Re: [PATCH] rcu: Eliminate softirq processing from rcutree

From: Mike Galbraith
Date: Thu Dec 26 2013 - 05:03:53 EST


On Wed, 2013-12-25 at 04:07 +0100, Mike Galbraith wrote:
> On Tue, 2013-12-24 at 11:36 -0800, Paul E. McKenney wrote:

> > So which code do you think deserves the big lump of coal? ;-)
>
> Sebastian's NO_HZ_FULL locking fixes.

Whack-a-mole hasn't yet dug up any new moles.

---
kernel/timer.c | 4 ++++
1 file changed, 4 insertions(+)

Index: linux-2.6/kernel/timer.c
===================================================================
--- linux-2.6.orig/kernel/timer.c
+++ linux-2.6/kernel/timer.c
@@ -764,7 +764,9 @@ __mod_timer(struct timer_list *timer, un
timer_stats_timer_set_start_info(timer);
BUG_ON(!timer->function);

+ local_irq_disable_rt();
base = lock_timer_base(timer, &flags);
+ local_irq_enable_rt();

ret = detach_if_pending(timer, base, false);
if (!ret && pending_only)
@@ -1198,7 +1200,9 @@ static inline void __run_timers(struct t
{
struct timer_list *timer;

+ local_irq_disable_rt();
spin_lock_irq(&base->lock);
+ local_irq_enable_rt();
while (time_after_eq(jiffies, base->timer_jiffies)) {
struct list_head work_list;
struct list_head *head = &work_list;
---
kernel/time/tick-sched.c | 2 ++
1 file changed, 2 insertions(+)

Index: linux-2.6/kernel/time/tick-sched.c
===================================================================
--- linux-2.6.orig/kernel/time/tick-sched.c
+++ linux-2.6/kernel/time/tick-sched.c
@@ -216,7 +216,9 @@ void __tick_nohz_full_check(void)

static void nohz_full_kick_work_func(struct irq_work *work)
{
+ local_irq_disable_rt();
__tick_nohz_full_check();
+ local_irq_enable_rt();
}

static DEFINE_PER_CPU(struct irq_work, nohz_full_kick_work) = {



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