabled
- both conf/{all,interface}/accept_redirects are TRUE in the case
forwarding for the interface is enabled
or
- at least one of conf/{all,interface}/accept_redirects is TRUE in the case
forwarding for the interface is disabled
- at least one of conf/{all,interface}/accept_redirects is TRUE in the
case forwarding for the interface is disabled
accept_redirects for the interface will be disabled otherwise
default TRUE (host)
FALSE (router)
@@ -640,8 +640,8 @@ forwarding - BOOLEAN
mc_forwarding - BOOLEAN
Do multicast routing. The kernel needs to be compiled with CONFIG_MROUTE
and a multicast routing daemon is required.
conf/all/mc_forwarding must also be set to TRUE to enable multicast routing
for the interface
conf/all/mc_forwarding must also be set to TRUE to enable multicast
routing for the interface
medium_id - INTEGER
Integer value used to differentiate the devices by the medium they
@@ -649,7 +649,7 @@ medium_id - INTEGER
the broadcast packets are received only on one of them.
The default value 0 means that the device is the only interface
to its medium, value of -1 means that medium is not known.
Currently, it is used to change the proxy_arp behavior:
the proxy_arp feature is enabled for packets forwarded between
two devices attached to different media.
@@ -699,16 +699,22 @@ accept_source_route - BOOLEAN
default TRUE (router)
FALSE (host)
rp_filter - BOOLEAN
1 - do source validation by reversed path, as specified in RFC1812
Recommended option for single homed hosts and stub network
routers. Could cause troubles for complicated (not loop free)
networks running a slow unreliable protocol (sort of RIP),
or using static routes.
rp_filter - INTEGER
0 - No source validation.
1 - Strict mode as defined in RFC3704 Strict Reverse Path
Each incoming packet is tested against the FIB and if the interface
is not the best reverse path the packet check will fail.
By default failed packets are discarded.
2 - Loose mode as defined in RFC3704 Loose Reverse Path
Each incoming packet's source address is also tested against the FIB
and if the source address is not reachable via any interface
the packet check will fail.
conf/all/rp_filter must also be set to TRUE to do source validation
Current recommended practice in RFC3704 is to enable strict mode
to prevent IP spoofing from DDos attacks. If using asymmetric routing
or other complicated routing, then loose mode is recommended.
conf/all/rp_filter must also be set to non-zero to do source validation
on the interface
Default value is 0. Note that some distributions enable it
@@ -782,6 +788,12 @@ arp_ignore - INTEGER
The max value from conf/{all,interface}/arp_ignore is used
when ARP request is received on the {interface}
arp_notify - BOOLEAN
Define mode for notification of address and device changes.
0 - (default): do nothing
1 - Generate gratuitous arp replies when device is brought up
or hardware address changes.
arp_accept - BOOLEAN
Define behavior when gratuitous arp replies are received:
0 - drop gratuitous arp frames
@@ -823,7 +835,7 @@ apply to IPv6 [XXX?].
bindv6only - BOOLEAN
Default value for IPV6_V6ONLY socket option,
which restricts use of the IPv6 socket to IPv6 communication
which restricts use of the IPv6 socket to IPv6 communication
only.
TRUE: disable IPv4-mapped address feature
FALSE: enable IPv4-mapped address feature
@@ -833,19 +845,19 @@ bindv6only - BOOLEAN
IPv6 Fragmentation:
ip6frag_high_thresh - INTEGER
Maximum memory used to reassemble IPv6 fragments. When
Maximum memory used to reassemble IPv6 fragments. When
ip6frag_high_thresh bytes of memory is allocated for this purpose,
the fragment handler will toss packets until ip6frag_low_thresh
is reached.
ip6frag_low_thresh - INTEGER
See ip6frag_high_thresh
See ip6frag_high_thresh
ip6frag_time - INTEGER
Time in seconds to keep an IPv6 fragment in memory.
ip6frag_secret_interval - INTEGER
Regeneration interval (in seconds) of the hash secret (or lifetime
Regeneration interval (in seconds) of the hash secret (or lifetime
for the hash secret) for IPv6 fragments.
