When showing pid to user or getting the pid numerical id for in-kernel use the
value of this id may differ depending on the namespace.

This set of helpers is used to get the global pid nr, the virtual (i.e.  seen
by task in its namespace) nr and the nr as it is seen from the specified
namespace.
Signed-off-by: NPavel Emelyanov <xemul@openvz.org>
Cc: Oleg Nesterov <oleg@tv-sign.ru>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Cc: Paul Menage <menage@google.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

is_init() is an ambiguous name for the pid==1 check.  Split it into
is_global_init() and is_container_init().

A cgroup init has it's tsk->pid == 1.

A global init also has it's tsk->pid == 1 and it's active pid namespace
is the init_pid_ns.  But rather than check the active pid namespace,
compare the task structure with 'init_pid_ns.child_reaper', which is
initialized during boot to the /sbin/init process and never changes.

Changelog:

	2.6.22-rc4-mm2-pidns1:
	- Use 'init_pid_ns.child_reaper' to determine if a given task is the
	  global init (/sbin/init) process. This would improve performance
	  and remove dependence on the task_pid().

	2.6.21-mm2-pidns2:

	- [Sukadev Bhattiprolu] Changed is_container_init() calls in {powerpc,
	  ppc,avr32}/traps.c for the _exception() call to is_global_init().
	  This way, we kill only the cgroup if the cgroup's init has a
	  bug rather than force a kernel panic.

[akpm@linux-foundation.org: fix comment]
[sukadev@us.ibm.com: Use is_global_init() in arch/m32r/mm/fault.c]
[bunk@stusta.de: kernel/pid.c: remove unused exports]
[sukadev@us.ibm.com: Fix capability.c to work with threaded init]
Signed-off-by: NSerge E. Hallyn <serue@us.ibm.com>
Signed-off-by: NSukadev Bhattiprolu <sukadev@us.ibm.com>
Acked-by: NPavel Emelianov <xemul@openvz.org>
Cc: Eric W. Biederman <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Herbert Poetzel <herbert@13thfloor.at>
Cc: Kirill Korotaev <dev@sw.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

The set of functions process_session, task_session, process_group and
task_pgrp is confusing, as the names can be mixed with each other when looking
at the code for a long time.

The proposals are to
* equip the functions that return the integer with _nr suffix to
  represent that fact,
* and to make all functions work with task (not process) by making
  the common prefix of the same name.

For monotony the routines signal_session() and set_signal_session() are
replaced with task_session_nr() and set_task_session(), especially since they
are only used with the explicit task->signal dereference.
Signed-off-by: NPavel Emelianov <xemul@openvz.org>
Acked-by: NSerge E. Hallyn <serue@us.ibm.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Sukadev Bhattiprolu <sukadev@us.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Remove the filesystem support logic from the cpusets system and makes cpusets
a cgroup subsystem

The "cpuset" filesystem becomes a dummy filesystem; attempts to mount it get
passed through to the cgroup filesystem with the appropriate options to
emulate the old cpuset filesystem behaviour.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Replace the struct css_set embedded in task_struct with a pointer; all tasks
that have the same set of memberships across all hierarchies will share a
css_set object, and will be linked via their css_sets field to the "tasks"
list_head in the css_set.

Assuming that many tasks share the same cgroup assignments, this reduces
overall space usage and keeps the size of the task_struct down (three pointers
added to task_struct compared to a non-cgroups kernel, no matter how many
subsystems are registered).

[akpm@linux-foundation.org: fix a printk]
[akpm@linux-foundation.org: build fix]
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Generic Process Control Groups
--------------------------

There have recently been various proposals floating around for
resource management/accounting and other task grouping subsystems in
the kernel, including ResGroups, User BeanCounters, NSProxy
cgroups, and others.  These all need the basic abstraction of being
able to group together multiple processes in an aggregate, in order to
track/limit the resources permitted to those processes, or control
other behaviour of the processes, and all implement this grouping in
different ways.

This patchset provides a framework for tracking and grouping processes
into arbitrary "cgroups" and assigning arbitrary state to those
groupings, in order to control the behaviour of the cgroup as an
aggregate.

The intention is that the various resource management and
virtualization/cgroup efforts can also become task cgroup
clients, with the result that:

- the userspace APIs are (somewhat) normalised

- it's easier to test e.g. the ResGroups CPU controller in
 conjunction with the BeanCounters memory controller, or use either of
them as the resource-control portion of a virtual server system.

