summaryrefslogtreecommitdiff
path: root/Documentation
diff options
context:
space:
mode:
authorLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 16:38:06 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2014-04-07 16:38:06 -0700
commit26c12d93348f0bda0756aff83f4867d9ae58a5a6 (patch)
tree65221f6837c66a9260c5c973e5fb908b10e0d504 /Documentation
parentdc5ed40686a4da95881c35d913b60f867755cbe2 (diff)
parentfdc5813fbbd484a54c88477f91a78934cda8bb32 (diff)
Merge branch 'akpm' (incoming from Andrew)
Merge second patch-bomb from Andrew Morton: - the rest of MM - zram updates - zswap updates - exit - procfs - exec - wait - crash dump - lib/idr - rapidio - adfs, affs, bfs, ufs - cris - Kconfig things - initramfs - small amount of IPC material - percpu enhancements - early ioremap support - various other misc things * emailed patches from Andrew Morton <akpm@linux-foundation.org>: (156 commits) MAINTAINERS: update Intel C600 SAS driver maintainers fs/ufs: remove unused ufs_super_block_third pointer fs/ufs: remove unused ufs_super_block_second pointer fs/ufs: remove unused ufs_super_block_first pointer fs/ufs/super.c: add __init to init_inodecache() doc/kernel-parameters.txt: add early_ioremap_debug arm64: add early_ioremap support arm64: initialize pgprot info earlier in boot x86: use generic early_ioremap mm: create generic early_ioremap() support x86/mm: sparse warning fix for early_memremap lglock: map to spinlock when !CONFIG_SMP percpu: add preemption checks to __this_cpu ops vmstat: use raw_cpu_ops to avoid false positives on preemption checks slub: use raw_cpu_inc for incrementing statistics net: replace __this_cpu_inc in route.c with raw_cpu_inc modules: use raw_cpu_write for initialization of per cpu refcount. mm: use raw_cpu ops for determining current NUMA node percpu: add raw_cpu_ops slub: fix leak of 'name' in sysfs_slab_add ...
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/ABI/testing/sysfs-block-zram39
-rw-r--r--Documentation/DocBook/kernel-hacking.tmpl2
-rw-r--r--Documentation/arm64/memory.txt4
-rw-r--r--Documentation/blockdev/zram.txt54
-rw-r--r--Documentation/cgroups/memcg_test.txt4
-rw-r--r--Documentation/cgroups/resource_counter.txt12
-rw-r--r--Documentation/filesystems/Locking10
-rw-r--r--Documentation/filesystems/affs.txt9
-rw-r--r--Documentation/filesystems/proc.txt17
-rw-r--r--Documentation/irqflags-tracing.txt7
-rw-r--r--Documentation/kbuild/kconfig-language.txt4
-rw-r--r--Documentation/kernel-parameters.txt5
-rw-r--r--Documentation/rapidio/sysfs.txt66
-rw-r--r--Documentation/scheduler/sched-arch.txt2
-rw-r--r--Documentation/sysctl/kernel.txt1
15 files changed, 182 insertions, 54 deletions
diff --git a/Documentation/ABI/testing/sysfs-block-zram b/Documentation/ABI/testing/sysfs-block-zram
index 3f0b9ae61d8c..70ec992514d0 100644
--- a/Documentation/ABI/testing/sysfs-block-zram
+++ b/Documentation/ABI/testing/sysfs-block-zram
@@ -43,6 +43,36 @@ Description:
The invalid_io file is read-only and specifies the number of
non-page-size-aligned I/O requests issued to this device.
+What: /sys/block/zram<id>/failed_reads
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The failed_reads file is read-only and specifies the number of
+ failed reads happened on this device.
+
+What: /sys/block/zram<id>/failed_writes
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The failed_writes file is read-only and specifies the number of
+ failed writes happened on this device.
+
+What: /sys/block/zram<id>/max_comp_streams
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The max_comp_streams file is read-write and specifies the
+ number of backend's zcomp_strm compression streams (number of
+ concurrent compress operations).