Default: 600
@@ -854,17 +866,17 @@ conf/default/*:
conf/all/*:
Change all the interface-specific settings.
Change all the interface-specific settings.
[XXX: Other special features than forwarding?]
conf/all/forwarding - BOOLEAN
Enable global IPv6 forwarding between all interfaces.
Enable global IPv6 forwarding between all interfaces.
IPv4 and IPv6 work differently here; e.g. netfilter must be used
IPv4 and IPv6 work differently here; e.g. netfilter must be used
to control which interfaces may forward packets and which not.
This also sets all interfaces' Host/Router setting
This also sets all interfaces' Host/Router setting
'forwarding' to the specified value. See below for details.
This referred to as global forwarding.
@@ -875,12 +887,12 @@ proxy_ndp - BOOLEAN
conf/interface/*:
Change special settings per interface.
The functional behaviour for certain settings is different
The functional behaviour for certain settings is different
depending on whether local forwarding is enabled or not.
accept_ra - BOOLEAN
Accept Router Advertisements; autoconfigure using them.
Functional default: enabled if local forwarding is disabled.
disabled if local forwarding is enabled.
@@ -926,7 +938,7 @@ accept_source_route - INTEGER
Default: 0
autoconf - BOOLEAN
Autoconfigure addresses using Prefix Information in Router
Autoconfigure addresses using Prefix Information in Router
Advertisements.
Functional default: enabled if accept_ra_pinfo is enabled.
@@ -935,11 +947,11 @@ autoconf - BOOLEAN
dad_transmits - INTEGER
The amount of Duplicate Address Detection probes to send.
Default: 1
forwarding - BOOLEAN
Configure interface-specific Host/Router behaviour.
Note: It is recommended to have the same setting on all
forwarding - BOOLEAN
Configure interface-specific Host/Router behaviour.
Note: It is recommended to have the same setting on all
interfaces; mixed router/host scenarios are rather uncommon.
FALSE:
@@ -948,13 +960,13 @@ forwarding - BOOLEAN
1. IsRouter flag is not set in Neighbour Advertisements.
2. Router Solicitations are being sent when necessary.
3. If accept_ra is TRUE (default), accept Router
3. If accept_ra is TRUE (default), accept Router
Advertisements (and do autoconfiguration).
4. If accept_redirects is TRUE (default), accept Redirects.
TRUE:
If local forwarding is enabled, Router behaviour is assumed.
If local forwarding is enabled, Router behaviour is assumed.
This means exactly the reverse from the above:
1. IsRouter flag is set in Neighbour Advertisements.
@@ -989,7 +1001,7 @@ router_solicitation_interval - INTEGER
Default: 4
router_solicitations - INTEGER
Number of Router Solicitations to send until assuming no
Number of Router Solicitations to send until assuming no
routers are present.
Default: 3
@@ -1013,11 +1025,11 @@ temp_prefered_lft - INTEGER
max_desync_factor - INTEGER
Maximum value for DESYNC_FACTOR, which is a random value
that ensures that clients don't synchronize with each
that ensures that clients don't synchronize with each
other and generate new addresses at exactly the same time.
value is in seconds.
Default: 600
regen_max_retry - INTEGER
Number of attempts before give up attempting to generate
valid temporary addresses.
@@ -1025,13 +1037,15 @@ regen_max_retry - INTEGER
max_addresses - INTEGER
Number of maximum addresses per interface. 0 disables limitation.
It is recommended not set too large value (or 0) because it would
be too easy way to crash kernel to allow to create too much of
It is recommended not set too large value (or 0) because it would
be too easy way to crash kernel to allow to create too much of
autoconfigured addresses.
Default: 16
disable_ipv6 - BOOLEAN
Disable IPv6 operation.
Disable IPv6 operation. If accept_dad is set to 2, this value
will be dynamically set to TRUE if DAD fails for the link-local
address.
