sched: domain sysctl fixes: add terminator comment

we had an incorrect-terminator bug in sd_alloc_ctl_domain_table()
before, so add a comment that documents it.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: domain sysctl fixes: do not crash on allocation failure

Now that we are calling this at runtime, a more relaxed error path is
suggested.  If an allocation fails, we just register the partial table,
which will show empty directories.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: domain sysctl fixes: unregister the sysctl table before domains

Unregister and free the sysctl table before destroying domains, then
rebuild and register after creating the new domains.  This prevents the
sysctl table from pointing to freed memory for root to write.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: domain sysctl fixes: use for_each_online_cpu()

init_sched_domain_sysctl was walking cpus 0-n and referencing per_cpu
variables.  If the cpus_possible mask is not contigious this will result
in a crash referencing unallocated data.  If the online mask is not
contigious then we would show offline cpus and miss online ones.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: domain sysctl fixes: use kcalloc()

kcalloc checks for n * sizeof(element) overflows and it zeros.

Signed-off-by: Milton Miller <miltonm@bga.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

Make scheduler debug file operations const

In general, struct file_operations are const in the kernel, to not have
false cacheline sharing and to catch bugs at compiletime with accidental
writes to them. The new scheduler code introduces a new non-const one;
fix this up.

Signed-off-by: Arjan van de Ven <arjan@linux.intel.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: enable wake-idle on CONFIG_SCHED_MC=y

most multicore CPUs today have shared L2 caches, so tune things so
that the spreading amongst cores is more aggressive.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: reintroduce topology.h tunings

reintroduce the 2.6.22 topology.h tunings again - they result in
slightly better balancing.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: allow the immediate migration of cache-cold tasks

allow the immediate migration of cache-cold tasks.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: debug, improve migration statistics

add new migration statistics when SCHED_DEBUG and SCHEDSTATS
is enabled. Available in /proc/<PID>/sched.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: debug: increase width of debug line

increase width of debug line - in preparation of more debugging info.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: activate task_hot() only on fair-scheduled tasks

activate task_hot() only for fair-scheduled tasks (i.e. disable it
for RT tasks).

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: reintroduce cache-hot affinity

reintroduce a simplified version of cache-hot/cold scheduling
affinity. This improves performance with certain SMP workloads,
such as sysbench.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: speed up context-switches a bit

speed up context-switches a bit by not clearing p->exec_start.

(as a side-effect, this also makes p->exec_start a universal timestamp
available to cache-hot estimations.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: do not wakeup-preempt with SCHED_BATCH tasks

do not wakeup-preempt with SCHED_BATCH tasks, their preemption
is batched too, driven by the tick.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: generate uevents for user creation/destruction

Generate uevents when a user is being created/destroyed. These events
can be used to configure cpu share of a new user.

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: do not normalize kernel threads via SysRq-N

do not normalize kernel threads via SysRq-N: the migration threads,
softlockup threads, etc. might be essential for the system to
function properly. So only zap user tasks.

pointed out by Andi Kleen.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: remove stale comment from sched_group_set_shares()

remove stale comment from sched_group_set_shares().

Function never returns -EINVAL.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: clean up is_migration_thread()

clean up is_migration_thread() and turn it into an inline function.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup: refactor normalize_rt_tasks

Replace a particularly ugly ifdef with an inline and a new macro.
Also split up the function to be easier to read.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup: refactor common code of sleep_on / wait_for_completion

Refactor common code of sleep_on / wait_for_completion

These functions were largely cut'n'pasted. This moves
the common code into single helpers instead.  Advantage
is about 1k less code on x86-64 and 91 lines of code removed.
It adds one function call to the non timeout version of
the functions; i don't expect this to be measurable.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup: remove unnecessary gotos

Replace loops implemented with gotos with real loops.
Replace err = ...; goto x; x: return err; with return ...;

No functional changes.

Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: update comment

update comment: clarify time-slices and remove obsolete tuning detail.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: prevent wakeup over-scheduling

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: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: disable forced preemption by default

Implement feature bit to disable forced preemption. This way
it can be checked whether a workload is overscheduling or not.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: fix group scheduling for SCHED_BATCH

The following patch (sched: disable sleeper_fairness on SCHED_BATCH)
seems to break GROUP_SCHED. Although, it may be 'oops'-less due to the
possibility of 'p' being always a valid address.

