linux.git/kernel/sched/core.c, branch v3.18-rc2

Merge branch 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-10-13T14:23:15+00:00

Pull scheduler updates from Ingo Molnar:
 "The main changes in this cycle were:

   - Optimized support for Intel "Cluster-on-Die" (CoD) topologies (Dave
     Hansen)

   - Various sched/idle refinements for better idle handling (Nicolas
     Pitre, Daniel Lezcano, Chuansheng Liu, Vincent Guittot)

   - sched/numa updates and optimizations (Rik van Riel)

   - sysbench speedup (Vincent Guittot)

   - capacity calculation cleanups/refactoring (Vincent Guittot)

   - Various cleanups to thread group iteration (Oleg Nesterov)

   - Double-rq-lock removal optimization and various refactorings
     (Kirill Tkhai)

   - various sched/deadline fixes

  ... and lots of other changes"

* 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (72 commits)
  sched/dl: Use dl_bw_of() under rcu_read_lock_sched()
  sched/fair: Delete resched_cpu() from idle_balance()
  sched, time: Fix build error with 64 bit cputime_t on 32 bit systems
  sched: Improve sysbench performance by fixing spurious active migration
  sched/x86: Fix up typo in topology detection
  x86, sched: Add new topology for multi-NUMA-node CPUs
  sched/rt: Use resched_curr() in task_tick_rt()
  sched: Use rq->rd in sched_setaffinity() under RCU read lock
  sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'
  sched: Use dl_bw_of() under RCU read lock
  sched/fair: Remove duplicate code from can_migrate_task()
  sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW
  sched: print_rq(): Don't use tasklist_lock
  sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()
  sched: Fix the task-group check in tg_has_rt_tasks()
  sched/fair: Leverage the idle state info when choosing the "idlest" cpu
  sched: Let the scheduler see CPU idle states
  sched/deadline: Fix inter- exclusive cpusets migrations
  sched/deadline: Clear dl_entity params when setscheduling to different class
  sched/numa: Kill the wrong/dead TASK_DEAD check in task_numa_fault()
  ...

Merge branch 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2014-10-13T13:51:40+00:00

Pull core locking updates from Ingo Molnar:
 "The main updates in this cycle were:

   - mutex MCS refactoring finishing touches: improve comments, refactor
     and clean up code, reduce debug data structure footprint, etc.

   - qrwlock finishing touches: remove old code, self-test updates.

   - small rwsem optimization

   - various smaller fixes/cleanups"

* 'locking-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  locking/lockdep: Revert qrwlock recusive stuff
  locking/rwsem: Avoid double checking before try acquiring write lock
  locking/rwsem: Move EXPORT_SYMBOL() lines to follow function definition
  locking/rwlock, x86: Delete unused asm/rwlock.h and rwlock.S
  locking/rwlock, x86: Clean up asm/spinlock*.h to remove old rwlock code
  locking/semaphore: Resolve some shadow warnings
  locking/selftest: Support queued rwlock
  locking/lockdep: Restrict the use of recursive read_lock() with qrwlock
  locking/spinlocks: Always evaluate the second argument of spin_lock_nested()
  locking/Documentation: Update locking/mutex-design.txt disadvantages
  locking/Documentation: Move locking related docs into Documentation/locking/
  locking/mutexes: Use MUTEX_SPIN_ON_OWNER when appropriate
  locking/mutexes: Refactor optimistic spinning code
  locking/mcs: Remove obsolete comment
  locking/mutexes: Document quick lock release when unlocking
  locking/mutexes: Standardize arguments in lock/unlock slowpaths
  locking: Remove deprecated smp_mb__() barriers

sched/dl: Use dl_bw_of() under rcu_read_lock_sched()

2014-10-03T03:46:58+00:00

rq->rd is freed using call_rcu_sched(), so rcu_read_lock() to access it
is not enough. We should use either rcu_read_lock_sched() or preempt_disable().

Reported-by: Sasha Levin 
Suggested-by: Peter Zijlstra 
Signed-off-by: Kirill Tkhai 
Fixes: 66339c31bc39 "sched: Use dl_bw_of() under RCU read lock"
Link: http://lkml.kernel.org/r/1412065417.20287.24.camel@tkhai
Signed-off-by: Ingo Molnar

sched: Use rq->rd in sched_setaffinity() under RCU read lock

2014-09-24T12:47:11+00:00

Probability of use-after-free isn't zero in this place.

