Commit Graph

15114 Commits

Author SHA1 Message Date
Frederic Weisbecker
12351ef8f9 perf: Kick full dynticks CPU if events rotation is needed
Kick the current CPU's tick by sending it a self IPI when
an event is queued on the rotation list and it is the first
element inserted. This makes sure that perf_event_task_tick()
works on full dynticks CPUs.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Stephane Eranian <eranian@google.com>
Cc: Jiri Olsa <jolsa@redhat.com>
2013-04-22 19:59:37 +02:00
Frederic Weisbecker
6ac29178b4 posix_timers: Fix pre-condition to stop the tick on full dynticks
The test that checks if a CPU can stop its tick from posix CPU
timers angle was mistakenly inverted.

What we want is to prevent the tick from being stopped as long
as the current CPU's task runs a posix CPU timer.

Fix this.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-22 19:59:25 +02:00
Ingo Molnar
a166fcf04d Merge branch 'timers/nohz-posix-timers-v2' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into timers/nohz
Pull posix cpu timers handling on full dynticks from Frederic Weisbecker.

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-04-21 11:05:47 +02:00
Frederic Weisbecker
555347f6c0 posix_timers: New API to prevent from stopping the tick when timers are running
Bring a new helper that the full dynticks infrastructure can
call in order to know if it can safely stop the tick from
the posix cpu timers subsystem point of view.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-19 16:31:40 +02:00
Frederic Weisbecker
a85721601a posix_timers: Kick full dynticks CPUs when a posix cpu timer is armed
Kick the full dynticks CPUs when a posix cpu timer is enqueued by
way of a standard call to posix_cpu_timer_set() or set_process_cpu_timer().
This also include rescheduled firing timers.

This way they can re-evaluate the state of (and possibly restart) their
tick against the new expiry modification.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-19 16:30:13 +02:00
Frederic Weisbecker
f98823ac75 nohz: New option to default all CPUs in full dynticks range
Provide a new kernel config that defaults all CPUs to be part
of the full dynticks range, except the boot one for timekeeping.

This default setting is overriden by the nohz_full= boot option
if passed by the user.

This is helpful for those who don't need a finegrained range
of full dynticks CPU and also for automated testing.

Suggested-by: Ingo Molnar <mingo@kernel.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-19 13:54:16 +02:00
Frederic Weisbecker
d1e43fa5f8 nohz: Ensure full dynticks CPUs are RCU nocbs
We need full dynticks CPU to also be RCU nocb so
that we don't have to keep the tick to handle RCU
callbacks.

Make sure the range passed to nohz_full= boot
parameter is a subset of rcu_nocbs=

The CPUs that fail to meet this requirement will be
excluded from the nohz_full range. This is checked
early in boot time, before any CPU has the opportunity
to stop its tick.

Suggested-by: Steven Rostedt <rostedt@goodmis.org>
Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-19 13:54:04 +02:00
Frederic Weisbecker
0453b435df nohz: Force boot CPU outside full dynticks range
The timekeeping job must be able to run early on boot
because there may be some pre-SMP (and thus pre-initcalls )
components that rely on it. The IO-APIC is one such users
as it tests the timer health by watching jiffies progression.

Given that it happens before we know the initial online
set, we can't rely on it to select a timekeeper. We need
one before SMP time otherwise we simply crash on boot.

To fix this and keep things simple for now, force the boot CPU
outside of the full dynticks range in any case and do this early
on kernel parameter parsing time.

We might want a trickier solution later, expecially for aSMP
architectures that need to assign housekeeping tasks to arbitrary
low power CPUs.

But it's still first pass KISS time for now.

Reviewed-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-19 13:53:14 +02:00
Frederic Weisbecker
76c24fb054 nohz: New APIs to re-evaluate the tick on full dynticks CPUs
Provide two new helpers in order to notify the full dynticks CPUs about
some internal system changes against which they may reconsider the state
of their tick. Some practical examples include: posix cpu timers, perf tick
and sched clock tick.

For now the notifying handler, implemented through IPIs, is a stub
that will be implemented when we get the tick stop/restart infrastructure
in.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Oleg Nesterov <oleg@redhat.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-18 18:53:34 +02:00
Paul E. McKenney
65d798f0f9 rcu: Kick adaptive-ticks CPUs that are holding up RCU grace periods
Adaptive-ticks CPUs inform RCU when they enter kernel mode, but they do
not necessarily turn the scheduler-clock tick back on.  This state of
affairs could result in RCU waiting on an adaptive-ticks CPU running
for an extended period in kernel mode.  Such a CPU will never run the
RCU state machine, and could therefore indefinitely extend the RCU state
machine, sooner or later resulting in an OOM condition.