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: some proc entries are missed in sched_domain sys_ctl debug code

cache_nice_tries and flags entry do not appear in proc fs sched_domain
directory, because ctl_table entry is skipped.

This patch fixes the issue.

Signed-off-by: Zou Nan hai <nanhai.zou@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: fix rt ptracer monopolizing CPU

yield() in wait_task_inactive(), can cause a high priority thread to be
scheduled back in, and there by loop forever while it is waiting for some
lower priority thread which is unfortunately still on the runqueue.

Use schedule_timeout_uninterruptible(1) instead.

Signed-off-by: Gautham R Shenoy <ego@in.ibm.com>
Credit: Oleg Nesterov <oleg@tv-sign.ru>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: group scheduling, sysfs tunables

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: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: disable sleeper_fairness on SCHED_BATCH

disable sleeper fairness for batch tasks - they are about
batch processing after all.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: another wakeup_granularity fix

unit mis-match: wakeup_gran was used against a vruntime

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: export cpu_clock()

export cpu_clock() - the preferred API instead of sched_clock().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: fix: move the CPU check into ->task_new_fair()

noticed by Peter Zijlstra:

fix: move the CPU check into ->task_new_fair(), this way we
can call place_entity() and get child ->vruntime right at
initial wakeup time.

(without this there can be large latencies)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: cleanup: function prototype cleanups

noticed by Thomas Gleixner:

cleanup: function prototype cleanups - move into single line
wherever possible.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup: rename task_grp to task_group

cleanup: rename task_grp to task_group. No need to save two characters
and 'grp' is annoying to read.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup: rename SCHED_FEAT_USE_TREE_AVG to SCHED_FEAT_TREE_AVG

cleanup: rename SCHED_FEAT_USE_TREE_AVG to SCHED_FEAT_TREE_AVG, to
make SCHED_FEAT_ names more consistent.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: kfree(NULL) is valid

kfree(NULL) is valid.

pointed out by checkpatch.pl.

the fix shrinks the code a bit:

   text    data     bss     dec     hex filename
  40024    3842     100   43966    abbe sched.o.before
  40002    3842     100   43944    aba8 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: style cleanup

fix up __setup() style bug - noticed via checkpatch.pl.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: break out if printing a warning in sched_domain_debug()

checkpatch.pl and Andy Whitcroft noticed the following bug: we did
not break out after printing an error.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: run sched_domain_debug() if CONFIG_SCHED_DEBUG=y

run sched_domain_debug() if CONFIG_SCHED_DEBUG=y, instead
of relying on the hand-crafted SCHED_DOMAIN_DEBUG switch.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup, remove the TASK_NONINTERACTIVE flag

Here's another piece of low hanging obsolete fruit.

Remove obsolete TASK_NONINTERACTIVE.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup, make dequeue_entity() and update_stats_wait_end() similar

make dequeue_entity() / enqueue_entity() and update_stats_dequeue() /
update_stats_enqueue() look similar, structure-wise.

zero effect, functionality-wise:

   text    data     bss     dec     hex filename
  34550    3026     100   37676    932c sched.o.before
  34550    3026     100   37676    932c sched.o.after

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: cleanup, remove calc_weighted()

remove obsolete code -- calc_weighted()

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: tidy up SCHED_RR

- make timeslices of SCHED_RR tasks constant and not
dependent on task's static_prio [1] ;
- remove obsolete code (timeslice related bits);
- make sched_rr_get_interval() return something more
meaningful [2] for SCHED_OTHER tasks.