Default: FALSE (enable IPv6 operation)
accept_dad - INTEGER
Documentation/networking/ixgbe.txt
+199
View File
@@ -0,0 +1,199 @@
Linux Base Driver for 10 Gigabit PCI Express Intel(R) Network Connection
========================================================================
March 10, 2009
Contents
========
- In This Release
- Identifying Your Adapter
- Building and Installation
- Additional Configurations
- Support
In This Release
===============
This file describes the ixgbe Linux Base Driver for the 10 Gigabit PCI
Express Intel(R) Network Connection. This driver includes support for
Itanium(R)2-based systems.
For questions related to hardware requirements, refer to the documentation
supplied with your 10 Gigabit adapter. All hardware requirements listed apply
to use with Linux.
The following features are available in this kernel:
- Native VLANs
- Channel Bonding (teaming)
- SNMP
- Generic Receive Offload
- Data Center Bridging
Channel Bonding documentation can be found in the Linux kernel source:
/Documentation/networking/bonding.txt
Ethtool, lspci, and ifconfig can be used to display device and driver
specific information.
Identifying Your Adapter
========================
This driver supports devices based on the 82598 controller and the 82599
controller.
For specific information on identifying which adapter you have, please visit:
http://support.intel.com/support/network/sb/CS-008441.htm
Building and Installation
=========================
select m for "Intel(R) 10GbE PCI Express adapters support" located at:
Location:
-> Device Drivers
-> Network device support (NETDEVICES [=y])
-> Ethernet (10000 Mbit) (NETDEV_10000 [=y])
1. make modules & make modules_install
2. Load the module:
# modprobe ixgbe
The insmod command can be used if the full
path to the driver module is specified. For example:
insmod /lib/modules/<KERNEL VERSION>/kernel/drivers/net/ixgbe/ixgbe.ko
With 2.6 based kernels also make sure that older ixgbe drivers are
removed from the kernel, before loading the new module:
rmmod ixgbe; modprobe ixgbe
3. Assign an IP address to the interface by entering the following, where
x is the interface number:
ifconfig ethx <IP_address>
4. Verify that the interface works. Enter the following, where <IP_address>
is the IP address for another machine on the same subnet as the interface
that is being tested:
ping <IP_address>
Additional Configurations
=========================
Viewing Link Messages
---------------------
Link messages will not be displayed to the console if the distribution is
restricting system messages. In order to see network driver link messages on
your console, set dmesg to eight by entering the following:
dmesg -n 8
NOTE: This setting is not saved across reboots.
Jumbo Frames
------------
The driver supports Jumbo Frames for all adapters. Jumbo Frames support is
enabled by changing the MTU to a value larger than the default of 1500.
The maximum value for the MTU is 16110. Use the ifconfig command to
increase the MTU size. For example:
ifconfig ethx mtu 9000 up
The maximum MTU setting for Jumbo Frames is 16110. This value coincides
with the maximum Jumbo Frames size of 16128.
Generic Receive Offload, aka GRO
--------------------------------
The driver supports the in-kernel software implementation of GRO. GRO has
shown that by coalescing Rx traffic into larger chunks of data, CPU
utilization can be significantly reduced when under large Rx load. GRO is an
evolution of the previously-used LRO interface. GRO is able to coalesce
other protocols besides TCP. It's also safe to use with configurations that
are problematic for LRO, namely bridging and iSCSI.
GRO is enabled by default in the driver. Future versions of ethtool will
support disabling and re-enabling GRO on the fly.
Data Center Bridging, aka DCB
-----------------------------
DCB is a configuration Quality of Service implementation in hardware.
It uses the VLAN priority tag (802.1p) to filter traffic. That means
that there are 8 different priorities that traffic can be filtered into.
It also enables priority flow control which can limit or eliminate the
number of dropped packets during network stress. Bandwidth can be
allocated to each of these priorities, which is enforced at the hardware
level.
To enable DCB support in ixgbe, you must enable the DCB netlink layer to
allow the userspace tools (see below) to communicate with the driver.