- the additional kernel footprint of any of the competing resource
 management systems is substantially reduced, since it doesn't need
 to provide process grouping/containment, hence improving their
 chances of getting into the kernel

This patch:

Add the main task cgroups framework - the cgroup filesystem, and the
basic structures for tracking membership and associating subsystem state
objects to tasks.
Signed-off-by: NPaul Menage <menage@google.com>
Cc: Serge E. Hallyn <serue@us.ibm.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Dave Hansen <haveblue@us.ibm.com>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Paul Jackson <pj@sgi.com>
Cc: Kirill Korotaev <dev@openvz.org>
Cc: Herbert Poetzl <herbert@13thfloor.at>
Cc: Srivatsa Vaddagiri <vatsa@in.ibm.com>
Cc: Cedric Le Goater <clg@fr.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds items to the taststats struct to account for user and system
time based on scaling the CPU frequency and instruction issue rates.

Adds account_(user|system)_time_scaled callbacks which architectures
can use to account for time using this mechanism.
Signed-off-by: NMichael Neuling <mikey@neuling.org>
Cc: Balbir Singh <balbir@in.ibm.com>
Cc: Jay Lan <jlan@engr.sgi.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Hell knows what happened in commit 63b05203af57e7de4f3bb63b8b81d43bc196d32b
during 2.6.9 development.  Commit introduced io_wait field which remained
write-only than and still remains write-only.

Also garbage collect macros which "use" io_wait.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

schedstat is useful in investigating CPU scheduler behavior.  Ideally,
I think it is beneficial to have it on all the time.  However, the
cost of turning it on in production system is quite high, largely due
to number of events it collects and also due to its large memory
footprint.

Most of the fields probably don't need to be full 64-bit on 64-bit
arch.  Rolling over 4 billion events will most like take a long time
and user space tool can be made to accommodate that.  I'm proposing
kernel to cut back most of variable width on 64-bit system.  (note,
the following patch doesn't affect 32-bit system).
Signed-off-by: NKen Chen <kenchen@google.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

For those who don't care about CONFIG_SECURITY.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Cc: "Serge E. Hallyn" <serge@hallyn.com>
Cc: Casey Schaufler <casey@schaufler-ca.com>
Cc: James Morris <jmorris@namei.org>
Cc: Stephen Smalley <sds@tycho.nsa.gov>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

There is nice 2 byte hole after struct task_struct::ioprio field
into which we can put two 1-byte fields: ->fpu_counter and ->oomkilladj.
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Acked-by: NArjan van de Ven <arjan@infradead.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

For those who deselect POSIX message queues.

Reduces SLAB size of user_struct from 64 to 32 bytes here, SLUB size -- from
40 bytes to 32 bytes.

[akpm@linux-foundation.org: fix build]
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

robust_list, compat_robust_list, pi_state_list, pi_state_cache are
really used if futexes are on.
Signed-off-by: NAlexey Dobriyan <adobriyan@sw.ru>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

oomkilladj is int, but values which can be assigned to it are -17, [-16,
15], thus fitting into s8.

While patch itself doesn't help in making task_struct smaller, because of
natural alignment of ->link_count, it will make picture clearer wrt futher
task_struct reduction patches.  My plan is to move ->fpu_counter and
->oomkilladj after ->ioprio filling hole on i386 and x86_64.  But that's
for later, because bloated distro configs need looking at as well.
Signed-off-by: NAlexey Dobriyan <adobriyan@gmail.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

This adds the MMF_DUMP_ELF_HEADERS option to /proc/pid/coredump_filter.
This dumps the first page (only) of a private file mapping if it appears to
be a mapping of an ELF file.  Including these pages in the core dump may
give sufficient identifying information to associate the original DSO and
executable file images and their debugging information with a core file in
a generic way just from its contents (e.g.  when those binaries were built
with ld --build-id).  I expect this to become the default behavior
eventually.  Existing versions of gdb can be confused by the core dumps it
creates, so it won't enabled by default for some time to come.  Soon many
people will have systems with a gdb that handle these dumps, so they can
arrange to set the bit at boot and have it inherited system-wide.

This also cleans up the checking of the MMF_DUMP_* flag bits, which did not
need to be using atomic macros.
Signed-off-by: NRoland McGrath <roland@redhat.com>
Cc: Hidehiro Kawai <hidehiro.kawai.ez@hitachi.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Control the trigger limit for softlockup warnings.  This is useful for
debugging softlockups, by lowering the softlockup_thresh to identify
possible softlockups earlier.