[1] according to the following link, it's not compliant with SUSv3
(not sure though, what is the reference for us :-)
http://lkml.org/lkml/2007/3/7/656

[2] the interval is dynamic and can be depicted as follows "should a
task be one of the runnable tasks at this particular moment, it would
expect to run for this interval of time before being re-scheduled by the
scheduler tick".
(i.e. it's more precise if a task is runnable at the moment)

yeah, this seems to require task_rq_lock/unlock() but this is not a hot
path.

results:

(SCHED_FIFO)

dimm@earth:~/storage/prog$ sudo chrt -f 10 ./rr_interval
time_slice: 0 : 0

(SCHED_RR)

dimm@earth:~/storage/prog$ sudo chrt 10 ./rr_interval
time_slice: 0 : 99984800

(SCHED_NORMAL)

dimm@earth:~/storage/prog$ ./rr_interval
time_slice: 0 : 19996960

(SCHED_NORMAL + a cpu_hog of similar 'weight' on the same CPU --- so should be a half of the previous result)

dimm@earth:~/storage/prog$ taskset 1 ./rr_interval
time_slice: 0 : 9998480

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: uninline scheduler

* save ~300 bytes
* activate_idle_task() was moved to avoid a warning

bloat-o-meter output:

add/remove: 6/0 grow/shrink: 0/16 up/down: 438/-733 (-295) <===
function                                     old     new   delta
__enqueue_entity                               -     165    +165
finish_task_switch                             -     110    +110
update_curr_rt                                 -      79     +79
__load_balance_iterator                        -      32     +32
__task_rq_unlock                               -      28     +28
find_process_by_pid                            -      24     +24
do_sched_setscheduler                        133     123     -10
sys_sched_rr_get_interval                    176     165     -11
sys_sched_getparam                           156     145     -11
normalize_rt_tasks                           482     470     -12
sched_getaffinity                            112      99     -13
sys_sched_getscheduler                        86      72     -14
sched_setaffinity                            226     212     -14
sched_setscheduler                           666     642     -24
load_balance_start_fair                       33       9     -24
load_balance_next_fair                        33       9     -24
dequeue_task_rt                              133      67     -66
put_prev_task_rt                              97      28     -69
schedule_tail                                133      50     -83
schedule                                     682     594     -88
enqueue_entity                               499     366    -133
task_new_fair                                317     180    -137

Signed-off-by: Alexey Dobriyan <adobriyan@sw.ru>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: tweak wakeup granularity

tweak wakeup granularity.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: optimize schedule() a bit on SMP

optimize schedule() a bit on SMP, by moving the rq-clock update
outside the rq lock.

code size is the same:

      text    data     bss     dec     hex filename
     25725    2666      96   28487    6f47 sched.o.before
     25725    2666      96   28487    6f47 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: fix __pick_next_entity()

The thing is that __pick_next_entity() must never be called when
first_fair(cfs_rq) == NULL. It wouldn't be a problem, should 'run_node'
be the very first field of 'struct sched_entity' (and it's the second).

The 'nr_running != 0' check is _not_ enough, due to the fact that
'current' is not within the tree. Generic paths are ok (e.g. schedule()
as put_prev_task() is called previously)... I'm more worried about e.g.
migration_call() -> CPU_DEAD_FROZEN -> migrate_dead_tasks()... if
'current' == rq->idle, no problems.. if it's one of the SCHED_NORMAL
tasks (or imagine, some other use-cases in the future -- i.e. we should
not make outer world dependent on internal details of sched_fair class)
-- it may be "Houston, we've got a problem" case.

it's +16 bytes to the ".text". Another variant is to make 'run_node' the
first data member of 'struct sched_entity' but an additional check (se !
= NULL) is still needed in pick_next_entity().

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: vslice fixups for non-0 nice levels

Make vslice accurate wrt nice levels, and add some comments
while we're at it.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: whitespace cleanups

more whitespace cleanups. No code changed:

      text    data     bss     dec     hex filename
     26553    2790     288   29631    73bf sched.o.before
     26553    2790     288   29631    73bf sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: mark scheduling classes as const

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: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: group scheduler, fix latency

There is a possibility that because of task of a group moving from one
cpu to another, it may gain more cpu time that desired. See
http://marc.info/?l=linux-kernel&m=119073197730334 for details.

This is an attempt to fix that problem. Basically it simulates dequeue
of higher level entities as if they are going to sleep. Similarly it
simulate wakeup of higher level entities as if they are waking up from
sleep.