This can be found in the kernel configuration here:
-> Networking support
-> Networking options
-> Data Center Bridging support
Once this is selected, DCB support must be selected for ixgbe. This can
be found here:
-> Device Drivers
-> Network device support (NETDEVICES [=y])
-> Ethernet (10000 Mbit) (NETDEV_10000 [=y])
-> Intel(R) 10GbE PCI Express adapters support
-> Data Center Bridging (DCB) Support
After these options are selected, you must rebuild your kernel and your
modules.
In order to use DCB, userspace tools must be downloaded and installed.
The dcbd tools can be found at:
http://e1000.sf.net
Ethtool
-------
The driver utilizes the ethtool interface for driver configuration and
diagnostics, as well as displaying statistical information. Ethtool
version 3.0 or later is required for this functionality.
The latest release of ethtool can be found from
http://sourceforge.net/projects/gkernel.
NAPI
----
NAPI (Rx polling mode) is supported in the ixgbe driver. NAPI is enabled
by default in the driver.
See www.cyberus.ca/~hadi/usenix-paper.tgz for more information on NAPI.
Support
=======
For general information, go to the Intel support website at:
http://support.intel.com
or the Intel Wired Networking project hosted by Sourceforge at:
http://e1000.sourceforge.net
If an issue is identified with the released source code on the supported
kernel with a supported adapter, email the specific information related
to the issue to e1000-devel@lists.sf.net
Documentation/networking/rds.txt
+356
View File
@@ -0,0 +1,356 @@
Overview
========
This readme tries to provide some background on the hows and whys of RDS,
and will hopefully help you find your way around the code.
In addition, please see this email about RDS origins:
http://oss.oracle.com/pipermail/rds-devel/2007-November/000228.html
RDS Architecture
================
RDS provides reliable, ordered datagram delivery by using a single
reliable connection between any two nodes in the cluster. This allows
applications to use a single socket to talk to any other process in the
cluster - so in a cluster with N processes you need N sockets, in contrast
to N*N if you use a connection-oriented socket transport like TCP.
RDS is not Infiniband-specific; it was designed to support different
transports. The current implementation used to support RDS over TCP as well
as IB. Work is in progress to support RDS over iWARP, and using DCE to
guarantee no dropped packets on Ethernet, it may be possible to use RDS over
UDP in the future.
The high-level semantics of RDS from the application's point of view are
* Addressing
RDS uses IPv4 addresses and 16bit port numbers to identify
the end point of a connection. All socket operations that involve
passing addresses between kernel and user space generally
use a struct sockaddr_in.
The fact that IPv4 addresses are used does not mean the underlying
transport has to be IP-based. In fact, RDS over IB uses a
reliable IB connection; the IP address is used exclusively to
locate the remote node's GID (by ARPing for the given IP).
The port space is entirely independent of UDP, TCP or any other
protocol.
* Socket interface
RDS sockets work *mostly* as you would expect from a BSD
socket. The next section will cover the details. At any rate,
all I/O is performed through the standard BSD socket API.
Some additions like zerocopy support are implemented through
control messages, while other extensions use the getsockopt/
setsockopt calls.
Sockets must be bound before you can send or receive data.
This is needed because binding also selects a transport and
attaches it to the socket. Once bound, the transport assignment
does not change. RDS will tolerate IPs moving around (eg in
a active-active HA scenario), but only as long as the address
doesn't move to a different transport.
* sysctls
RDS supports a number of sysctls in /proc/sys/net/rds
Socket Interface
================
AF_RDS, PF_RDS, SOL_RDS
These constants haven't been assigned yet, because RDS isn't in
mainline yet. Currently, the kernel module assigns some constant
and publishes it to user space through two sysctl files
/proc/sys/net/rds/pf_rds
/proc/sys/net/rds/sol_rds
fd = socket(PF_RDS, SOCK_SEQPACKET, 0);
This creates a new, unbound RDS socket.
setsockopt(SOL_SOCKET): send and receive buffer size
RDS honors the send and receive buffer size socket options.
You are not allowed to queue more than SO_SNDSIZE bytes to
a socket. A message is queued when sendmsg is called, and
it leaves the queue when the remote system acknowledges
its arrival.