This patch, inspired by an earlier patch by Frederic Weisbecker, therefore
causes RCU's force-quiescent-state processing to check for this condition
and to send an IPI to CPUs that remain in that state for too long.
"Too long" currently means about three jiffies by default, which is
quite some time for a CPU to remain in the kernel without blocking.
The rcu_tree.jiffies_till_first_fqs and rcutree.jiffies_till_next_fqs
sysfs variables may be used to tune "too long" if needed.

Reported-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Reviewed-by: Josh Triplett <josh@joshtriplett.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-15 20:18:36 +02:00
Frederic Weisbecker
fae30dd669 nohz: Improve a bit the full dynticks Kconfig documentation
Remove the "single task" statement from CONFIG_NO_HZ_FULL
title. The constraint can be invalidated when tasks from
other sched classes than SCHED_FAIR are running. Moreover
it's possible that hrtick join the party in the future.

Also add a line about the dependency on SMP.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-15 20:18:04 +02:00
Frederic Weisbecker
5b533f4ff5 nohz: Align periodic tick Kconfig with other choices' naming convention
Rename CONFIG_PERIODIC_HZ to CONFIG_HZ_PERIODIC in
order to stay consistent with other tick implementation
entries:

	CONFIG_HZ_PERIODIC
	CONFIG_NO_HZ_IDLE
	CONFIG_NO_HZ_FULL

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-15 20:11:26 +02:00
Frederic Weisbecker
c5bfece2d6 nohz: Switch from "extended nohz" to "full nohz" based naming
"Extended nohz" was used as a naming base for the full dynticks
API and Kconfig symbols. It reflects the fact the system tries
to stop the tick in more places than just idle.

But that "extended" name is a bit opaque and vague. Rename it to
"full" makes it clearer what the system tries to do under this
config: try to shutdown the tick anytime it can. The various
constraints that prevent that to happen shouldn't be considered
as fundamental properties of this feature but rather technical
issues that may be solved in the future.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-15 19:58:17 +02:00
Frederic Weisbecker
0644ca5c77 nohz: Fix old dynticks idle Kconfig backward compatibility
In order to enforce backward compatibility with older
config files, we want the new dynticks-idle Kconfig entry
to default its value to the one of the old CONFIG_NO_HZ symbol
if present.

Namely we want:

	config NO_HZ # old obsolete dynticks idle symbol
		bool

	config NO_HZ_IDLE # new dynticks idle symbol
		default NO_HZ

However Kconfig prevents this to work if the old symbol
is not visible. And this is currently the case because
NO_HZ lacks a title in order to show it in make oldconfig
and alike.

To fix this, bring a minimal title and help text to the
obsolete Kconfig entry that explains its purpose. This
makes the "defaulting" to work.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-15 19:39:40 +02:00
Frederic Weisbecker
1034fc2f41 nohz: Print final full dynticks CPUs range on boot
Given that we apply a few restrictions on the full dynticks
CPUs range (keep an online timekeeper oustide the range,
then in the future have the range be an RCU nocb CPUs subset),
let's print the final resulting range of full dynticks CPUs to
the user so that he knows what's really going to run.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-03 14:00:48 +02:00
Frederic Weisbecker
3ca277e419 nohz: Pack nohz Kconfig option in a menu of choices
Now the user has the choice between three implementations of
the timer tick:

* Static periodic tick
* Idle dynticks
* Full dynticks

At least for now, these are mutually exclusive choices, so
let's rely on the proper Kconfig feature to display these
to the user.

A new entry CONFIG_NO_HZ_IDLE is created and the old
CONFIG_NO_HZ maps to it for config file backward compatibility.
The old name was too general now that we have more
granular dynticks implementations.

While at it, add some explanation to help the user on
his decision between the 3 entries.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-03 14:00:46 +02:00
Frederic Weisbecker
3451d0243c nohz: Rename CONFIG_NO_HZ to CONFIG_NO_HZ_COMMON
We are planning to convert the dynticks Kconfig options layout
into a choice menu. The user must be able to easily pick
any of the following implementations: constant periodic tick,
idle dynticks, full dynticks.

