linux/kernel/cpu.c, branch v4.5

kernel/cpu.c: make set_cpu_* static inlines

2016-01-21T01:09:18Z

Almost all callers of the set_cpu_* functions pass an explicit true or false. Making them static inline thus replaces the function calls with a simple set_bit/clear_bit, saving some .text. Signed-off-by: Rasmus Villemoes Acked-by: Rusty Russell Cc: Greg Kroah-Hartman Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/cpu.c: eliminate cpu_*_mask

2016-01-21T01:09:18Z

Replace the variables cpu_possible_mask, cpu_online_mask, cpu_present_mask and cpu_active_mask with macros expanding to expressions of the same type and value, eliminating some indirection. Signed-off-by: Rasmus Villemoes Acked-by: Rusty Russell Cc: Greg Kroah-Hartman Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/cpu.c: export __cpu_*_mask

2016-01-21T01:09:18Z

Exporting the cpumasks __cpu_possible_mask and friends will allow us to remove the extra indirection through the cpu_*_mask variables. It will also allow the set_cpu_* functions to become static inlines, which will give a .text reduction. Signed-off-by: Rasmus Villemoes Acked-by: Rusty Russell Cc: Greg Kroah-Hartman Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

kernel/cpu.c: change type of cpu_possible_bits and friends

2016-01-21T01:09:18Z

Change cpu_possible_bits and friends (online, present, active) from being bitmaps that happen to have the right size to actually being struct cpumasks. Also rename them to __cpu_xyz_mask. This is mostly a small cleanup in preparation for exporting them and, eventually, eliminating the extra indirection through the cpu_xyz_mask variables. Signed-off-by: Rasmus Villemoes Acked-by: Rusty Russell Cc: Greg Kroah-Hartman Cc: Michael Ellerman Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds

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

2015-11-04T02:03:50Z

Pull scheduler changes from Ingo Molnar: "The main changes in this cycle were: - sched/fair load tracking fixes and cleanups (Byungchul Park) - Make load tracking frequency scale invariant (Dietmar Eggemann) - sched/deadline updates (Juri Lelli) - stop machine fixes, cleanups and enhancements for bugs triggered by CPU hotplug stress testing (Oleg Nesterov) - scheduler preemption code rework: remove PREEMPT_ACTIVE and related cleanups (Peter Zijlstra) - Rework the sched_info::run_delay code to fix races (Peter Zijlstra) - Optimize per entity utilization tracking (Peter Zijlstra) - ... misc other fixes, cleanups and smaller updates" * 'sched-core-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: (57 commits) sched: Don't scan all-offline ->cpus_allowed twice if !CONFIG_CPUSETS sched: Move cpu_active() tests from stop_two_cpus() into migrate_swap_stop() sched: Start stopper early stop_machine: Kill cpu_stop_threads->setup() and cpu_stop_unpark() stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark() stop_machine: Change cpu_stop_queue_two_works() to rely on stopper->enabled stop_machine: Introduce __cpu_stop_queue_work() and cpu_stop_queue_two_works() stop_machine: Ensure that a queued callback will be called before cpu_stop_park() sched/x86: Fix typo in __switch_to() comments sched/core: Remove a parameter in the migrate_task_rq() function sched/core: Drop unlikely behind BUG_ON() sched/core: Fix task and run queue sched_info::run_delay inconsistencies sched/numa: Fix task_tick_fair() from disabling numa_balancing sched/core: Add preempt_count invariant check sched/core: More notrace annotations sched/core: Kill PREEMPT_ACTIVE sched/core, sched/x86: Kill thread_info::saved_preempt_count sched/core: Simplify preempt_count tests sched/core: Robustify preemption leak checks sched/core: Stop setting PREEMPT_ACTIVE ...

