Messages in this thread | ![/](/images/icornerl.gif) | | Subject | Re: [PATCH 5/7] irq_work: Don't stop the tick with pending works | From | Steven Rostedt <> | Date | Wed, 14 Nov 2012 22:59:41 -0500 |
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On Wed, 2012-11-14 at 21:37 +0100, Frederic Weisbecker wrote: > Don't stop the tick if we have pending irq works on the > queue, otherwise if the arch can't raise self-IPIs, we may not > find an opportunity to execute the pending works for a while. > > Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com> > Cc: Peter Zijlstra <peterz@infradead.org> > Cc: Thomas Gleixner <tglx@linutronix.de> > Cc: Ingo Molnar <mingo@kernel.org> > Cc: Andrew Morton <akpm@linux-foundation.org> > Cc: Steven Rostedt <rostedt@goodmis.org> > Cc: Paul Gortmaker <paul.gortmaker@windriver.com> > --- > include/linux/irq_work.h | 6 ++++++ > kernel/irq_work.c | 11 +++++++++++ > kernel/time/tick-sched.c | 3 ++- > 3 files changed, 19 insertions(+), 1 deletions(-) > > diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h > index 6a9e8f5..a69704f 100644 > --- a/include/linux/irq_work.h > +++ b/include/linux/irq_work.h > @@ -20,4 +20,10 @@ bool irq_work_queue(struct irq_work *work); > void irq_work_run(void); > void irq_work_sync(struct irq_work *work); > > +#ifdef CONFIG_IRQ_WORK > +bool irq_work_needs_cpu(void); > +#else > +static bool irq_work_needs_cpu(void) { return false; } > +#endif > + > #endif /* _LINUX_IRQ_WORK_H */ > diff --git a/kernel/irq_work.c b/kernel/irq_work.c > index 64eddd5..b3c113a 100644 > --- a/kernel/irq_work.c > +++ b/kernel/irq_work.c > @@ -99,6 +99,17 @@ bool irq_work_queue(struct irq_work *work) > } > EXPORT_SYMBOL_GPL(irq_work_queue); > > +bool irq_work_needs_cpu(void) > +{ > + struct llist_head *this_list; > + > + this_list = &__get_cpu_var(irq_work_list); > + if (llist_empty(this_list)) > + return false; > +
I wounder if this should just be:
return !llist_empty(&this_cpu_read(irq_work_list));
-- Steve
> + return true; > +} > + > /* > * Run the irq_work entries on this cpu. Requires to be ran from hardirq > * context with local IRQs disabled. > diff --git a/kernel/time/tick-sched.c b/kernel/time/tick-sched.c > index 9e945aa..f249e8c 100644 > --- a/kernel/time/tick-sched.c > +++ b/kernel/time/tick-sched.c > @@ -20,6 +20,7 @@ > #include <linux/profile.h> > #include <linux/sched.h> > #include <linux/module.h> > +#include <linux/irq_work.h> > > #include <asm/irq_regs.h> > > @@ -289,7 +290,7 @@ static ktime_t tick_nohz_stop_sched_tick(struct tick_sched *ts, > } while (read_seqretry(&xtime_lock, seq)); > > if (rcu_needs_cpu(cpu, &rcu_delta_jiffies) || printk_needs_cpu(cpu) || > - arch_needs_cpu(cpu)) { > + arch_needs_cpu(cpu) || irq_work_needs_cpu()) { > next_jiffies = last_jiffies + 1; > delta_jiffies = 1; > } else {
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