+
+What: /sys/block/zram<id>/comp_algorithm
+Date: February 2014
+Contact: Sergey Senozhatsky <sergey.senozhatsky@gmail.com>
+Description:
+ The comp_algorithm file is read-write and lets to show
+ available and selected compression algorithms, change
+ compression algorithm selection.
+
What: /sys/block/zram<id>/notify_free
Date: August 2010
Contact: Nitin Gupta <ngupta@vflare.org>
@@ -53,15 +83,6 @@ Description:
is freed. This statistic is applicable only when this disk is
being used as a swap disk.
-What: /sys/block/zram<id>/discard
-Date: August 2010
-Contact: Nitin Gupta <ngupta@vflare.org>
-Description:
- The discard file is read-only and specifies the number of
- discard requests received by this device. These requests
- provide information to block device regarding blocks which are
- no longer used by filesystem.
-
What: /sys/block/zram<id>/zero_pages
Date: August 2010
Contact: Nitin Gupta <ngupta@vflare.org>
diff --git a/Documentation/DocBook/kernel-hacking.tmpl b/Documentation/DocBook/kernel-hacking.tmpl
index bd9015d10cff..e84f09467cd7 100644
--- a/Documentation/DocBook/kernel-hacking.tmpl
+++ b/Documentation/DocBook/kernel-hacking.tmpl
@@ -671,7 +671,7 @@ printk(KERN_INFO "my ip: %pI4\n", &amp;ipaddress);
<sect1 id="routines-local-irqs">
<title><function>local_irq_save()</function>/<function>local_irq_restore()</function>
- <filename class="headerfile">include/asm/system.h</filename>
+ <filename class="headerfile">include/linux/irqflags.h</filename>
</title>
<para>
diff --git a/Documentation/arm64/memory.txt b/Documentation/arm64/memory.txt
index 85e24c4f215c..d50fa618371b 100644
--- a/Documentation/arm64/memory.txt
+++ b/Documentation/arm64/memory.txt
@@ -39,7 +39,7 @@ ffffffbffa000000 ffffffbffaffffff 16MB PCI I/O space
ffffffbffb000000 ffffffbffbbfffff 12MB [guard]
-ffffffbffbc00000 ffffffbffbdfffff 2MB earlyprintk device
+ffffffbffbc00000 ffffffbffbdfffff 2MB fixed mappings
ffffffbffbe00000 ffffffbffbffffff 2MB [guard]
@@ -66,7 +66,7 @@ fffffdfffa000000 fffffdfffaffffff 16MB PCI I/O space
fffffdfffb000000 fffffdfffbbfffff 12MB [guard]
-fffffdfffbc00000 fffffdfffbdfffff 2MB earlyprintk device
+fffffdfffbc00000 fffffdfffbdfffff 2MB fixed mappings
fffffdfffbe00000 fffffdfffbffffff 2MB [guard]
diff --git a/Documentation/blockdev/zram.txt b/Documentation/blockdev/zram.txt
index 2eccddffa6c8..0595c3f56ccf 100644
--- a/Documentation/blockdev/zram.txt
+++ b/Documentation/blockdev/zram.txt
@@ -21,7 +21,43 @@ Following shows a typical sequence of steps for using zram.
This creates 4 devices: /dev/zram{0,1,2,3}
(num_devices parameter is optional. Default: 1)
-2) Set Disksize
+2) Set max number of compression streams
+ Compression backend may use up to max_comp_streams compression streams,
+ thus allowing up to max_comp_streams concurrent compression operations.
+ By default, compression backend uses single compression stream.
+
+ Examples:
+ #show max compression streams number
+ cat /sys/block/zram0/max_comp_streams
+
+ #set max compression streams number to 3
+ echo 3 > /sys/block/zram0/max_comp_streams
+
+Note:
+In order to enable compression backend's multi stream support max_comp_streams
+must be initially set to desired concurrency level before ZRAM device
+initialisation. Once the device initialised as a single stream compression
+backend (max_comp_streams equals to 1), you will see error if you try to change
+the value of max_comp_streams because single stream compression backend
+implemented as a special case by lock overhead issue and does not support
+dynamic max_comp_streams. Only multi stream backend supports dynamic
+max_comp_streams adjustment.