This patch:
1. Adds a sysctl softlockup_thresh with valid values of 1-60s
   (Higher value to disable false positives)
2. Changes the softlockup printk to print the cpu softlockup time

[akpm@linux-foundation.org: Fix various warnings and add definition of "two"]
Signed-off-by: NRavikiran Thirumalai <kiran@scalex86.org>
Signed-off-by: NShai Fultheim <shai@scalex86.org>
Acked-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Based on ideas of Andrew:
  http://marc.info/?l=linux-kernel&m=102912915020543&w=2

Scale the bdi dirty limit inversly with the tasks dirty rate.
This makes heavy writers have a lower dirty limit than the occasional writer.

Andrea proposed something similar:
  http://lwn.net/Articles/152277/

The main disadvantage to his patch is that he uses an unrelated quantity to
measure time, which leaves him with a workload dependant tunable. Other than
that the two approaches appear quite similar.

[akpm@linux-foundation.org: fix warning]
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

When CONFIG_SYSFS is not set, CONFIG_FAIR_USER_SCHED fails to build
with

kernel/built-in.o: In function `uids_kobject_init':
(.init.text+0x1488): undefined reference to `kernel_subsys'
kernel/built-in.o: In function `uids_kobject_init':
(.init.text+0x1490): undefined reference to `kernel_subsys'
kernel/built-in.o: In function `uids_kobject_init':
(.init.text+0x1480): undefined reference to `kernel_subsys'
kernel/built-in.o: In function `uids_kobject_init':
(.init.text+0x1494): undefined reference to `kernel_subsys'

This patch fixes this build error.
Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Remove the cpuset hooks that defined sched domains depending on the setting
of the 'cpu_exclusive' flag.

The cpu_exclusive flag can only be set on a child if it is set on the
parent.

This made that flag painfully unsuitable for use as a flag defining a
partitioning of a system.

It was entirely unobvious to a cpuset user what partitioning of sched
domains they would be causing when they set that one cpu_exclusive bit on
one cpuset, because it depended on what CPUs were in the remainder of that
cpusets siblings and child cpusets, after subtracting out other
cpu_exclusive cpusets.

Furthermore, there was no way on production systems to query the
result.

Using the cpu_exclusive flag for this was simply wrong from the get go.

Fortunately, it was sufficiently borked that so far as I know, almost no
successful use has been made of this.  One real time group did use it to
affectively isolate CPUs from any load balancing efforts.  They are willing
to adapt to alternative mechanisms for this, such as someway to manipulate
the list of isolated CPUs on a running system.  They can do without this
present cpu_exclusive based mechanism while we develop an alternative.

There is a real risk, to the best of my understanding, of users
accidentally setting up a partitioned scheduler domains, inhibiting desired
load balancing across all their CPUs, due to the nonobvious (from the
cpuset perspective) side affects of the cpu_exclusive flag.

Furthermore, since there was no way on a running system to see what one was
doing with sched domains, this change will be invisible to any using code.
Unless they have real insight to the scheduler load balancing choices, they
will be unable to detect that this change has been made in the kernel's
behaviour.

Initial discussion on lkml of this patch has generated much comment.  My
(probably controversial) take on that discussion is that it has reached a
rough concensus that the current cpuset cpu_exclusive mechanism for
defining sched domains is borked.  There is no concensus on the
replacement.  But since we can remove this mechanism, and since its
continued presence risks causing unwanted partitioning of the schedulers
load balancing, we should remove it while we can, as we proceed to work the
replacement scheduler domain mechanisms.
Signed-off-by: NPaul Jackson <pj@sgi.com>
Cc: Ingo Molnar <mingo@elte.hu>
Cc: Nick Piggin <nickpiggin@yahoo.com.au>
Cc: Christoph Lameter <clameter@engr.sgi.com>
Cc: Dinakar Guniguntala <dino@in.ibm.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

Move the definitions of struct mm_struct and struct vma_area_struct to
include/mm_types.h.  This allows to define more function in asm/pgtable.h
and friends with inline assemblies instead of macros.  Compile tested on
i386, powerpc, powerpc64, s390-32, s390-64 and x86_64.

[aurelien@aurel32.net: build fix]
Signed-off-by: NMartin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: NAurelien Jarno <aurelien@aurel32.net>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>

modify account_system_time() to add cputime to cpustat->guest if we are
running a VCPU. We add this cputime to cpustat->user instead of
cpustat->system because this part of KVM code is in fact user code
although it is executed in the kernel. We duplicate VCPU time between
guest and user to allow an unmodified "top(1)" to display correct value.
A modified "top(1)" is able to display good cpu user time and cpu guest
time by subtracting cpu guest time from cpu user time. Update "gtime" in
task_struct accordingly.
Signed-off-by: NLaurent Vivier <Laurent.Vivier@bull.net>
Acked-by: NAvi Kivity <avi@qumranet.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

like for cpustat, introduce the "gtime" (guest time of the task) and
"cgtime" (guest time of the task children) fields for the
tasks. Modify signal_struct and task_struct.

