linux-toradex.git/kernel/sched_rt.c, branch v3.0-rc3

sched: More sched_domain iterations fixes

2011-05-28T15:02:54+00:00

sched_domain iterations needs to be protected by rcu_read_lock() now,
this patch adds another two places which needs the rcu lock, which is
spotted by following suspicious rcu_dereference_check() usage warnings.

kernel/sched_rt.c:1244 invoked rcu_dereference_check() without protection!
kernel/sched_stats.h:41 invoked rcu_dereference_check() without protection!

Signed-off-by: Xiaotian Feng 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1303469634-11678-1-git-send-email-dfeng@redhat.com
Signed-off-by: Ingo Molnar

Merge branches 'sched-core-for-linus' and 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip

2011-05-20T00:41:22+00:00

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip: (60 commits)
  sched: Fix and optimise calculation of the weight-inverse
  sched: Avoid going ahead if ->cpus_allowed is not changed
  sched, rt: Update rq clock when unthrottling of an otherwise idle CPU
  sched: Remove unused parameters from sched_fork() and wake_up_new_task()
  sched: Shorten the construction of the span cpu mask of sched domain
  sched: Wrap the 'cfs_rq->nr_spread_over' field with CONFIG_SCHED_DEBUG
  sched: Remove unused 'this_best_prio arg' from balance_tasks()
  sched: Remove noop in alloc_rt_sched_group()
  sched: Get rid of lock_depth
  sched: Remove obsolete comment from scheduler_tick()
  sched: Fix sched_domain iterations vs. RCU
  sched: Next buddy hint on sleep and preempt path
  sched: Make set_*_buddy() work on non-task entities
  sched: Remove need_migrate_task()
  sched: Move the second half of ttwu() to the remote cpu
  sched: Restructure ttwu() some more
  sched: Rename ttwu_post_activation() to ttwu_do_wakeup()
  sched: Remove rq argument from ttwu_stat()
  sched: Remove rq->lock from the first half of ttwu()
  sched: Drop rq->lock from sched_exec()
  ...

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/linux-2.6-tip:
  sched: Fix rt_rq runtime leakage bug

sched, rt: Update rq clock when unthrottling of an otherwise idle CPU

2011-05-16T09:01:17+00:00

If an RT task is awakened while it's rt_rq is throttled, the time between
wakeup/enqueue and unthrottle/selection may be accounted as rt_time
if the CPU is idle.  Set rq->skip_clock_update negative upon throttle
release to tell put_prev_task() that we need a clock update.

Reported-by: Thomas Giesel 
Signed-off-by: Mike Galbraith 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/1304059010.7472.1.camel@marge.simson.net
Signed-off-by: Ingo Molnar

sched: Fix rt_rq runtime leakage bug

2011-05-16T09:00:54+00:00

This patch is to fix the real-time scheduler bug reported at:

  https://lkml.org/lkml/2011/4/26/13

That is, when running multiple real-time threads on every logical CPUs
and then turning off one CPU, the kernel will bug at function
__disable_runtime().

Function __disable_runtime() bugs and reports leakage of rt_rq runtime.
The root cause is __disable_runtime() assumes it iterates through all
the existing rt_rq's while walking rq->leaf_rt_rq_list, which actually
contains only runnable rt_rq's. This problem also applies to
__enable_runtime() and print_rt_stats().

The patch is based on above analysis, appears to fix the problem, but is
only lightly tested.

Reported-by: Paul E. McKenney 
Tested-by: Paul E. McKenney 
Signed-off-by: Cheng Xu 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/4DCE1F12.6040609@linux.vnet.ibm.com
Signed-off-by: Ingo Molnar

sched: Drop the rq argument to sched_class::select_task_rq()

2011-04-14T06:52:36+00:00

In preparation of calling select_task_rq() without rq->lock held, drop
the dependency on the rq argument.

Reviewed-by: Frank Rowand 
Signed-off-by: Peter Zijlstra 
Cc: Mike Galbraith 
Cc: Nick Piggin 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Link: http://lkml.kernel.org/r/20110405152729.031077745@chello.nl
Signed-off-by: Ingo Molnar

sched: Provide p->on_rq

2011-04-14T06:52:35+00:00

Provide a generic p->on_rq because the p->se.on_rq semantics are
unfavourable for lockless wakeups but needed for sched_fair.

In particular, p->on_rq is only cleared when we actually dequeue the
task in schedule() and not on any random dequeue as done by things
like __migrate_task() and __sched_setscheduler().

This also allows us to remove p->se usage from !sched_fair code.

Reviewed-by: Frank Rowand 
Cc: Mike Galbraith 
Cc: Nick Piggin 
Cc: Linus Torvalds 
Cc: Andrew Morton 
Signed-off-by: Ingo Molnar 
Signed-off-by: Peter Zijlstra 
Link: http://lkml.kernel.org/r/20110405152728.949545047@chello.nl

Fix common misspellings

2011-03-31T14:26:23+00:00

Fixes generated by 'codespell' and manually reviewed.

Signed-off-by: Lucas De Marchi

Merge branch 'sched/urgent' into sched/core

2011-03-04T10:12:26+00:00

Merge reason: Add fixes before applying dependent patches.

Signed-off-by: Ingo Molnar

sched: Fix sched rt group scheduling when hierachy is enabled

2011-03-04T10:03:18+00:00

The current sched rt code is broken when it comes to hierarchical
scheduling, this patch fixes two problems

1. It adds redundant enqueuing (harmless) when it finds a queue
   has tasks enqueued, but it has no run time and it is not
   throttled.

2. The most important change is in sched_rt_rq_enqueue/dequeue.
   The code just picks the rt_rq belonging to the current cpu
   on which the period timer runs, the patch fixes it, so that
   the correct rt_se is enqueued/dequeued.

Tested with a simple hierarchy

/c/d, c and d assigned similar runtimes of 50,000 and a while
1 loop runs within "d". Both c and d get throttled, without
the patch, the task just stops running and never runs (depends
on where the sched_rt b/w timer runs). With the patch, the
task is throttled and runs as expected.

[ bharata, suggestions on how to pick the rt_se belong to the
  rt_rq and correct cpu ]

Signed-off-by: Balbir Singh 
Acked-by: Bharata B Rao 
Signed-off-by: Peter Zijlstra 
Cc: stable@kernel.org
LKML-Reference: <20110303113435.GA2868@balbir.in.ibm.com>
Signed-off-by: Ingo Molnar

Merge commit 'v2.6.38-rc5' into sched/core

2011-02-16T12:31:55+00:00

Merge reason: Pick up upstream fixes.

Signed-off-by: Ingo Molnar