+
+3) Select compression algorithm
+ Using comp_algorithm device attribute one can see available and
+ currently selected (shown in square brackets) compression algortithms,
+ change selected compression algorithm (once the device is initialised
+ there is no way to change compression algorithm).
+
+ Examples:
+ #show supported compression algorithms
+ cat /sys/block/zram0/comp_algorithm
+ lzo [lz4]
+
+ #select lzo compression algorithm
+ echo lzo > /sys/block/zram0/comp_algorithm
+
+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:
@@ -33,32 +69,38 @@ Following shows a typical sequence of steps for using zram.
echo 512M > /sys/block/zram0/disksize
echo 1G > /sys/block/zram0/disksize
-3) Activate:
+Note:
+There is little point creating a zram of greater than twice the size of memory
+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) Activate:
mkswap /dev/zram0
swapon /dev/zram0
mkfs.ext4 /dev/zram1
mount /dev/zram1 /tmp
-4) Stats:
+6) Stats:
Per-device statistics are exported as various nodes under
/sys/block/zram<id>/
disksize
num_reads
num_writes
+ failed_reads
+ failed_writes
invalid_io
notify_free
- discard
zero_pages
orig_data_size
compr_data_size
mem_used_total
-5) Deactivate:
+7) Deactivate:
swapoff /dev/zram0
umount /dev/zram1
-6) Reset:
+8) Reset:
Write any positive value to 'reset' sysfs node
echo 1 > /sys/block/zram0/reset
echo 1 > /sys/block/zram1/reset
diff --git a/Documentation/cgroups/memcg_test.txt b/Documentation/cgroups/memcg_test.txt
index ce94a83a7d9a..80ac454704b8 100644
--- a/Documentation/cgroups/memcg_test.txt
+++ b/Documentation/cgroups/memcg_test.txt
@@ -24,7 +24,7 @@ Please note that implementation details can be changed.
a page/swp_entry may be charged (usage += PAGE_SIZE) at
- mem_cgroup_newpage_charge()
+ mem_cgroup_charge_anon()
Called at new page fault and Copy-On-Write.
mem_cgroup_try_charge_swapin()
@@ -32,7 +32,7 @@ Please note that implementation details can be changed.
Followed by charge-commit-cancel protocol. (With swap accounting)
At commit, a charge recorded in swap_cgroup is removed.
- mem_cgroup_cache_charge()
+ mem_cgroup_charge_file()
Called at add_to_page_cache()
mem_cgroup_cache_charge_swapin()
diff --git a/Documentation/cgroups/resource_counter.txt b/Documentation/cgroups/resource_counter.txt
index 5108afb3645c..762ca54eb929 100644
--- a/Documentation/cgroups/resource_counter.txt
+++ b/Documentation/cgroups/resource_counter.txt
@@ -76,15 +76,7 @@ to work with it.
limit_fail_at parameter is set to the particular res_counter element
where the charging failed.
- d. int res_counter_charge_locked
- (struct res_counter *rc, unsigned long val, bool force)
-
- The same as res_counter_charge(), but it must not acquire/release the
- res_counter->lock internally (it must be called with res_counter->lock
- held). The force parameter indicates whether we can bypass the limit.
-
- e. u64 res_counter_uncharge[_locked]
- (struct res_counter *rc, unsigned long val)
+ d. u64 res_counter_uncharge(struct res_counter *rc, unsigned long val)
When a resource is released (freed) it should be de-accounted
from the resource counter it was accounted to. This is called
@@ -93,7 +85,7 @@ to work with it.
The _locked routines imply that the res_counter->lock is taken.
- f. u64 res_counter_uncharge_until
+ e. u64 res_counter_uncharge_until
(struct res_counter *rc, struct res_counter *top,
unsigned long val)
diff --git a/Documentation/filesystems/Locking b/Documentation/filesystems/Locking
index f424e0e5b46b..efca5c1bbb10 100644
--- a/Documentation/filesystems/Locking
+++ b/Documentation/filesystems/Locking
@@ -529,6 +529,7 @@ locking rules:
open: yes
close: yes
fault: yes can return with page locked
+map_pages: yes
page_mkwrite: yes can return with page locked
access: yes
@@ -540,6 +541,15 @@ the page, then ensure it is not already truncated (the page lock will block
subsequent truncate), and then return with VM_FAULT_LOCKED, and the page
locked. The VM will unlock the page.
+ ->map_pages() is called when VM asks to map easy accessible pages.
+Filesystem should find and map pages associated with offsets from "pgoff"
+till "max_pgoff". ->map_pages() is called with page table locked and must
+not block. If it's not possible to reach a page without blocking,
+filesystem should skip it. Filesystem should use do_set_pte() to setup
+page table entry. Pointer to entry associated with offset "pgoff" is
+passed in "pte" field in vm_fault structure. Pointers to entries for other
+offsets should be calculated relative to "pte".
+
->page_mkwrite() is called when a previously read-only pte is
about to become writeable. The filesystem again must ensure that there are
no truncate/invalidate races, and then return with the page locked. If
diff --git a/Documentation/filesystems/affs.txt b/Documentation/filesystems/affs.txt
index 81ac488e3758..71b63c2b9841 100644
--- a/Documentation/filesystems/affs.txt
+++ b/Documentation/filesystems/affs.txt
@@ -49,6 +49,10 @@ mode=mode Sets the mode flags to the given (octal) value, regardless
This is useful since most of the plain AmigaOS files
will map to 600.
+nofilenametruncate
+ The file system will return an error when filename exceeds
+ standard maximum filename length (30 characters).
+
reserved=num Sets the number of reserved blocks at the start of the
partition to num. You should never need this option.
Default is 2.
@@ -181,9 +185,8 @@ tested, though several hundred MB have been read and written using
this fs. For a most up-to-date list of bugs please consult
fs/affs/Changes.
-Filenames are truncated to 30 characters without warning (this
-can be changed by setting the compile-time option AFFS_NO_TRUNCATE
-in include/linux/amigaffs.h).
+By default, filenames are truncated to 30 characters without warning.
+'nofilenametruncate' mount option can change that behavior.
Case is ignored by the affs in filename matching, but Linux shells
do care about the case. Example (with /wb being an affs mounted fs):
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index f00bee144add..8b9cd8eb3f91 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -1648,18 +1648,21 @@ pids, so one need to either stop or freeze processes being inspected
if precise results are needed.
-3.7 /proc/<pid>/fdinfo/<fd> - Information about opened file
+3.8 /proc/<pid>/fdinfo/<fd> - Information about opened file
---------------------------------------------------------------
This file provides information associated with an opened file. The regular
-files have at least two fields -- 'pos' and 'flags'. The 'pos' represents
-the current offset of the opened file in decimal form [see lseek(2) for
-details] and 'flags' denotes the octal O_xxx mask the file has been
-created with [see open(2) for details].
+files have at least three fields -- 'pos', 'flags' and mnt_id. The 'pos'
+represents the current offset of the opened file in decimal form [see lseek(2)
+for details], 'flags' denotes the octal O_xxx mask the file has been
+created with [see open(2) for details] and 'mnt_id' represents mount ID of
+the file system containing the opened file [see 3.5 /proc/<pid>/mountinfo
+for details].
A typical output is
pos: 0
flags: 0100002
+ mnt_id: 19
The files such as eventfd, fsnotify, signalfd, epoll among the regular pos/flags
pair provide additional information particular to the objects they represent.
@@ -1668,6 +1671,7 @@ pair provide additional information particular to the objects they represent.
~~~~~~~~~~~~~
pos: 0
flags: 04002
+ mnt_id: 9
eventfd-count: 5a
where 'eventfd-count' is hex value of a counter.
@@ -1676,6 +1680,7 @@ pair provide additional information particular to the objects they represent.
~~~~~~~~~~~~~~
pos: 0
flags: 04002
+ mnt_id: 9
sigmask: 0000000000000200
where 'sigmask' is hex value of the signal mask associated
@@ -1685,6 +1690,7 @@ pair provide additional information particular to the objects they represent.
~~~~~~~~~~~
pos: 0
flags: 02
+ mnt_id: 9
tfd: 5 events: 1d data: ffffffffffffffff
where 'tfd' is a target file descriptor number in decimal form,
@@ -1718,6 +1724,7 @@ pair provide additional information particular to the objects they represent.
pos: 0
flags: 02
+ mnt_id: 9
fanotify flags:10 event-flags:0
fanotify mnt_id:12 mflags:40 mask:38 ignored_mask:40000003
fanotify ino:4f969 sdev:800013 mflags:0 mask:3b ignored_mask:40000000 fhandle-bytes:8 fhandle-type:1 f_handle:69f90400c275b5b4
diff --git a/Documentation/irqflags-tracing.txt b/Documentation/irqflags-tracing.txt
index 67aa71e73035..f6da05670e16 100644
--- a/Documentation/irqflags-tracing.txt
+++ b/Documentation/irqflags-tracing.txt
@@ -22,13 +22,6 @@ rather straightforward and risk-free manner.
Architectures that want to support this need to do a couple of
code-organizational changes first:
-- move their irq-flags manipulation code from their asm/system.h header
- to asm/irqflags.h
-
-- rename local_irq_disable()/etc to raw_local_irq_disable()/etc. so that
- the linux/irqflags.h code can inject callbacks and can construct the
- real local_irq_disable()/etc APIs.
-
- add and enable TRACE_IRQFLAGS_SUPPORT in their arch level Kconfig file
and then a couple of functional changes are needed as well to implement
diff --git a/Documentation/kbuild/kconfig-language.txt b/Documentation/kbuild/kconfig-language.txt
index c420676c6fe3..350f733bf2c7 100644
--- a/Documentation/kbuild/kconfig-language.txt
+++ b/Documentation/kbuild/kconfig-language.txt
@@ -157,6 +157,10 @@ applicable everywhere (see syntax).
to the build environment (if this is desired, it can be done via
another symbol).
+ - "allnoconfig_y"
+ This declares the symbol as one that should have the value y when
+ using "allnoconfig". Used for symbols that hide other symbols.
+
Menu dependencies
-----------------
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index bc3478581f67..b6c67d592be5 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -884,6 +884,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
Enable debug messages at boot time. See
Documentation/dynamic-debug-howto.txt for details.
+ early_ioremap_debug [KNL]
+ Enable debug messages in early_ioremap support. This
+ is useful for tracking down temporary early mappings
+ which are not unmapped.
+
earlycon= [KNL] Output early console device and options.
uart[8250],io,<addr>[,options]
uart[8250],mmio,<addr>[,options]
diff --git a/Documentation/rapidio/sysfs.txt b/Documentation/rapidio/sysfs.txt
index 271438c0617f..47ce9a5336e1 100644
--- a/Documentation/rapidio/sysfs.txt
+++ b/Documentation/rapidio/sysfs.txt
@@ -2,8 +2,8 @@
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
-1. Device Subdirectories
-------------------------
+1. RapidIO Device Subdirectories
+--------------------------------
For each RapidIO device, the RapidIO subsystem creates files in an individual
subdirectory with the following name, /sys/bus/rapidio/devices/<device_name>.
@@ -25,8 +25,8 @@ seen by the enumerating host (destID = 1):
NOTE: An enumerating or discovering endpoint does not create a sysfs entry for
itself, this is why an endpoint with destID=1 is not shown in the list.
-2. Attributes Common for All Devices
-------------------------------------
+2. Attributes Common for All RapidIO Devices
+--------------------------------------------
Each device subdirectory contains the following informational read-only files:
@@ -52,16 +52,16 @@ This attribute is similar in behavior to the "config" attribute of PCI devices
and provides an access to the RapidIO device registers using standard file read
and write operations.
-3. Endpoint Device Attributes
------------------------------
+3. RapidIO Endpoint Device Attributes
+-------------------------------------
Currently Linux RapidIO subsystem does not create any endpoint specific sysfs
attributes. It is possible that RapidIO master port drivers and endpoint device
drivers will add their device-specific sysfs attributes but such attributes are
outside the scope of this document.
