diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2021-10-06 13:18:50 +0200 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2021-10-15 11:25:17 +0200 |
| commit | 810979682ccc98dbd83f341c18a2e556c30a7164 (patch) | |
| tree | a9d692207ee2df66d8292a5fe89ef0440465d419 /kernel | |
| parent | sched/rt: Annotate the RT balancing logic irqwork as IRQ_WORK_HARD_IRQ (diff) | |
| download | linux-810979682ccc98dbd83f341c18a2e556c30a7164.tar.xz linux-810979682ccc98dbd83f341c18a2e556c30a7164.zip | |
irq_work: Allow irq_work_sync() to sleep if irq_work() no IRQ support.
irq_work() triggers instantly an interrupt if supported by the
architecture. Otherwise the work will be processed on the next timer
tick. In worst case irq_work_sync() could spin up to a jiffy.
irq_work_sync() is usually used in tear down context which is fully
preemptible. Based on review irq_work_sync() is invoked from preemptible
context and there is one waiter at a time. This qualifies it to use
rcuwait for synchronisation.
Let irq_work_sync() synchronize with rcuwait if the architecture
processes irqwork via the timer tick.
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Link: https://lkml.kernel.org/r/20211006111852.1514359-3-bigeasy@linutronix.de
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq_work.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c index db8c248ebc8c..e789beda8297 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -160,6 +160,9 @@ void irq_work_single(void *arg) * else claimed it meanwhile. */ (void)atomic_cmpxchg(&work->node.a_flags, flags, flags & ~IRQ_WORK_BUSY); + + if (!arch_irq_work_has_interrupt()) + rcuwait_wake_up(&work->irqwait); } static void irq_work_run_list(struct llist_head *list) @@ -204,6 +207,13 @@ void irq_work_tick(void) void irq_work_sync(struct irq_work *work) { lockdep_assert_irqs_enabled(); + might_sleep(); + + if (!arch_irq_work_has_interrupt()) { + rcuwait_wait_event(&work->irqwait, !irq_work_is_busy(work), + TASK_UNINTERRUPTIBLE); + return; + } while (irq_work_is_busy(work)) cpu_relax(); |