The SO_RCVSIZE option controls the maximum receive queue length.
This is a soft limit rather than a hard limit - RDS will
continue to accept and queue incoming messages, even if that
takes the queue length over the limit. However, it will also
mark the port as "congested" and send a congestion update to
the source node. The source node is supposed to throttle any
processes sending to this congested port.
bind(fd, &sockaddr_in, ...)
This binds the socket to a local IP address and port, and a
transport.
sendmsg(fd, ...)
Sends a message to the indicated recipient. The kernel will
transparently establish the underlying reliable connection
if it isn't up yet.
An attempt to send a message that exceeds SO_SNDSIZE will
return with -EMSGSIZE
An attempt to send a message that would take the total number
of queued bytes over the SO_SNDSIZE threshold will return
EAGAIN.
An attempt to send a message to a destination that is marked
as "congested" will return ENOBUFS.
recvmsg(fd, ...)
Receives a message that was queued to this socket. The sockets
recv queue accounting is adjusted, and if the queue length
drops below SO_SNDSIZE, the port is marked uncongested, and
a congestion update is sent to all peers.
Applications can ask the RDS kernel module to receive
notifications via control messages (for instance, there is a
notification when a congestion update arrived, or when a RDMA
operation completes). These notifications are received through
the msg.msg_control buffer of struct msghdr. The format of the
messages is described in manpages.
poll(fd)
RDS supports the poll interface to allow the application
to implement async I/O.
POLLIN handling is pretty straightforward. When there's an
incoming message queued to the socket, or a pending notification,
we signal POLLIN.
POLLOUT is a little harder. Since you can essentially send
to any destination, RDS will always signal POLLOUT as long as
there's room on the send queue (ie the number of bytes queued
is less than the sendbuf size).
However, the kernel will refuse to accept messages to
a destination marked congested - in this case you will loop
forever if you rely on poll to tell you what to do.
This isn't a trivial problem, but applications can deal with
this - by using congestion notifications, and by checking for
ENOBUFS errors returned by sendmsg.
setsockopt(SOL_RDS, RDS_CANCEL_SENT_TO, &sockaddr_in)
This allows the application to discard all messages queued to a
specific destination on this particular socket.
This allows the application to cancel outstanding messages if
it detects a timeout. For instance, if it tried to send a message,
and the remote host is unreachable, RDS will keep trying forever.
The application may decide it's not worth it, and cancel the
operation. In this case, it would use RDS_CANCEL_SENT_TO to
nuke any pending messages.
RDMA for RDS
============
see rds-rdma(7) manpage (available in rds-tools)
Congestion Notifications
========================
see rds(7) manpage
RDS Protocol
============
Message header
The message header is a 'struct rds_header' (see rds.h):
Fields:
h_sequence:
per-packet sequence number
h_ack:
piggybacked acknowledgment of last packet received
h_len:
length of data, not including header
h_sport:
source port
h_dport:
destination port
h_flags:
CONG_BITMAP - this is a congestion update bitmap
ACK_REQUIRED - receiver must ack this packet
RETRANSMITTED - packet has previously been sent
h_credit:
indicate to other end of connection that
it has more credits available (i.e. there is
more send room)
h_padding[4]:
unused, for future use
h_csum:
header checksum
h_exthdr:
optional data can be passed here. This is currently used for
passing RDMA-related information.
ACK and retransmit handling
One might think that with reliable IB connections you wouldn't need
to ack messages that have been received. The problem is that IB
hardware generates an ack message before it has DMAed the message
into memory. This creates a potential message loss if the HCA is
disabled for any reason between when it sends the ack and before
the message is DMAed and processed. This is only a potential issue
if another HCA is available for fail-over.
Sending an ack immediately would allow the sender to free the sent
message from their send queue quickly, but could cause excessive
traffic to be used for acks. RDS piggybacks acks on sent data
packets. Ack-only packets are reduced by only allowing one to be
in flight at a time, and by the sender only asking for acks when
its send buffers start to fill up. All retransmissions are also
acked.
