diff options
| author | Sebastian Andrzej Siewior <bigeasy@linutronix.de> | 2014-01-31 13:20:31 (GMT) |
|---|---|---|
| committer | Scott Wood <scottwood@freescale.com> | 2015-02-13 22:20:57 (GMT) |
| commit | 66ac3feebc0fa881fc4b9d03110bd257536852e7 (patch) | |
| tree | 59f131743c457e418f24975692ed06817407231d /kernel | |
| parent | ef6bcccdb8ae11d181029a5e2a866140fdc4f1ce (diff) | |
| download | linux-fsl-qoriq-66ac3feebc0fa881fc4b9d03110bd257536852e7.tar.xz | |
irq_work: allow certain work in hard irq context
irq_work is processed in softirq context on -RT because we want to avoid
long latencies which might arise from processing lots of perf events.
The noHZ-full mode requires its callback to be called from real hardirq
context (commit 76c24fb ("nohz: New APIs to re-evaluate the tick on full
dynticks CPUs")). If it is called from a thread context we might get
wrong results for checks like "is_idle_task(current)".
This patch introduces a second list (hirq_work_list) which will be used
if irq_work_run() has been invoked from hardirq context and process only
work items marked with IRQ_WORK_HARD_IRQ.
This patch also removes arch_irq_work_raise() from sparc & powerpc like
it is already done for x86. Atleast for powerpc it is somehow
superfluous because it is called from the timer interrupt which should
invoke update_process_times().
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/irq_work.c | 22 | ||||
| -rw-r--r-- | kernel/time/tick-sched.c | 1 | ||||
| -rw-r--r-- | kernel/timer.c | 2 |
3 files changed, 21 insertions, 4 deletions
diff --git a/kernel/irq_work.c b/kernel/irq_work.c index f6e4377..35d21f9 100644 --- a/kernel/irq_work.c +++ b/kernel/irq_work.c @@ -20,6 +20,9 @@ static DEFINE_PER_CPU(struct llist_head, irq_work_list); +#ifdef CONFIG_PREEMPT_RT_FULL +static DEFINE_PER_CPU(struct llist_head, hirq_work_list); +#endif static DEFINE_PER_CPU(int, irq_work_raised); /* @@ -48,7 +51,11 @@ static bool irq_work_claim(struct irq_work *work) return true; } +#ifdef CONFIG_PREEMPT_RT_FULL +void arch_irq_work_raise(void) +#else void __weak arch_irq_work_raise(void) +#endif { /* * Lame architectures will get the timer tick callback @@ -70,8 +77,12 @@ void irq_work_queue(struct irq_work *work) /* Queue the entry and raise the IPI if needed. */ preempt_disable(); - llist_add(&work->llnode, &__get_cpu_var(irq_work_list)); - +#ifdef CONFIG_PREEMPT_RT_FULL + if (work->flags & IRQ_WORK_HARD_IRQ) + llist_add(&work->llnode, &__get_cpu_var(hirq_work_list)); + else +#endif + llist_add(&work->llnode, &__get_cpu_var(irq_work_list)); /* * If the work is not "lazy" or the tick is stopped, raise the irq * work interrupt (if supported by the arch), otherwise, just wait @@ -115,7 +126,12 @@ static void __irq_work_run(void) __this_cpu_write(irq_work_raised, 0); barrier(); - this_list = &__get_cpu_var(irq_work_list); +#ifdef CONFIG_PREEMPT_RT_FULL + if (in_irq()) + this_list = &__get_cpu_var(hirq_work_list); + else +#endif + this_list = &__get_cpu_var(irq_work_list); if (llist_empty(this_list)) return; diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c index fa4c28b..7e5c94b 100644 --- a/kernel/time/tick-sched.c +++ b/kernel/time/tick-sched.c @@ -221,6 +221,7 @@ static void nohz_full_kick_work_func(struct irq_work *work) static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = { .func = nohz_full_kick_work_func, + .flags = IRQ_WORK_HARD_IRQ, }; /* diff --git a/kernel/timer.c b/kernel/timer.c index a85ac8f..611a597 100644 --- a/kernel/timer.c +++ b/kernel/timer.c @@ -1425,7 +1425,7 @@ void update_process_times(int user_tick) scheduler_tick(); run_local_timers(); rcu_check_callbacks(cpu, user_tick); -#if defined(CONFIG_IRQ_WORK) && !defined(CONFIG_PREEMPT_RT_FULL) +#if defined(CONFIG_IRQ_WORK) if (in_irq()) irq_work_run(); #endif |