[PATCH RT 04/13] net: provide a way to delegate processing a softirq to ksoftirqd
From: Steven Rostedt <rostedt@goodmis.org>
Date: 2016-03-02 15:49:11
Also in:
lkml
Subsystem:
networking [general], the rest · Maintainers:
"David S. Miller", Eric Dumazet, Jakub Kicinski, