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r: 212090
b: refs/heads/master
c: 9863c90
h: refs/heads/master
v: v3
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Alok Kataria authored and H. Peter Anvin committed Aug 23, 2010
1 parent aca2ab1 commit 0a52dba
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2 changes: 1 addition & 1 deletion [refs]
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@@ -1,2 +1,2 @@
---
refs/heads/master: cca8209ed962f87990345ba073979d2b55dd1187
refs/heads/master: 9863c90f682fba34cdc26c3437e8c00da6c83fa4
8 changes: 4 additions & 4 deletions trunk/CREDITS
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Expand Up @@ -3554,12 +3554,12 @@ E: cvance@nai.com
D: portions of the Linux Security Module (LSM) framework and security modules

N: Petr Vandrovec
E: petr@vandrovec.name
E: vandrove@vc.cvut.cz
D: Small contributions to ncpfs
D: Matrox framebuffer driver
S: 21513 Conradia Ct
S: Cupertino, CA 95014
S: USA
S: Chudenicka 8
S: 10200 Prague 10, Hostivar
S: Czech Republic

N: Thibaut Varene
E: T-Bone@parisc-linux.org
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1 change: 1 addition & 0 deletions trunk/Documentation/DocBook/device-drivers.tmpl
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Expand Up @@ -46,6 +46,7 @@

<sect1><title>Atomic and pointer manipulation</title>
!Iarch/x86/include/asm/atomic.h
!Iarch/x86/include/asm/unaligned.h
</sect1>

<sect1><title>Delaying, scheduling, and timer routines</title>
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1 change: 1 addition & 0 deletions trunk/Documentation/DocBook/kernel-api.tmpl
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Expand Up @@ -57,6 +57,7 @@
</para>

<sect1><title>String Conversions</title>
!Ilib/vsprintf.c
!Elib/vsprintf.c
</sect1>
<sect1><title>String Manipulation</title>
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20 changes: 10 additions & 10 deletions trunk/Documentation/DocBook/kernel-locking.tmpl
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Expand Up @@ -1645,9 +1645,7 @@ the amount of locking which needs to be done.
all the readers who were traversing the list when we deleted the
element are finished. We use <function>call_rcu()</function> to
register a callback which will actually destroy the object once
all pre-existing readers are finished. Alternatively,
<function>synchronize_rcu()</function> may be used to block until
all pre-existing are finished.
the readers are finished.
</para>
<para>
But how does Read Copy Update know when the readers are
Expand Down Expand Up @@ -1716,7 +1714,7 @@ the amount of locking which needs to be done.
- object_put(obj);
+ list_del_rcu(&amp;obj-&gt;list);
cache_num--;
+ call_rcu(&amp;obj-&gt;rcu, cache_delete_rcu);
+ call_rcu(&amp;obj-&gt;rcu, cache_delete_rcu, obj);
}

/* Must be holding cache_lock */
Expand All @@ -1727,6 +1725,14 @@ the amount of locking which needs to be done.
if (++cache_num > MAX_CACHE_SIZE) {
struct object *i, *outcast = NULL;
list_for_each_entry(i, &amp;cache, list) {
@@ -85,6 +94,7 @@
obj-&gt;popularity = 0;
atomic_set(&amp;obj-&gt;refcnt, 1); /* The cache holds a reference */
spin_lock_init(&amp;obj-&gt;lock);
+ INIT_RCU_HEAD(&amp;obj-&gt;rcu);

spin_lock_irqsave(&amp;cache_lock, flags);
__cache_add(obj);
@@ -104,12 +114,11 @@
struct object *cache_find(int id)
{
Expand Down Expand Up @@ -1955,12 +1961,6 @@ machines due to caching.
</sect1>
</chapter>

<chapter id="apiref">
<title>Mutex API reference</title>
!Iinclude/linux/mutex.h
!Ekernel/mutex.c
</chapter>

<chapter id="references">
<title>Further reading</title>

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5 changes: 0 additions & 5 deletions trunk/Documentation/DocBook/tracepoint.tmpl
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Expand Up @@ -104,9 +104,4 @@
<title>Block IO</title>
!Iinclude/trace/events/block.h
</chapter>

<chapter id="workqueue">
<title>Workqueue</title>
!Iinclude/trace/events/workqueue.h
</chapter>
</book>
46 changes: 7 additions & 39 deletions trunk/Documentation/RCU/checklist.txt
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Expand Up @@ -218,22 +218,13 @@ over a rather long period of time, but improvements are always welcome!
include:

a. Keeping a count of the number of data-structure elements
used by the RCU-protected data structure, including
those waiting for a grace period to elapse. Enforce a
limit on this number, stalling updates as needed to allow
previously deferred frees to complete. Alternatively,
limit only the number awaiting deferred free rather than
the total number of elements.

One way to stall the updates is to acquire the update-side
mutex. (Don't try this with a spinlock -- other CPUs
spinning on the lock could prevent the grace period
from ever ending.) Another way to stall the updates
is for the updates to use a wrapper function around
the memory allocator, so that this wrapper function
simulates OOM when there is too much memory awaiting an
RCU grace period. There are of course many other
variations on this theme.
used by the RCU-protected data structure, including those
waiting for a grace period to elapse. Enforce a limit
on this number, stalling updates as needed to allow
previously deferred frees to complete.

Alternatively, limit only the number awaiting deferred
free rather than the total number of elements.

b. Limiting update rate. For example, if updates occur only
once per hour, then no explicit rate limiting is required,
Expand Down Expand Up @@ -374,26 +365,3 @@ over a rather long period of time, but improvements are always welcome!
and the compiler to freely reorder code into and out of RCU
read-side critical sections. It is the responsibility of the
RCU update-side primitives to deal with this.

17. Use CONFIG_PROVE_RCU, CONFIG_DEBUG_OBJECTS_RCU_HEAD, and
the __rcu sparse checks to validate your RCU code. These
can help find problems as follows:

CONFIG_PROVE_RCU: check that accesses to RCU-protected data
structures are carried out under the proper RCU
read-side critical section, while holding the right
combination of locks, or whatever other conditions
are appropriate.

CONFIG_DEBUG_OBJECTS_RCU_HEAD: check that you don't pass the
same object to call_rcu() (or friends) before an RCU
grace period has elapsed since the last time that you
passed that same object to call_rcu() (or friends).

__rcu sparse checks: tag the pointer to the RCU-protected data
structure with __rcu, and sparse will warn you if you
access that pointer without the services of one of the
variants of rcu_dereference().

These debugging aids can help you find problems that are
otherwise extremely difficult to spot.
18 changes: 0 additions & 18 deletions trunk/Documentation/RCU/stallwarn.txt
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Expand Up @@ -80,24 +80,6 @@ o A CPU looping with bottom halves disabled. This condition can
o For !CONFIG_PREEMPT kernels, a CPU looping anywhere in the kernel
without invoking schedule().

o A CPU-bound real-time task in a CONFIG_PREEMPT kernel, which might
happen to preempt a low-priority task in the middle of an RCU
read-side critical section. This is especially damaging if
that low-priority task is not permitted to run on any other CPU,
in which case the next RCU grace period can never complete, which
will eventually cause the system to run out of memory and hang.
While the system is in the process of running itself out of
memory, you might see stall-warning messages.

o A CPU-bound real-time task in a CONFIG_PREEMPT_RT kernel that
is running at a higher priority than the RCU softirq threads.
This will prevent RCU callbacks from ever being invoked,
and in a CONFIG_TREE_PREEMPT_RCU kernel will further prevent
RCU grace periods from ever completing. Either way, the
system will eventually run out of memory and hang. In the
CONFIG_TREE_PREEMPT_RCU case, you might see stall-warning
messages.

o A bug in the RCU implementation.

o A hardware failure. This is quite unlikely, but has occurred
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13 changes: 1 addition & 12 deletions trunk/Documentation/RCU/trace.txt
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Expand Up @@ -125,17 +125,6 @@ o "b" is the batch limit for this CPU. If more than this number
of RCU callbacks is ready to invoke, then the remainder will
be deferred.

o "ci" is the number of RCU callbacks that have been invoked for
this CPU. Note that ci+ql is the number of callbacks that have
been registered in absence of CPU-hotplug activity.

o "co" is the number of RCU callbacks that have been orphaned due to
this CPU going offline.

o "ca" is the number of RCU callbacks that have been adopted due to
other CPUs going offline. Note that ci+co-ca+ql is the number of
RCU callbacks registered on this CPU.

There is also an rcu/rcudata.csv file with the same information in
comma-separated-variable spreadsheet format.

Expand Down Expand Up @@ -191,7 +180,7 @@ o "s" is the "signaled" state that drives force_quiescent_state()'s

o "jfq" is the number of jiffies remaining for this grace period
before force_quiescent_state() is invoked to help push things
along. Note that CPUs in dyntick-idle mode throughout the grace
along. Note that CPUs in dyntick-idle mode thoughout the grace
period will not report on their own, but rather must be check by
some other CPU via force_quiescent_state().

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45 changes: 0 additions & 45 deletions trunk/Documentation/block/cfq-iosched.txt

This file was deleted.

28 changes: 0 additions & 28 deletions trunk/Documentation/cgroups/blkio-controller.txt
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Expand Up @@ -217,7 +217,6 @@ Details of cgroup files
CFQ sysfs tunable
=================
/sys/block/<disk>/queue/iosched/group_isolation
-----------------------------------------------

If group_isolation=1, it provides stronger isolation between groups at the
expense of throughput. By default group_isolation is 0. In general that
Expand All @@ -244,33 +243,6 @@ By default one should run with group_isolation=0. If that is not sufficient
and one wants stronger isolation between groups, then set group_isolation=1
but this will come at cost of reduced throughput.

/sys/block/<disk>/queue/iosched/slice_idle
------------------------------------------
On a faster hardware CFQ can be slow, especially with sequential workload.
This happens because CFQ idles on a single queue and single queue might not
drive deeper request queue depths to keep the storage busy. In such scenarios
one can try setting slice_idle=0 and that would switch CFQ to IOPS
(IO operations per second) mode on NCQ supporting hardware.

That means CFQ will not idle between cfq queues of a cfq group and hence be
able to driver higher queue depth and achieve better throughput. That also
means that cfq provides fairness among groups in terms of IOPS and not in
terms of disk time.

/sys/block/<disk>/queue/iosched/group_idle
------------------------------------------
If one disables idling on individual cfq queues and cfq service trees by
setting slice_idle=0, group_idle kicks in. That means CFQ will still idle
on the group in an attempt to provide fairness among groups.

By default group_idle is same as slice_idle and does not do anything if
slice_idle is enabled.

One can experience an overall throughput drop if you have created multiple
groups and put applications in that group which are not driving enough
IO to keep disk busy. In that case set group_idle=0, and CFQ will not idle
on individual groups and throughput should improve.

What works
==========
- Currently only sync IO queues are support. All the buffered writes are
Expand Down
23 changes: 3 additions & 20 deletions trunk/Documentation/cputopology.txt
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Expand Up @@ -14,39 +14,25 @@ to /proc/cpuinfo.
identifier (rather than the kernel's). The actual value is
architecture and platform dependent.

3) /sys/devices/system/cpu/cpuX/topology/book_id:

the book ID of cpuX. Typically it is the hardware platform's
identifier (rather than the kernel's). The actual value is
architecture and platform dependent.

4) /sys/devices/system/cpu/cpuX/topology/thread_siblings:
3) /sys/devices/system/cpu/cpuX/topology/thread_siblings:

internel kernel map of cpuX's hardware threads within the same
core as cpuX

5) /sys/devices/system/cpu/cpuX/topology/core_siblings:
4) /sys/devices/system/cpu/cpuX/topology/core_siblings:

internal kernel map of cpuX's hardware threads within the same
physical_package_id.

6) /sys/devices/system/cpu/cpuX/topology/book_siblings:

internal kernel map of cpuX's hardware threads within the same
book_id.

To implement it in an architecture-neutral way, a new source file,
drivers/base/topology.c, is to export the 4 or 6 attributes. The two book
related sysfs files will only be created if CONFIG_SCHED_BOOK is selected.
drivers/base/topology.c, is to export the 4 attributes.

For an architecture to support this feature, it must define some of
these macros in include/asm-XXX/topology.h:
#define topology_physical_package_id(cpu)
#define topology_core_id(cpu)
#define topology_book_id(cpu)
#define topology_thread_cpumask(cpu)
#define topology_core_cpumask(cpu)
#define topology_book_cpumask(cpu)

The type of **_id is int.
The type of siblings is (const) struct cpumask *.
Expand All @@ -59,9 +45,6 @@ not defined by include/asm-XXX/topology.h:
3) thread_siblings: just the given CPU
4) core_siblings: just the given CPU

For architectures that don't support books (CONFIG_SCHED_BOOK) there are no
default definitions for topology_book_id() and topology_book_cpumask().

Additionally, CPU topology information is provided under
/sys/devices/system/cpu and includes these files. The internal
source for the output is in brackets ("[]").
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28 changes: 0 additions & 28 deletions trunk/Documentation/feature-removal-schedule.txt
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Expand Up @@ -386,34 +386,6 @@ Who: Tejun Heo <tj@kernel.org>

----------------------------

What: Support for VMware's guest paravirtuliazation technique [VMI] will be
dropped.
When: 2.6.37 or earlier.
Why: With the recent innovations in CPU hardware acceleration technologies
from Intel and AMD, VMware ran a few experiments to compare these
techniques to guest paravirtualization technique on VMware's platform.
These hardware assisted virtualization techniques have outperformed the
performance benefits provided by VMI in most of the workloads. VMware
expects that these hardware features will be ubiquitous in a couple of
years, as a result, VMware has started a phased retirement of this
feature from the hypervisor. We will be removing this feature from the
Kernel too. Right now we are targeting 2.6.37 but can retire earlier if
technical reasons (read opportunity to remove major chunk of pvops)
arise.

Please note that VMI has always been an optimization and non-VMI kernels
still work fine on VMware's platform.
Latest versions of VMware's product which support VMI are,
Workstation 7.0 and VSphere 4.0 on ESX side, future maintainence
releases for these products will continue supporting VMI.

For more details about VMI retirement take a look at this,
http://blogs.vmware.com/guestosguide/2009/09/vmi-retirement.html

Who: Alok N Kataria <akataria@vmware.com>

----------------------------

What: Support for lcd_switch and display_get in asus-laptop driver
When: March 2010
Why: These two features use non-standard interfaces. There are the
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