As this implies a mutual exclusion, the two dynticks implementions
need to converge on the selection of a common Kconfig option in order
to ease the sharing of a common infrastructure.

It would thus seem pretty natural to reuse CONFIG_NO_HZ to
that end. It already implements all the idle dynticks code
and the full dynticks depends on all that code for now.
So ideally the choice menu would propose CONFIG_NO_HZ_IDLE and
CONFIG_NO_HZ_EXTENDED then both would select CONFIG_NO_HZ.

On the other hand we want to stay backward compatible: if
CONFIG_NO_HZ is set in an older config file, we want to
enable CONFIG_NO_HZ_IDLE by default.

But we can't afford both at the same time or we run into
a circular dependency:

1) CONFIG_NO_HZ_IDLE and CONFIG_NO_HZ_EXTENDED both select
   CONFIG_NO_HZ
2) If CONFIG_NO_HZ is set, we default to CONFIG_NO_HZ_IDLE

We might be able to support that from Kconfig/Kbuild but it
may not be wise to introduce such a confusing behaviour.

So to solve this, create a new CONFIG_NO_HZ_COMMON option
which gathers the common code between idle and full dynticks
(that common code for now is simply the idle dynticks code)
and select it from their referring Kconfig.

Then we'll later create CONFIG_NO_HZ_IDLE and map CONFIG_NO_HZ
to it for backward compatibility.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-03 13:56:03 +02:00
Frederic Weisbecker
ab71d36ddb nohz: Unhide full dynticks feature from its dependencies
The full dynticks feature only shows up when all its
Kconfig dependencies are met (RCU nocbs, RCU user mode, ...)

This is far from being user friendly as those who want to
activate this feature need to look into the Kconfig files
and iterate through each dependency then activate these
by hand in order to show and select the full dynticks
Kconfig option.

So process the other way around: show up the Kconfig option
if the minimal low level dependencies are met and activate
the high level ones when we enable the feature.

Note there is one exception in the picture:
CONFIG_VIRT_CPU_ACCOUNTING_GEN is part of a Kconfig choice
menu and it appears we can't select it from another Kconfig
selection when it's under such layout. So for now this
particular item stays as a passive dependency.

Reported-by: Ingo Molnar <mingo@kernel.org>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-04-02 20:30:43 +02:00
Frederic Weisbecker
1c20091e77 nohz: Wake up full dynticks CPUs when a timer gets enqueued
Wake up a CPU when a timer list timer is enqueued there and
the target is part of the full dynticks range. Sending an IPI
to it makes it reconsidering the next timer to program on top
of recent updates.

This may later be improved by checking if the tick is really
stopped on the target. This would need some careful
synchronization though. So deal with such optimization later
and start simple.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-03-21 15:55:59 +01:00
Frederic Weisbecker
a382bf9344 nohz: Assign timekeeping duty to a CPU outside the full dynticks range
This way the full nohz CPUs can safely run with the tick
stopped with a guarantee that somebody else is taking
care of the jiffies and GTOD progression.

Once the duty is attributed to a CPU, it won't change. Also that
CPU can't enter into dyntick idle mode or be hot unplugged.

This may later be improved from a power consumption POV. At
least we should be able to share the duty amongst all CPUs
outside the full dynticks range. Then the duty could even be
shared with full dynticks CPUs when those can't stop their
tick for any reason.

But let's start with that very simple approach first.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
[fix have_nohz_full_mask offcase]
Signed-off-by: Steven Rostedt <rostedt@goodmis.org>
2013-03-21 15:55:45 +01:00
Frederic Weisbecker
a831881be2 nohz: Basic full dynticks interface
For extreme usecases such as Real Time or HPC, having
the ability to shutdown the tick when a single task runs
on a CPU is a desired feature:

* Reducing the amount of interrupts improves throughput
for CPU-bound tasks. The CPU is less distracted from its
real job, from an execution time and from the cache point
of views.

* This also improve latency response as we have less critical
sections.

Start with introducing a very simple interface to define
full dynticks CPU: use a boot time option defined cpumask
through the "nohz_extended=" kernel parameter. CPUs that
are part of this range will have their tick shutdown
whenever possible: provided they run a single task and
they don't do kernel activity that require the periodic
tick. These details will be later documented in
Documentation/*

An online CPU must be kept outside this range to handle the
timekeeping.

