irq_work: Don't stop the tick with pending works

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>
Acked-by: Steven Rostedt <rostedt@goodmis.org>
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: Paul Gortmaker <paul.gortmaker@windriver.com>

diff --git a/include/linux/irq_work.h b/include/linux/irq_work.h
index 6a9e8f5399e2ab137b3c251eb49349fdc6b333ac..a69704f37204aeecf562e642605cb10905d6639e 100644 (file)
--- 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 64eddd59ed83852262b5655a56e8ebb284dcb119..b3c113a14727211356b20c3cdaa3771bb611cb39 100644 (file)
--- 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;
+
+       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 9e945aa090acbfe57a1a13430550eee45882f188..f249e8c3e58e47410c3fee619f59c94aca4dc2bd 100644 (file)
--- 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 {