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: group scheduler, fix bloat

Recent fix to check_preempt_wakeup() to check for preemption at higher
levels caused a size bloat for !CONFIG_FAIR_GROUP_SCHED.

Fix the problem.

  42277   10598     320   53195    cfcb kernel/sched.o-before_this_patch
  42216   10598     320   53134    cf8e kernel/sched.o-after_this_patch

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: group scheduler, fix coding style issues

Fix coding style issues reported by Randy Dunlap and others

Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: cleanup, remove stale comment

cleanup, remove stale comment.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: speed up and simplify vslice calculations

speed up and simplify vslice calculations.

[ From: Mike Galbraith <efault@gmx.de>: build fix ]

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: clean up min_vruntime use

clean up min_vruntime use.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: group scheduler SMP migration fix

group scheduler SMP migration fix: use task_cfs_rq(p) to get
to the relevant fair-scheduling runqueue of a task, rq->cfs
is not the right one.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: clean up schedstats, cnt -> count

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: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: yield fix

fix yield bugs due to the current-not-in-rbtree changes: the task is
not in the rbtree so rbtree-removal is a no-no.

[ From: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>: build fix. ]

also, nice code size reduction:

kernel/sched.o:
   text    data     bss     dec     hex filename
  38323    3506      24   41853    a37d sched.o.before
  38236    3506      24   41766    a326 sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: group scheduler wakeup latency fix

group scheduler wakeup latency fix: when checking for preemption
we must check cross-group too, not just intra-group.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

sched: remove set_leftmost()

Lee Schermerhorn noticed that set_leftmost() contains dead code,
remove this.

Reported-by: Lee Schermerhorn <Lee.Schermerhorn@hp.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: clean up sched_fork()

The adjusting sched_class is a missing part of the already existing "do
not leak PI boosting priority to the child" at the sched_fork(). This
patch moves the adjusting sched_class from wake_up_new_task() to
sched_fork().

this also shrinks the code a bit:

   text    data     bss     dec     hex filename
  40111    4018     292   44421    ad85 sched.o.before
  40102    4018     292   44412    ad7c sched.o.after

Signed-off-by: Hiroshi Shimamoto <h-shimamoto@ct.jp.nec.com>
Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: max_vruntime() simplification

max_vruntime() simplification.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: fix sched_fork()

fix sched_fork(): large latencies at new task creation time because
the ->vruntime was not fixed up cross-CPU, if the parent got migrated
after the child's CPU got set up.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: fix sign check error in place_entity()

fix sign check error in place_entity() - we'd get excessive
latencies due to negatives being converted to large u64's.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: undo some of the recent changes

undo some of the recent changes that are not needed after all,
such as last_min_vruntime.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: remove last_min_vruntime effect

remove last_min_vruntime use - prepare to remove it.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: remove condition from set_task_cpu()

remove condition from set_task_cpu(). Now that ->vruntime
is not global anymore, it should (and does) work fine without
it too.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: entity_key() fix

entity_key() fix - we'd occasionally end up with a 0 vruntime
in the !initial case.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched debug: check spread

debug feature: check how well we schedule within a reasonable
vruntime 'spread' range. (note that CPU overload can increase
the spread, so this is not a hard condition, but normal loads
should be within the spread.)

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched debug: more width for parameter printouts

more width for parameter printouts in /proc/sched_debug.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: add vslice

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: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched debug: print settings

print the current value of all tunables in /proc/sched_debug output.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: remove unneeded tunables

remove unneeded tunables.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched debug: BKL usage statistics, fix

build fix for the SCHED_DEBUG && !SCHEDSTATS case.

Signed-off-by: S.Ceglar Onur <caglar@pardus.org.tr>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched debug: BKL usage statistics

add per task and per rq BKL usage statistics.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: enable CONFIG_FAIR_GROUP_SCHED=y by default

enable CONFIG_FAIR_GROUP_SCHED=y by default.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: fair-group sched, cleanups

fair-group sched, cleanups.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: add fair-user scheduler

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: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: clean up code under CONFIG_FAIR_GROUP_SCHED

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: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: print &rq->cfs stats

- Print &rq->cfs statistics as well (useful for group scheduling)

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: print nr_running and load in /proc/sched_debug

- print nr_running and load information for cfs_rq in /proc/sched_debug

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: fix minor bug in yield

- fix a minor bug in yield (seen for CONFIG_FAIR_GROUP_SCHED),
  group scheduling would skew when yield was called.

Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: revert recent removal of set_curr_task()

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: Dhaval Giani <dhaval@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>

sched: kernel/sched_fair.c whitespace cleanups

some trivial whitespace cleanups.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: fix formatting of /proc/sched_debug

fix formatting of /proc/sched_debug

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: enhance debug output

enhance debug output by changing 12345678 nsecs to 12.345678 output,
this is more human-readable.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: prettify /proc/sched_debug output

print the correct amount of dashes in /proc/sched_debug.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: rework enqueue/dequeue_entity() to get rid of set_curr_task()

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: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Srivatsa Vaddagiri <vatsa@linux.vnet.ibm.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: simplify sched_class::yield_task()

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: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: optimize task_new_fair()

due to the fact that we no longer keep the 'current' within the tree,
dequeue/enqueue_entity() is useless for the 'current' in
task_new_fair(). We are about to reschedule and
sched_class->put_prev_task() will put the 'current' back into the tree,
based on its new key.

   text    data     bss     dec     hex filename
  24388    2734      20   27142    6a06 sched.o.before
  24341    2734      20   27095    69d7 sched.o.after

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: fix delay accounting performance regression

fix delay accounting performance regression - those sched_clock()
calls are not needed.

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: do not keep current in the tree and get rid of sched_entity::fair_key

Get rid of 'sched_entity::fair_key'.

As a side effect, 'current' is not kept withing the tree for
SCHED_NORMAL/BATCH tasks anymore. This simplifies some parts of code
(e.g. entity_tick() and yield_task_fair()) and also somewhat optimizes
them (e.g. a single update_curr() now vs. dequeue/enqueue() before in
entity_tick()).

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: add set_curr_task() calls

p->sched_class->set_curr_task() has to be called before
activate_task()/enqueue_task() in rt_mutex_setprio(),
sched_setschedule() and sched_move_task() in order to set up
'cfs_rq->curr'. The logic of enqueueing depends on whether a task to be
inserted is 'current' or not.

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: sched_setscheduler() fix

Fix a problem in the 'sched-group' patch for !CONFIG_FAIR_GROUP_SCHED.

description:

sched_setscheduler()
{
...
if (task_running()) p->sched_class->put_prev_entity();

[ this one sets up cfs_rq->curr to NULL ]

...

if (task_running) p->sched_class->set_curr_task();

[ and this one is a _NOP_ (empty) for !CONFIG_FAIR_GROUP_SCHED ]

As a result, the task continues to run with cfs_rq->curr == NULL... no
crashes (due to checks for !NULL in place) but e.g. update_curr()
effectively becomes a NOP... i.e. runtime statistics for this task is
not accounted untill it's rescheduled anew.

Signed-off-by: Dmitry Adamushko <dmitry.adamushko@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: group-scheduler core

Add interface to control cpu bandwidth allocation to task-groups.

(not yet configurable, due to missing CONFIG_CONTAINERS)

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

sched: fix SMP migration latencies

fix SMP migration latencies: the vruntimes of different CPUs are
at incompatible offsets so they have to be fixed up when migrating
a task across CPUs.

Signed-off-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: better min_vruntime tracking

Better min_vruntime tracking: update it every time 'curr' is
updated - not just when a task is enqueued into the tree.

Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>

sched: x86: allow single-depth wchan output

sched.o gets smaller and faster if we compile it with -fomit-frame-pointers,
so make this a config option. The cost is the loss of multi-depth wchan
lookups - but SysRq-T is a sufficient replacement for them anyway, so their
utility is much lower these days.

the size difference is significant:

   text    data     bss     dec     hex filename
  34005    3462      24   37491    9273 sched.o.before
  33470    3462      24   36956    905c sched.o.after

Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Signed-off-by: Mike Galbraith <efault@gmx.de>
Reviewed-by: Thomas Gleixner <tglx@linutronix.de>