Suggested-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Chris Metcalf <cmetcalf@tilera.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: Geoff Levand <geoff@infradead.org>
Cc: Gilad Ben Yossef <gilad@benyossef.com>
Cc: Hakan Akkan <hakanakkan@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
2013-03-21 15:38:33 +01:00
Peter Zijlstra
a8d7ad52a7 sched/tracing: Allow tracing the preemption decision on wakeup
Thomas noted that we do the wakeup preemption check after the
wakeup trace point, this means the tracepoint cannot test/report
this decision; which is rather important for latency sensitive
workloads. Therefore move the tracepoint after doing the
preemption check.

Suggested-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
Acked-by: Paul Turner <pjt@google.com>
Cc: Mike Galbraith <efault@gmx.de>
Link: http://lkml.kernel.org/r/1363254519.26965.9.camel@laptop
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 10:18:08 +01:00
Ingo Molnar
e75c8b475e Merge branch 'sched/core' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core
Pull CPU runtime stats/accounting fixes from Frederic Weisbecker:

 " Some users are complaining that their threadgroup's runtime accounting
   freezes after a week or so of intense cpu-bound workload. This set tries
   to fix the issue by reducing the risk of multiplication overflow in the
   cputime scaling code. "

Stanislaw Gruszka further explained the historic context and impact of the
bug:

 " Commit 0cf55e1ec0 start to use scalling
   for whole thread group, so increase chances of hitting multiplication
   overflow, depending on how many CPUs are on the system.

   We have multiplication utime * rtime for one thread since commit
   b27f03d4bd.

   Overflow will happen after:

   rtime * utime > 0xffffffffffffffff jiffies

   if thread utilize 100% of CPU time, that gives:

   rtime > sqrt(0xffffffffffffffff) jiffies

   ritme > sqrt(0xffffffffffffffff) / (24 * 60 * 60 * HZ) days

   For HZ 100 it will be 497 days for HZ 1000 it will be 49 days.

   Bug affect only users, who run CPU intensive application for that
   long period. Also they have to be interested on utime,stime values,
   as bug has no other visible effect as making those values incorrect. "

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-18 10:09:31 +01:00
Andrei Epure
1bf08230f7 sched: Fix variable name misnomer, add comments
The min_vruntime variable actually stores the maximum value.
The added comment was taken from place_entity function.

Signed-off-by: Andrei Epure <epure.andrei@gmail.com>
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1363115544-1964-1-git-send-email-epure.andrei@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-14 08:22:29 +01:00
Frederic Weisbecker
d9a3c9823a sched: Lower chances of cputime scaling overflow
Some users have reported that after running a process with
hundreds of threads on intensive CPU-bound loads, the cputime
of the group started to freeze after a few days.

This is due to how we scale the tick-based cputime against
the scheduler precise execution time value.

We add the values of all threads in the group and we multiply
that against the sum of the scheduler exec runtime of the whole
group.

This easily overflows after a few days/weeks of execution.

A proposed solution to solve this was to compute that multiplication
on stime instead of utime:
   62188451f0
   ("cputime: Avoid multiplication overflow on utime scaling")

The rationale behind that was that it's easy for a thread to
spend most of its time in userspace under intensive CPU-bound workload
but it's much harder to do CPU-bound intensive long run in the kernel.

This postulate got defeated when a user recently reported he was still
seeing cputime freezes after the above patch. The workload that
triggers this issue relates to intensive networking workloads where
most of the cputime is consumed in the kernel.

To reduce much more the opportunities for multiplication overflow,
lets reduce the multiplication factors to the remainders of the division
between sched exec runtime and cputime. Assuming the difference between
these shouldn't ever be that large, it could work on many situations.

This gets the same results as in the upstream scaling code except for
a small difference: the upstream code always rounds the results to
the nearest integer not greater to what would be the precise result.
The new code rounds to the nearest integer either greater or not
greater. In practice this difference probably shouldn't matter but
it's worth mentioning.

If this solution appears not to be enough in the end, we'll
need to partly revert back to the behaviour prior to commit
     0cf55e1ec0
     ("sched, cputime: Introduce thread_group_times()")

Back then, the scaling was done on exit() time before adding the cputime
of an exiting thread to the signal struct. And then we'll need to
scale one-by-one the live threads cputime in thread_group_cputime(). The
drawback may be a slightly slower code on exit time.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Stanislaw Gruszka <sgruszka@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
2013-03-13 18:18:14 +01:00
Andrei Epure
660cc00f8c sched: Spelling fix
Signed-off-by: Andrei Epure <epure.andrei@gmail.com>
Cc: trivial@kernel.org
Cc: peterz@infradead.org
Link: http://lkml.kernel.org/r/1362996200-2674-1-git-send-email-epure.andrei@gmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-11 15:12:11 +01:00
Li Zefan
b719203b84 sched: Fix update_group_power() prototype placement to fix build warning when !CONFIG_SMP
All warnings:

   In file included from kernel/sched/core.c:85:0:
   kernel/sched/sched.h:1036:39: warning: 'struct sched_domain' declared inside parameter list
   kernel/sched/sched.h:1036:39: warning: its scope is only this definition or declaration, which is probably not what you want

It's because struct sched_domain is defined inside #if CONFIG_SMP,
while update_group_power() is declared unconditionally.

Fix this warning by declaring update_group_power() only if
CONFIG_SMP=n.

Build tested with CONFIG_SMP enabled and then disabled.

Reported-by: Fengguang Wu <fengguang.wu@intel.com>
Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5137F4BA.2060101@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-11 09:07:24 +01:00
Ingo Molnar
4e3da46797 Merge branch 'sched/cputime' of git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks into sched/core
Pull cputime changes from Frederic Weisbecker:

  * Generalize exception handling

  * Fix race in context tracking state restore on return from exception
    and irq exit kernel preemption

  * Fix cputime scaling in full dynticks accounting dynamic off-case

  * Fix default Kconfig value

Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-08 16:41:22 +01:00
Frederic Weisbecker
9fbc42eac1 cputime: Dynamically scale cputime for full dynticks accounting
The full dynticks cputime accounting is able to account either
using the tick or the context tracking subsystem. This way
the housekeeping CPU can keep the low overhead tick based
solution.

This latter mode has a low jiffies resolution granularity and
need to be scaled against CFS precise runtime accounting to
improve its result. We are doing this for CONFIG_TICK_CPU_ACCOUNTING,
now we also need to expand it to full dynticks accounting dynamic
off-case as well.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Mats Liljegren <mats.liljegren@enea.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-07 17:10:32 +01:00
Frederic Weisbecker
b22366cd54 context_tracking: Restore preempted context state after preempt_schedule_irq()
From the context tracking POV, preempt_schedule_irq() behaves pretty much
like an exception: It can be called anytime and schedule another task.

But currently it doesn't restore the context tracking state of the preempted
code on preempt_schedule_irq() return.

As a result, if preempt_schedule_irq() is called in the tiny frame between
user_enter() and the actual return to userspace, we resume userspace with
the wrong context tracking state.

Fix this by using exception_enter/exit() which are a perfect fit for this
kind of issue.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Li Zhong <zhong@linux.vnet.ibm.com>
Cc: Kevin Hilman <khilman@linaro.org>
Cc: Mats Liljegren <mats.liljegren@enea.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Namhyung Kim <namhyung.kim@lge.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
2013-03-07 17:10:21 +01:00
Li Zefan
27b4b9319a sched: Remove double declaration of root_task_group
It's already declared in include/linux/sched.h

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A7D8.7000107@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:35 +01:00
Li Zefan
25cc7da7e6 sched: Move group scheduling functions out of include/linux/sched.h
- Make sched_group_{set_,}runtime(), sched_group_{set_,}period()
and sched_rt_can_attach() static.

- Move sched_{create,destroy,online,offline}_group() to
kernel/sched/sched.h.

- Remove declaration of sched_group_shares().

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A7C5.3000708@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:34 +01:00
Li Zefan
15f803c94b sched: Make default_scale_freq_power() static
As default_scale_{freq,smt}_power() and update_rt_power() are
used in kernel/sched/fair.c only, annotate them as static
functions.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A7AF.8010900@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:34 +01:00
Li Zefan
c82ba9fa75 sched: Move struct sched_class to kernel/sched/sched.h
It's used internally only.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A79F.8090502@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:33 +01:00
Li Zefan
b13095f07f sched: Move wake flags to kernel/sched/sched.h
They are used internally only.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A78E.7040609@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:32 +01:00
Li Zefan
5e6521eaa1 sched: Move struct sched_group to kernel/sched/sched.h
Move struct sched_group_power and sched_group and related inline
functions to kernel/sched/sched.h, as they are used internally
only.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A77F.2010705@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:31 +01:00
Li Zefan
cc1f4b1f3f sched: Move SCHED_LOAD_SHIFT macros to kernel/sched/sched.h
They are used internally only.

Signed-off-by: Li Zefan <lizefan@huawei.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/5135A771.4070104@huawei.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2013-03-06 11:24:30 +01:00
Linus Torvalds
56a79b7b02 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs
Pull  more VFS bits from Al Viro:
 "Unfortunately, it looks like xattr series will have to wait until the
  next cycle ;-/

  This pile contains 9p cleanups and fixes (races in v9fs_fid_add()
  etc), fixup for nommu breakage in shmem.c, several cleanups and a bit
  more file_inode() work"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/vfs:
  constify path_get/path_put and fs_struct.c stuff
  fix nommu breakage in shmem.c
  cache the value of file_inode() in struct file
  9p: if v9fs_fid_lookup() gets to asking server, it'd better have hashed dentry
  9p: make sure ->lookup() adds fid to the right dentry
  9p: untangle ->lookup() a bit
  9p: double iput() in ->lookup() if d_materialise_unique() fails
  9p: v9fs_fid_add() can't fail now
  v9fs: get rid of v9fs_dentry
  9p: turn fid->dlist into hlist
  9p: don't bother with private lock in ->d_fsdata; dentry->d_lock will do just fine
  more file_inode() open-coded instances
  selinux: opened file can't have NULL or negative ->f_path.dentry

(In the meantime, the hlist traversal macros have changed, so this
required a semantic conflict fixup for the newly hlistified fid->dlist)
2013-03-03 13:23:03 -08:00
Linus Torvalds
8fd5e7a2d9 ImgTec Meta architecture changes for v3.9-rc1
This adds core architecture support for Imagination's Meta processor
 cores, followed by some later miscellaneous arch/metag cleanups and
 fixes which I kept separate to ease review:
 
  - Support for basic Meta 1 (ATP) and Meta 2 (HTP) core architecture
  - A few fixes all over, particularly for symbol prefixes
  - A few privilege protection fixes
  - Several cleanups (setup.c includes, split out a lot of metag_ksyms.c)
  - Fix some missing exports
  - Convert hugetlb to use vm_unmapped_area()
  - Copy device tree to non-init memory
  - Provide dma_get_sgtable()
 
 Signed-off-by: James Hogan <james.hogan@imgtec.com>
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Merge tag 'metag-v3.9-rc1-v4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag

Pull new ImgTec Meta architecture from James Hogan:
 "This adds core architecture support for Imagination's Meta processor
  cores, followed by some later miscellaneous arch/metag cleanups and
  fixes which I kept separate to ease review:

   - Support for basic Meta 1 (ATP) and Meta 2 (HTP) core architecture
   - A few fixes all over, particularly for symbol prefixes
   - A few privilege protection fixes
   - Several cleanups (setup.c includes, split out a lot of
     metag_ksyms.c)
   - Fix some missing exports
   - Convert hugetlb to use vm_unmapped_area()
   - Copy device tree to non-init memory
   - Provide dma_get_sgtable()"

* tag 'metag-v3.9-rc1-v4' of git://git.kernel.org/pub/scm/linux/kernel/git/jhogan/metag: (61 commits)
  metag: Provide dma_get_sgtable()
  metag: prom.h: remove declaration of metag_dt_memblock_reserve()
  metag: copy devicetree to non-init memory
  metag: cleanup metag_ksyms.c includes
  metag: move mm/init.c exports out of metag_ksyms.c
  metag: move usercopy.c exports out of metag_ksyms.c
  metag: move setup.c exports out of metag_ksyms.c
  metag: move kick.c exports out of metag_ksyms.c
  metag: move traps.c exports out of metag_ksyms.c
  metag: move irq enable out of irqflags.h on SMP
  genksyms: fix metag symbol prefix on crc symbols
  metag: hugetlb: convert to vm_unmapped_area()
  metag: export clear_page and copy_page
  metag: export metag_code_cache_flush_all
  metag: protect more non-MMU memory regions
  metag: make TXPRIVEXT bits explicit
  metag: kernel/setup.c: sort includes
  perf: Enable building perf tools for Meta
  metag: add boot time LNKGET/LNKSET check
  metag: add __init to metag_cache_probe()
  ...
2013-03-03 12:06:09 -08:00
Linus Torvalds
6ec40b4230 Merge branch 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal
Pull sigprocmask compat fix from Al Viro:
 "generic compat_sys_rt_sigprocmask() had a very dumb braino; I'd spent
  quite a while staring at the offending commit before finally managing
  to spot the idiocy ;-/"

* 'for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/viro/signal:
  fix compat_sys_rt_sigprocmask()
2013-03-02 19:32:06 -08:00
Al Viro
db61ec29fd fix compat_sys_rt_sigprocmask()
Converting bitmask to 32bit granularity is fine, but we'd better
_do_ something with the result.  Such as "copy it to userland"...

