From 0121805d9d2b1fff371e195c28e9b86ae38b5e47 Mon Sep 17 00:00:00 2001 From: Matthias Kaehlcke Date: Mon, 28 Jan 2019 15:46:24 -0800 Subject: kthread: Add __kthread_should_park() kthread_should_park() is used to check if the calling kthread ('current') should park, but there is no function to check whether an arbitrary kthread should be parked. The latter is required to plug a CPU hotplug race vs. a parking ksoftirqd thread. The new __kthread_should_park() receives a task_struct as parameter to check if the corresponding kernel thread should be parked. Call __kthread_should_park() from kthread_should_park() to avoid code duplication. Signed-off-by: Matthias Kaehlcke Signed-off-by: Thomas Gleixner Cc: Peter Zijlstra Cc: Steven Rostedt Cc: "Paul E . McKenney" Cc: Sebastian Andrzej Siewior Cc: Douglas Anderson Cc: Stephen Boyd Link: https://lkml.kernel.org/r/20190128234625.78241-2-mka@chromium.org --- include/linux/kthread.h | 1 + 1 file changed, 1 insertion(+) (limited to 'include/linux/kthread.h') diff --git a/include/linux/kthread.h b/include/linux/kthread.h index c1961761311d..1577a2d56e9d 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -56,6 +56,7 @@ void kthread_bind_mask(struct task_struct *k, const struct cpumask *mask); int kthread_stop(struct task_struct *k); bool kthread_should_stop(void); bool kthread_should_park(void); +bool __kthread_should_park(struct task_struct *k); bool kthread_freezable_should_stop(bool *was_frozen); void *kthread_data(struct task_struct *k); void *kthread_probe_data(struct task_struct *k); -- cgit v1.2.3-71-gd317 From fe99a4f4d6022ec92f9b52a5528cb9b77513e7d1 Mon Sep 17 00:00:00 2001 From: Julia Cartwright Date: Tue, 12 Feb 2019 17:25:53 +0100 Subject: kthread: Convert worker lock to raw spinlock In order to enable the queuing of kthread work items from hardirq context even when PREEMPT_RT_FULL is enabled, convert the worker spin_lock to a raw_spin_lock. This is only acceptable to do because the work performed under the lock is well-bounded and minimal. Reported-by: Steffen Trumtrar Reported-by: Tim Sander Signed-off-by: Julia Cartwright Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Tested-by: Steffen Trumtrar Reviewed-by: Petr Mladek Cc: Guenter Roeck Link: https://lkml.kernel.org/r/20190212162554.19779-1-bigeasy@linutronix.de --- include/linux/kthread.h | 4 ++-- kernel/kthread.c | 42 +++++++++++++++++++++--------------------- 2 files changed, 23 insertions(+), 23 deletions(-) (limited to 'include/linux/kthread.h') diff --git a/include/linux/kthread.h b/include/linux/kthread.h index c1961761311d..6b8c064f0cbc 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -85,7 +85,7 @@ enum { struct kthread_worker { unsigned int flags; - spinlock_t lock; + raw_spinlock_t lock; struct list_head work_list; struct list_head delayed_work_list; struct task_struct *task; @@ -106,7 +106,7 @@ struct kthread_delayed_work { }; #define KTHREAD_WORKER_INIT(worker) { \ - .lock = __SPIN_LOCK_UNLOCKED((worker).lock), \ + .lock = __RAW_SPIN_LOCK_UNLOCKED((worker).lock), \ .work_list = LIST_HEAD_INIT((worker).work_list), \ .delayed_work_list = LIST_HEAD_INIT((worker).delayed_work_list),\ } diff --git a/kernel/kthread.c b/kernel/kthread.c index 087d18d771b5..5641b55783a6 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -599,7 +599,7 @@ void __kthread_init_worker(struct kthread_worker *worker, struct lock_class_key *key) { memset(worker, 0, sizeof(struct kthread_worker)); - spin_lock_init(&worker->lock); + raw_spin_lock_init(&worker->lock); lockdep_set_class_and_name(&worker->lock, key, name); INIT_LIST_HEAD(&worker->work_list); INIT_LIST_HEAD(&worker->delayed_work_list); @@ -641,21 +641,21 @@ repeat: if (kthread_should_stop()) { __set_current_state(TASK_RUNNING); - spin_lock_irq(&worker->lock); + raw_spin_lock_irq(&worker->lock); worker->task = NULL; - spin_unlock_irq(&worker->lock); + raw_spin_unlock_irq(&worker->lock); return 0; } work = NULL; - spin_lock_irq(&worker->lock); + raw_spin_lock_irq(&worker->lock); if (!list_empty(&worker->work_list)) { work = list_first_entry(&worker->work_list, struct kthread_work, node); list_del_init(&work->node); } worker->current_work = work; - spin_unlock_irq(&worker->lock); + raw_spin_unlock_irq(&worker->lock); if (work) { __set_current_state(TASK_RUNNING); @@ -812,12 +812,12 @@ bool kthread_queue_work(struct kthread_worker *worker, bool ret = false; unsigned long flags; - spin_lock_irqsave(&worker->lock, flags); + raw_spin_lock_irqsave(&worker->lock, flags); if (!queuing_blocked(worker, work)) { kthread_insert_work(worker, work, &worker->work_list); ret = true; } - spin_unlock_irqrestore(&worker->lock, flags); + raw_spin_unlock_irqrestore(&worker->lock, flags); return ret; } EXPORT_SYMBOL_GPL(kthread_queue_work); @@ -843,7 +843,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t) if (WARN_ON_ONCE(!worker)) return; - spin_lock(&worker->lock); + raw_spin_lock(&worker->lock); /* Work must not be used with >1 worker, see kthread_queue_work(). */ WARN_ON_ONCE(work->worker != worker); @@ -852,7 +852,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t) list_del_init(&work->node); kthread_insert_work(worker, work, &worker->work_list); - spin_unlock(&worker->lock); + raw_spin_unlock(&worker->lock); } EXPORT_SYMBOL(kthread_delayed_work_timer_fn); @@ -908,14 +908,14 @@ bool kthread_queue_delayed_work(struct kthread_worker *worker, unsigned long flags; bool ret = false; - spin_lock_irqsave(&worker->lock, flags); + raw_spin_lock_irqsave(&worker->lock, flags); if (!queuing_blocked(worker, work)) { __kthread_queue_delayed_work(worker, dwork, delay); ret = true; } - spin_unlock_irqrestore(&worker->lock, flags); + raw_spin_unlock_irqrestore(&worker->lock, flags); return ret; } EXPORT_SYMBOL_GPL(kthread_queue_delayed_work); @@ -951,7 +951,7 @@ void kthread_flush_work(struct kthread_work *work) if (!worker) return; - spin_lock_irq(&worker->lock); + raw_spin_lock_irq(&worker->lock); /* Work must not be used with >1 worker, see kthread_queue_work(). */ WARN_ON_ONCE(work->worker != worker); @@ -963,7 +963,7 @@ void kthread_flush_work(struct kthread_work *work) else noop = true; - spin_unlock_irq(&worker->lock); + raw_spin_unlock_irq(&worker->lock); if (!noop) wait_for_completion(&fwork.done); @@ -996,9 +996,9 @@ static bool __kthread_cancel_work(struct kthread_work *work, bool is_dwork, * any queuing is blocked by setting the canceling counter. */ work->canceling++; - spin_unlock_irqrestore(&worker->lock, *flags); + raw_spin_unlock_irqrestore(&worker->lock, *flags); del_timer_sync(&dwork->timer); - spin_lock_irqsave(&worker->lock, *flags); + raw_spin_lock_irqsave(&worker->lock, *flags); work->canceling--; } @@ -1045,7 +1045,7 @@ bool kthread_mod_delayed_work(struct kthread_worker *worker, unsigned long flags; int ret = false; - spin_lock_irqsave(&worker->lock, flags); + raw_spin_lock_irqsave(&worker->lock, flags); /* Do not bother with canceling when never queued. */ if (!work->worker) @@ -1062,7 +1062,7 @@ bool kthread_mod_delayed_work(struct kthread_worker *worker, fast_queue: __kthread_queue_delayed_work(worker, dwork, delay); out: - spin_unlock_irqrestore(&worker->lock, flags); + raw_spin_unlock_irqrestore(&worker->lock, flags); return