sched: Start stopper early

2015-10-20T08:25:55Z

Ensure the stopper thread is active 'early', because the load balancer pretty much assumes that its available. And when 'online && active' the load-balancer is fully available. Not only the numa balancing stop_two_cpus() caller relies on it, but also the self migration stuff does, and at CPU_ONLINE time the cpu really is 'free' to run anything. Signed-off-by: Peter Zijlstra (Intel) Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Tejun Heo Cc: Thomas Gleixner Cc: heiko.carstens@de.ibm.com Link: http://lkml.kernel.org/r/20151009160054.GA10176@redhat.com Signed-off-by: Ingo Molnar

stop_machine: Kill smp_hotplug_thread->pre_unpark, introduce stop_machine_unpark()

2015-10-20T08:23:55Z

1. Change smpboot_unpark_thread() to check ->selfparking, just like smpboot_park_thread() does. 2. Introduce stop_machine_unpark() which sets ->enabled and calls kthread_unpark(). 3. Change smpboot_thread_call() and cpu_stop_init() to call stop_machine_unpark() by hand. This way: - IMO the ->selfparking logic becomes more consistent. - We can kill the smp_hotplug_thread->pre_unpark() method. - We can easily unpark the stopper thread earlier. Say, we can move stop_machine_unpark() from smpboot_thread_call() to sched_cpu_active() as Peter suggests. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Tejun Heo Cc: Thomas Gleixner Cc: heiko.carstens@de.ibm.com Link: http://lkml.kernel.org/r/20151009160049.GA10166@redhat.com Signed-off-by: Ingo Molnar

stop_machine: Ensure that a queued callback will be called before cpu_stop_park()

2015-10-20T08:23:53Z

cpu_stop_queue_work() checks stopper->enabled before it queues the work, but ->enabled == T can only guarantee cpu_stop_signal_done() if we race with cpu_down(). This is not enough for stop_two_cpus() or stop_machine(), they will deadlock if multi_cpu_stop() won't be called by one of the target CPU's. stop_machine/stop_cpus are fine, they rely on stop_cpus_mutex. But stop_two_cpus() has to check cpu_active() to avoid the same race with hotplug, and this check is very unobvious and probably not even correct if we race with cpu_up(). Change cpu_down() pass to clear ->enabled before cpu_stopper_thread() flushes the pending ->works and returns with KTHREAD_SHOULD_PARK set. Note also that smpboot_thread_call() calls cpu_stop_unpark() which sets enabled == T at CPU_ONLINE stage, so this CPU can't go away until cpu_stopper_thread() is called at least once. This all means that if cpu_stop_queue_work() succeeds, we know that work->fn() will be called. Signed-off-by: Oleg Nesterov Signed-off-by: Peter Zijlstra (Intel) Cc: Andrew Morton Cc: Linus Torvalds Cc: Mike Galbraith Cc: Paul E. McKenney Cc: Peter Zijlstra Cc: Rik van Riel Cc: Tejun Heo Cc: Thomas Gleixner Cc: heiko.carstens@de.ibm.com Link: http://lkml.kernel.org/r/20151008145131.GA18139@redhat.com Signed-off-by: Ingo Molnar

cpu: Remove try_get_online_cpus()

2015-10-07T23:02:49Z

Now that synchronize_sched_expedited() no longer uses it, there are no users of try_get_online_cpus() in mainline. This commit therefore removes it. Signed-off-by: Paul E. McKenney Cc: Peter Zijlstra Cc: Thomas Gleixner

cpu/hotplug: Read_lock(tasklist_lock) doesn't need to disable irqs

2015-09-12T09:54:27Z

check_for_tasks() doesn't need to disable irqs, recursive read_lock() from interrupt is fine. While at it, s/do_each_thread/for_each_process_thread/. Signed-off-by: Oleg Nesterov Reviewed-by: Kirill Tkhai Reviewed-by: Srikar Dronamraju Cc: Kirill Tkhai Cc: Linus Torvalds Cc: Peter Zijlstra Cc: Thomas Gleixner Link: http://lkml.kernel.org/r/20150910130750.GA20055@redhat.com Signed-off-by: Ingo Molnar