Signed-off-by: Al Viro <viro@zeniv.linux.org.uk>
2013-03-02 20:39:15 -05:00
James Hogan
649508f684 trace/ring_buffer: handle 64bit aligned structs
Some 32 bit architectures require 64 bit values to be aligned (for
example Meta which has 64 bit read/write instructions). These require 8
byte alignment of event data too, so use
!CONFIG_HAVE_64BIT_ALIGNED_ACCESS instead of !CONFIG_64BIT ||
CONFIG_HAVE_EFFICIENT_UNALIGNED_ACCESS to decide alignment, and align
buffer_data_page::data accordingly.

Signed-off-by: James Hogan <james.hogan@imgtec.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Ingo Molnar <mingo@redhat.com>
Acked-by: Steven Rostedt <rostedt@goodmis.org> (previous version subtly different)
2013-03-02 20:09:16 +00:00
Linus Torvalds
3cfb07743a KGDB/KDB fixes and cleanups
Cleanups
    Remove kdb ssb command - there is no in kernel disassembler to support it
    Remove kdb ll command - Always caused a kernel oops and there were no
        bug reports so no one was using this command
    Use kernel ARRAY_SIZE macro instead of array computations
 
  Fixes
    Stop oops in kdb if user executes kdb_defcmd with args
    kdb help command truncated text
    ppc64 support for kgdbts
    Add missing kconfig option from original kdb port for dealing with
       catastrophic kernel crashes such that you can reboot automatically
       on continue from kdb
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Merge tag 'for_linux-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb

Pull KGDB/KDB fixes and cleanups from Jason Wessel:
 "For a change we removed more code than we added.  If people aren't
  using it we shouldn't be carrying it.  :-)

  Cleanups:
   - Remove kdb ssb command - there is no in kernel disassembler to
     support it

   - Remove kdb ll command - Always caused a kernel oops and there were
     no bug reports so no one was using this command

   - Use kernel ARRAY_SIZE macro instead of array computations

  Fixes:
   - Stop oops in kdb if user executes kdb_defcmd with args

   - kdb help command truncated text

   - ppc64 support for kgdbts

   - Add missing kconfig option from original kdb port for dealing with
     catastrophic kernel crashes such that you can reboot automatically
     on continue from kdb"

* tag 'for_linux-3.9' of git://git.kernel.org/pub/scm/linux/kernel/git/jwessel/kgdb:
  kdb: Remove unhandled ssb command
  kdb: Prevent kernel oops with kdb_defcmd
  kdb: Remove the ll command
  kdb_main: fix help print
  kdb: Fix overlap in buffers with strcpy
  Fixed dead ifdef block by adding missing Kconfig option.
  kdb: Setup basic kdb state before invoking commands via kgdb
  kdb: use ARRAY_SIZE where possible
  kgdb/kgdbts: support ppc64
  kdb: A fix for kdb command table expansion
2013-03-02 08:31:39 -08:00
Linus Torvalds
e23b62256a Initial ARC Linux port with some fixes on top for 3.9-rc1
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Merge tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc

Pull new ARC architecture from Vineet Gupta:
 "Initial ARC Linux port with some fixes on top for 3.9-rc1:

  I would like to introduce the Linux port to ARC Processors (from
  Synopsys) for 3.9-rc1.  The patch-set has been discussed on the public
  lists since Nov and has received a fair bit of review, specially from
  Arnd, tglx, Al and other subsystem maintainers for DeviceTree, kgdb...

  The arch bits are in arch/arc, some asm-generic changes (acked by
  Arnd), a minor change to PARISC (acked by Helge).

  The series is a touch bigger for a new port for 2 main reasons:

   1. It enables a basic kernel in first sub-series and adds
      ptrace/kgdb/.. later

   2. Some of the fallout of review (DeviceTree support, multi-platform-
      image support) were added on top of orig series, primarily to
      record the revision history.