-4. Switch Device Attributes
----------------------------
+4. RapidIO Switch Device Attributes
+-----------------------------------
RapidIO switches have additional attributes in sysfs. RapidIO subsystem supports
common and device-specific sysfs attributes for switches. Because switches are
@@ -106,3 +106,53 @@ attribute:
for that controller always will be 0.
To initiate RapidIO enumeration/discovery on all available mports
a user must write '-1' (or RIO_MPORT_ANY) into this attribute file.
+
+
+6. RapidIO Bus Controllers/Ports
+--------------------------------
+
+On-chip RapidIO controllers and PCIe-to-RapidIO bridges (referenced as
+"Master Port" or "mport") are presented in sysfs as the special class of
+devices: "rapidio_port".
+
+The /sys/class/rapidio_port subdirectory contains individual subdirectories
+named as "rapidioN" where N = mport ID registered with RapidIO subsystem.
+
+NOTE: An mport ID is not a RapidIO destination ID assigned to a given local
+mport device.
+
+Each mport device subdirectory in addition to standard entries contains the
+following device-specific attributes:
+
+ port_destid - reports RapidIO destination ID assigned to the given RapidIO
+ mport device. If value 0xFFFFFFFF is returned this means that
+ no valid destination ID have been assigned to the mport (yet).
+ Normally, before enumeration/discovery have been executed only
+ fabric enumerating mports have a valid destination ID assigned
+ to them using "hdid=..." rapidio module parameter.
+ sys_size - reports RapidIO common transport system size:
+ 0 = small (8-bit destination ID, max. 256 devices),
+ 1 = large (16-bit destination ID, max. 65536 devices).
+
+After enumeration or discovery was performed for a given mport device,
+the corresponding subdirectory will also contain subdirectories for each
+child RapidIO device connected to the mport. Naming conventions for RapidIO
+devices are described in Section 1 above.
+
+The example below shows mport device subdirectory with several child RapidIO
+devices attached to it.
+
+[rio@rapidio ~]$ ls /sys/class/rapidio_port/rapidio0/ -l
+total 0
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0001
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0004
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:e:0007
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0002
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0003
+drwxr-xr-x 3 root root 0 Feb 11 15:10 00:s:0005
+lrwxrwxrwx 1 root root 0 Feb 11 15:11 device -> ../../../0000:01:00.0
+-r--r--r-- 1 root root 4096 Feb 11 15:11 port_destid
+drwxr-xr-x 2 root root 0 Feb 11 15:11 power
+lrwxrwxrwx 1 root root 0 Feb 11 15:04 subsystem -> ../../../../../../class/rapidio_port
+-r--r--r-- 1 root root 4096 Feb 11 15:11 sys_size
+-rw-r--r-- 1 root root 4096 Feb 11 15:04 uevent
diff --git a/Documentation/scheduler/sched-arch.txt b/Documentation/scheduler/sched-arch.txt
index 9290de703450..a2f27bbf2cba 100644
--- a/Documentation/scheduler/sched-arch.txt
+++ b/Documentation/scheduler/sched-arch.txt
@@ -8,7 +8,7 @@ Context switch
By default, the switch_to arch function is called with the runqueue
locked. This is usually not a problem unless switch_to may need to
take the runqueue lock. This is usually due to a wake up operation in
-the context switch. See arch/ia64/include/asm/system.h for an example.
+the context switch. See arch/ia64/include/asm/switch_to.h for an example.
To request the scheduler call switch_to with the runqueue unlocked,
you must `#define __ARCH_WANT_UNLOCKED_CTXSW` in a header file
diff --git a/Documentation/sysctl/kernel.txt b/Documentation/sysctl/kernel.txt
index 271a09db6629..9886c3d57fc2 100644
--- a/Documentation/sysctl/kernel.txt
+++ b/Documentation/sysctl/kernel.txt
@@ -317,6 +317,7 @@ for more than this value report a warning.
This file shows up if CONFIG_DETECT_HUNG_TASK is enabled.
0: means infinite timeout - no checking done.
+Possible values to set are in range {0..LONG_MAX/HZ}.
==============================================================