Re: [PATCH RT] convert RCU Preempt tasklet into softirq.
From: Paul E. McKenney <hidden>
Date: 2007-06-07 21:02:58
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On Thu, Jun 07, 2007 at 02:26:59PM -0400, Steven Rostedt wrote:
Following Dipankar's lead, I converted the tasklet in rcupreempt.c into a softirq. I've compiled and booted with this patch, but ran no other tests.
I should be able to run rcutorture on it.
Paul, I'm disappointed, this was so trivial I didn't get a chance to learn anything ;-)
;-) Some nits below. Thanx, Paul
quoted hunk ↗ jump to hunk
Signed-off-by: Steven Rostedt <rostedt@goodmis.org> Index: linux-2.6.21-rt9/include/linux/rcupreempt.h ===================================================================--- linux-2.6.21-rt9.orig/include/linux/rcupreempt.h +++ linux-2.6.21-rt9/include/linux/rcupreempt.h@@ -63,7 +63,9 @@ extern void rcu_check_callbacks(int cpu, extern void rcu_restart_cpu(int cpu); extern long rcu_batches_completed(void); -extern void rcu_process_callbacks(unsigned long unused); +struct softirq_action; + +extern void rcu_process_callbacks(struct softirq_action *unused);
I don't understand why the above is needed -- interrupt.h is included, and the use of rcu_process_callbacks() follows the definition.
quoted hunk ↗ jump to hunk
#endif /* __KERNEL__ */ #endif /* __LINUX_RCUPREEMPT_H */ Index: linux-2.6.21-rt9/kernel/rcupreempt.c ===================================================================--- linux-2.6.21-rt9.orig/kernel/rcupreempt.c +++ linux-2.6.21-rt9/kernel/rcupreempt.c@@ -57,7 +57,6 @@ struct rcu_data { raw_spinlock_t lock; long completed; /* Number of last completed batch. */ - struct tasklet_struct rcu_tasklet; struct rcu_head *nextlist; struct rcu_head **nexttail; struct rcu_head *waitlist;@@ -255,7 +254,7 @@ void rcu_check_callbacks(int cpu, int us spin_unlock_irqrestore(&rcu_data.lock, oldirq); } else { spin_unlock_irqrestore(&rcu_data.lock, oldirq); - tasklet_schedule(&rcu_data.rcu_tasklet); + raise_softirq(RCU_SOFTIRQ); } }@@ -279,7 +278,7 @@ void rcu_advance_callbacks(int cpu, int spin_unlock_irqrestore(&rcu_data.lock, oldirq); } -void rcu_process_callbacks(unsigned long unused) +void rcu_process_callbacks(struct softirq_action *unused) { unsigned long flags; struct rcu_head *next, *list;@@ -367,7 +366,7 @@ void __init __rcu_init(void) rcu_data.waittail = &rcu_data.waitlist; rcu_data.donelist = NULL; rcu_data.donetail = &rcu_data.donelist; - tasklet_init(&rcu_data.rcu_tasklet, rcu_process_callbacks, 0UL); + open_softirq(RCU_SOFTIRQ, rcu_process_callbacks, NULL); } /* -To unsubscribe from this list: send the line "unsubscribe linux-rt-users" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html