  This updated pull request additionally contains

   - fixes due to our GNU tools catching up with the new syscall/ptrace
     ABI

   - some (minor) cross-arch Kconfig updates."

* tag 'arc-v3.9-rc1-late' of git://git.kernel.org/pub/scm/linux/kernel/git/vgupta/arc: (82 commits)
  ARC: split elf.h into uapi and export it for userspace
  ARC: Fixup the current ABI version
  ARC: gdbserver using regset interface possibly broken
  ARC: Kconfig cleanup tracking cross-arch Kconfig pruning in merge window
  ARC: make a copy of flat DT
  ARC: [plat-arcfpga] DT arc-uart bindings change: "baud" => "current-speed"
  ARC: Ensure CONFIG_VIRT_TO_BUS is not enabled
  ARC: Fix pt_orig_r8 access
  ARC: [3.9] Fallout of hlist iterator update
  ARC: 64bit RTSC timestamp hardware issue
  ARC: Don't fiddle with non-existent caches
  ARC: Add self to MAINTAINERS
  ARC: Provide a default serial.h for uart drivers needing BASE_BAUD
  ARC: [plat-arcfpga] defconfig for fully loaded ARC Linux
  ARC: [Review] Multi-platform image #8: platform registers SMP callbacks
  ARC: [Review] Multi-platform image #7: SMP common code to use callbacks
  ARC: [Review] Multi-platform image #6: cpu-to-dma-addr optional
  ARC: [Review] Multi-platform image #5: NR_IRQS defined by ARC core
  ARC: [Review] Multi-platform image #4: Isolate platform headers
  ARC: [Review] Multi-platform image #3: switch to board callback
  ...
2013-03-02 07:58:56 -08:00
Vincent
36dfea42cc kdb: Remove unhandled ssb command
The 'ssb' command can only be handled when we have a disassembler, to check for
branches, so remove the 'ssb' command for now.

Signed-off-by: Vincent Stehlé <vincent.stehle@laposte.net>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:20 -06:00
Jason Wessel
a37372f6c3 kdb: Prevent kernel oops with kdb_defcmd
The kdb_defcmd can only be used to display the available command aliases
while using the kernel debug shell.  If you try to define a new macro
while the kernel debugger is active it will oops.  The debug shell
macros must use pre-allocated memory set aside at the time kdb_init()
is run, and the kdb_defcmd is restricted to only working at the time
that the kdb_init sequence is being run, which only occurs if you
actually activate the kernel debugger.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:19 -06:00
Jason Wessel
1b2caa2dcb kdb: Remove the ll command
Recently some code inspection was done after fixing a problem with
kmalloc used while in the kernel debugger context (which is not
legal), and it turned up the fact that kdb ll command will oops the
kernel.

Given that there have been zero bug reports on the command combined
with the fact it will oops the kernel it is clearly not being used.
Instead of fixing it, it will be removed.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:19 -06:00
Jason Wessel
074604af21 kdb_main: fix help print
The help command was chopping all the usage instructions such that
they were not readable.

Example:

bta             [D|R|S|T|C|Z|E|U|I| Backtrace all processes matching state flag
per_cpu         <sym> [<bytes>] [<c Display per_cpu variables

Where as it should look like:

bta             [D|R|S|T|C|Z|E|U|I|M|A]
                                    Backtrace all processes matching state flag
per_cpu         <sym> [<bytes>] [<cpu>]
                                    Display per_cpu variables

All that is needed is to check the how long the cmd_usage is and jump
to the next line when appropriate.

Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:18 -06:00
Jason Wessel
4eb7a66d94 kdb: Fix overlap in buffers with strcpy
Maxime reported that strcpy(s->usage, s->usage+1) has no definitive
guarantee that it will work on all archs the same way when you have
overlapping memory.  The fix is simple for the kdb code because we
still have the original string memory in the function scope, so we
just have to use that as the argument instead.

Reported-by: Maxime Villard <rustyBSD@gmx.fr>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:18 -06:00
Matt Klein
00370b8f8d kdb: Setup basic kdb state before invoking commands via kgdb
Although invasive kdb commands are not supported via kgdb, some useful
non-invasive commands like bt* require basic kdb state to be setup before
calling into the kdb code. Factor out some of this code and call it before
and after executing kdb commands via kgdb.

Signed-off-by: Matt Klein <mklein@twitter.com>
Signed-off-by: Jason Wessel <jason.wessel@windriver.com>
2013-03-02 08:52:17 -06:00