Modify /proc/<pid>/stat to display these new fields.
Signed-off-by: NLaurent Vivier <Laurent.Vivier@bull.net>
Acked-by: NAvi Kivity <avi@qumranet.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

add new migration statistics when SCHED_DEBUG and SCHEDSTATS
is enabled. Available in /proc/<PID>/sched.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

reintroduce a simplified version of cache-hot/cold scheduling
affinity. This improves performance with certain SMP workloads,
such as sysbench.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Prevent wakeup over-scheduling.  Once a task has been preempted by a
task of the same or lower priority, it becomes ineligible for repeated
preemption by same until it has been ticked, or slept.  Instead, the
task is marked for preemption at the next tick.  Tasks of higher
priority still preempt immediately.
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Add tunables in sysfs to modify a user's cpu share.

A directory is created in sysfs for each new user in the system.

	/sys/kernel/uids/<uid>/cpu_share

Reading this file returns the cpu shares granted for the user.
Writing into this file modifies the cpu share for the user. Only an
administrator is allowed to modify a user's cpu share.

Ex:
	# cd /sys/kernel/uids/
	# cat 512/cpu_share
	1024
	# echo 2048 > 512/cpu_share
	# cat 512/cpu_share
	2048
	#
Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

cleanup: rename task_grp to task_group. No need to save two characters
and 'grp' is annoying to read.
Signed-off-by: NIngo Molnar <mingo@elte.hu>

Here's another piece of low hanging obsolete fruit.

Remove obsolete TASK_NONINTERACTIVE.
Signed-off-by: NMike Galbraith <efault@gmx.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

mark scheduling classes as const. The speeds up the code
a bit and shrinks it:

   text    data     bss     dec     hex filename
  40027    4018     292   44337    ad31 sched.o.before
  40190    3842     292   44324    ad24 sched.o.after
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

speed up and simplify vslice calculations.

[ From: Mike Galbraith <efault@gmx.de>: build fix ]
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

rename all 'cnt' fields and variables to the less yucky 'count' name.

yuckage noticed by Andrew Morton.

no change in code, other than the /proc/sched_debug bkl_count string got
a bit larger:

   text    data     bss     dec     hex filename
  38236    3506      24   41766    a326 sched.o.before
  38240    3506      24   41770    a32a sched.o.after
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

undo some of the recent changes that are not needed after all,
such as last_min_vruntime.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>

add vslice: the load-dependent "virtual slice" a task should
run ideally, so that the observed latency stays within the
sched_latency window.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

remove unneeded tunables.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

add per task and per rq BKL usage statistics.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

Enable user-id based fair group scheduling. This is useful for anyone
who wants to test the group scheduler w/o having to enable
CONFIG_CGROUPS.

A separate scheduling group (i.e struct task_grp) is automatically created for 
every new user added to the system. Upon uid change for a task, it is made to 
move to the corresponding scheduling group.

A /proc tunable (/proc/root_user_share) is also provided to tune root
user's quota of cpu bandwidth.
Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

With the view of supporting user-id based fair scheduling (and not just
container-based fair scheduling), this patch renames several functions
and makes them independent of whether they are being used for container
or user-id based fair scheduling.

Also fix a problem reported by KAMEZAWA Hiroyuki (wrt allocating
less-sized array for tg->cfs_rq[] and tf->se[]).
Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

Revert removal of set_curr_task.
Use put_prev_task/set_curr_task when changing groups/policies

Signed-off-by: Srivatsa Vaddagiri < vatsa@linux.vnet.ibm.com>
Signed-off-by: NDhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>

rework enqueue/dequeue_entity() to get rid of 
sched_class::set_curr_task(). This simplifies sched_setscheduler(), 
rt_mutex_setprio() and sched_move_tasks().

   text    data     bss     dec     hex filename
  24330    2734      20   27084    69cc sched.o.before
  24233    2730      20   26983    6967 sched.o.after
Signed-off-by: NDmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: NSrivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>

the 'p' (task_struct) parameter in the sched_class :: yield_task() is
redundant as the caller is always the 'current'. Get rid of it.

   text    data     bss     dec     hex filename
  24341    2734      20   27095    69d7 sched.o.before
  24330    2734      20   27084    69cc sched.o.after
Signed-off-by: NDmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: NThomas Gleixner <tglx@linutronix.de>