ret; } EXPORT_SYMBOL_GPL(kthread_mod_delayed_work); @@ -1076,7 +1076,7 @@ static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork) if (!worker) goto out; - spin_lock_irqsave(&worker->lock, flags); + raw_spin_lock_irqsave(&worker->lock, flags); /* Work must not be used with >1 worker, see kthread_queue_work(). */ WARN_ON_ONCE(work->worker != worker); @@ -1090,13 +1090,13 @@ static bool __kthread_cancel_work_sync(struct kthread_work *work, bool is_dwork) * In the meantime, block any queuing by setting the canceling counter. */ work->canceling++; - spin_unlock_irqrestore(&worker->lock, flags); + raw_spin_unlock_irqrestore(&worker->lock, flags); kthread_flush_work(work); - spin_lock_irqsave(&worker->lock, flags); + raw_spin_lock_irqsave(&worker->lock, flags); work->canceling--; out_fast: - spin_unlock_irqrestore(&worker->lock, flags); + raw_spin_unlock_irqrestore(&worker->lock, flags); out: return ret; } -- cgit v1.2.3-71-gd317 From ad01423aedaa7c6dd62d560b73a3cb39e6da3901 Mon Sep 17 00:00:00 2001 From: Sebastian Andrzej Siewior Date: Tue, 12 Feb 2019 17:25:54 +0100 Subject: kthread: Do not use TIMER_IRQSAFE The TIMER_IRQSAFE usage was introduced in commit 22597dc3d97b1 ("kthread: initial support for delayed kthread work") which modelled the delayed kthread code after workqueue's code. The workqueue code requires the flag TIMER_IRQSAFE for synchronisation purpose. This is not true for kthread's delay timer since all operations occur under a lock. Remove TIMER_IRQSAFE from the timer initialisation and use timer_setup() for initialisation purpose which is the official function. Signed-off-by: Sebastian Andrzej Siewior Signed-off-by: Thomas Gleixner Reviewed-by: Petr Mladek Link: https://lkml.kernel.org/r/20190212162554.19779-2-bigeasy@linutronix.de --- include/linux/kthread.h | 5 ++--- kernel/kthread.c | 5 +++-- 2 files changed, 5 insertions(+), 5 deletions(-) (limited to 'include/linux/kthread.h') diff --git a/include/linux/kthread.h b/include/linux/kthread.h index 6b8c064f0cbc..3d9d834c66a2 100644 --- a/include/linux/kthread.h +++ b/include/linux/kthread.h @@ -164,9 +164,8 @@ extern void __kthread_init_worker(struct kthread_worker *worker, #define kthread_init_delayed_work(dwork, fn) \ do { \ kthread_init_work(&(dwork)->work, (fn)); \ - __init_timer(&(dwork)->timer, \ - kthread_delayed_work_timer_fn, \ - TIMER_IRQSAFE); \ + timer_setup(&(dwork)->timer, \ + kthread_delayed_work_timer_fn, 0); \ } while (0) int kthread_worker_fn(void *worker_ptr); diff --git a/kernel/kthread.c b/kernel/kthread.c index 5641b55783a6..537335541267 100644 --- a/kernel/kthread.c +++ b/kernel/kthread.c @@ -835,6 +835,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t) struct kthread_delayed_work *dwork = from_timer(dwork, t, timer); struct kthread_work *work = &dwork->work; struct kthread_worker *worker = work->worker; + unsigned long flags; /* * This might happen when a pending work is reinitialized. @@ -843,7 +844,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t) if (WARN_ON_ONCE(!worker)) return; - raw_spin_lock(&worker->lock); + raw_spin_lock_irqsave(&worker->lock, flags); /* Work must not be used with >1 worker, see kthread_queue_work(). */ WARN_ON_ONCE(work->worker != worker); @@ -852,7 +853,7 @@ void kthread_delayed_work_timer_fn(struct timer_list *t) list_del_init(&work->node); kthread_insert_work(worker, work, &worker->work_list); - raw_spin_unlock(&worker->lock); + raw_spin_unlock_irqrestore(&worker->lock, flags); } EXPORT_SYMBOL(kthread_delayed_work_timer_fn); -- cgit v1.2.3-71-gd317