Signed-off-by: Kirill Tkhai 
Signed-off-by: Peter Zijlstra (Intel) 
Cc:  # v3.14+
Cc: Paul E. McKenney 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20140922183636.11015.83611.stgit@localhost
Signed-off-by: Ingo Molnar

sched: cleanup: Rename 'out_unlock' to 'out_free_new_mask'

2014-09-24T12:47:10+00:00

Nothing is locked there, so label's name only confuses a reader.

Signed-off-by: Kirill Tkhai 
Signed-off-by: Peter Zijlstra (Intel) 
Link: http://lkml.kernel.org/r/20140922183630.11015.59500.stgit@localhost
Signed-off-by: Ingo Molnar

sched: Use dl_bw_of() under RCU read lock

2014-09-24T12:47:09+00:00

dl_bw_of() dereferences rq->rd which has to have RCU read lock held.
Probability of use-after-free isn't zero here.

Also add lockdep assert into dl_bw_cpus().

Signed-off-by: Kirill Tkhai 
Signed-off-by: Peter Zijlstra (Intel) 
Cc:  # v3.14+
Cc: Paul E. McKenney 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20140922183624.11015.71558.stgit@localhost
Signed-off-by: Ingo Molnar

sched, mips, ia64: Remove __ARCH_WANT_UNLOCKED_CTXSW

2014-09-24T12:47:05+00:00

Kirill found that there's a subtle race in the
__ARCH_WANT_UNLOCKED_CTXSW code, and instead of fixing it, remove the
entire exception because neither arch that uses it seems to actually
still require it.

Boot tested on mips64el (qemu) only.

Signed-off-by: Peter Zijlstra (Intel) 
Reviewed-by: Kirill Tkhai 
Cc: Andrew Morton 
Cc: Davidlohr Bueso 
Cc: Fenghua Yu 
Cc: James Hogan 
Cc: Kees Cook 
Cc: Linus Torvalds 
Cc: Paul Burton 
Cc: Qais Yousef 
Cc: Ralf Baechle 
Cc: Tony Luck 
Cc: oleg@redhat.com
Cc: linux@roeck-us.net
Cc: linux-ia64@vger.kernel.org
Cc: linux-kernel@vger.kernel.org
Cc: linux-mips@linux-mips.org
Link: http://lkml.kernel.org/r/20140923150641.GH3312@worktop.programming.kicks-ass.net
Signed-off-by: Ingo Molnar

sched: normalize_rt_tasks(): Don't use _irqsave for tasklist_lock, use task_rq_lock()

2014-09-24T12:47:03+00:00

1. read_lock(tasklist_lock) does not need to disable irqs.

2. ->mm != NULL is a common mistake, use PF_KTHREAD.

3. The second ->mm check can be simply removed.

4. task_rq_lock() looks better than raw_spin_lock(&p->pi_lock) +
   __task_rq_lock().

Signed-off-by: Oleg Nesterov 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Kirill Tkhai 
Cc: Mike Galbraith 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/20140921193338.GA28621@redhat.com
Signed-off-by: Ingo Molnar

sched: Fix the task-group check in tg_has_rt_tasks()

2014-09-24T12:47:00+00:00

tg_has_rt_tasks() wants to find an RT task in this task_group, but
task_rq(p)->rt.tg wrongly checks the root rt_rq.

Signed-off-by: Oleg Nesterov 
Reviewed-by: Kirill Tkhai 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Mike Galbraith 
Link: http://lkml.kernel.org/r/20140921193336.GA28618@redhat.com
Signed-off-by: Ingo Molnar

sched/deadline: Clear dl_entity params when setscheduling to different class

2014-09-24T12:46:56+00:00

When a task is using SCHED_DEADLINE and the user setschedules it to a
different class its sched_dl_entity static parameters are not cleaned
up. This causes a bug if the user sets it back to SCHED_DEADLINE with
the same parameters again.  The problem resides in the check we
perform at the very beginning of dl_overflow():

	if (new_bw == p->dl.dl_bw)
		return 0;

This condition is met in the case depicted above, so the function
returns and dl_b->total_bw is not updated (the p->dl.dl_bw is not
added to it). After this, admission control is broken.

This patch fixes the thing, properly clearing static parameters for a
task that ceases to use SCHED_DEADLINE.

Reported-by: Daniele Alessandrelli 
Reported-by: Daniel Wagner 
Reported-by: Vincent Legout 
Tested-by: Luca Abeni 
Tested-by: Daniel Wagner 
Tested-by: Vincent Legout 
Signed-off-by: Juri Lelli 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Fabio Checconi 
Cc: Dario Faggioli 
Cc: Michael Trimarchi 
Cc: Linus Torvalds 
Link: http://lkml.kernel.org/r/1411118561-26323-2-git-send-email-juri.lelli@arm.com
Signed-off-by: Ingo Molnar