Flow Control
RDS's IB transport uses a credit-based mechanism to verify that
there is space in the peer's receive buffers for more data. This
eliminates the need for hardware retries on the connection.
Congestion
Messages waiting in the receive queue on the receiving socket
are accounted against the sockets SO_RCVBUF option value. Only
the payload bytes in the message are accounted for. If the
number of bytes queued equals or exceeds rcvbuf then the socket
is congested. All sends attempted to this socket's address
should return block or return -EWOULDBLOCK.
Applications are expected to be reasonably tuned such that this
situation very rarely occurs. An application encountering this
"back-pressure" is considered a bug.
This is implemented by having each node maintain bitmaps which
indicate which ports on bound addresses are congested. As the
bitmap changes it is sent through all the connections which
terminate in the local address of the bitmap which changed.
The bitmaps are allocated as connections are brought up. This
avoids allocation in the interrupt handling path which queues
sages on sockets. The dense bitmaps let transports send the
entire bitmap on any bitmap change reasonably efficiently. This
is much easier to implement than some finer-grained
communication of per-port congestion. The sender does a very
inexpensive bit test to test if the port it's about to send to
is congested or not.
RDS Transport Layer
==================
As mentioned above, RDS is not IB-specific. Its code is divided
into a general RDS layer and a transport layer.
The general layer handles the socket API, congestion handling,
loopback, stats, usermem pinning, and the connection state machine.
The transport layer handles the details of the transport. The IB
transport, for example, handles all the queue pairs, work requests,
CM event handlers, and other Infiniband details.
RDS Kernel Structures
=====================
struct rds_message
aka possibly "rds_outgoing", the generic RDS layer copies data to
be sent and sets header fields as needed, based on the socket API.
This is then queued for the individual connection and sent by the
connection's transport.
struct rds_incoming
a generic struct referring to incoming data that can be handed from
the transport to the general code and queued by the general code
while the socket is awoken. It is then passed back to the transport
code to handle the actual copy-to-user.
struct rds_socket
per-socket information
struct rds_connection
per-connection information
struct rds_transport
pointers to transport-specific functions
struct rds_statistics
non-transport-specific statistics
struct rds_cong_map
wraps the raw congestion bitmap, contains rbnode, waitq, etc.
Connection management
=====================
Connections may be in UP, DOWN, CONNECTING, DISCONNECTING, and
ERROR states.
The first time an attempt is made by an RDS socket to send data to
a node, a connection is allocated and connected. That connection is
then maintained forever -- if there are transport errors, the
connection will be dropped and re-established.
Dropping a connection while packets are queued will cause queued or
partially-sent datagrams to be retransmitted when the connection is
re-established.
The send path
=============
rds_sendmsg()
struct rds_message built from incoming data
CMSGs parsed (e.g. RDMA ops)
transport connection alloced and connected if not already
rds_message placed on send queue
send worker awoken
rds_send_worker()
calls rds_send_xmit() until queue is empty
rds_send_xmit()
transmits congestion map if one is pending
may set ACK_REQUIRED
calls transport to send either non-RDMA or RDMA message
(RDMA ops never retransmitted)
rds_ib_xmit()
allocs work requests from send ring
adds any new send credits available to peer (h_credits)
maps the rds_message's sg list
piggybacks ack
populates work requests
post send to connection's queue pair
The recv path
=============
rds_ib_recv_cq_comp_handler()
looks at write completions
unmaps recv buffer from device
no errors, call rds_ib_process_recv()
refill recv ring
rds_ib_process_recv()
validate header checksum
copy header to rds_ib_incoming struct if start of a new datagram
add to ibinc's fraglist
if competed datagram:
update cong map if datagram was cong update
call rds_recv_incoming() otherwise
note if ack is required
rds_recv_incoming()
drop duplicate packets
respond to pings
find the sock associated with this datagram
add to sock queue
wake up sock
do some congestion calculations
rds_recvmsg
copy data into user iovec
handle CMSGs
return to application

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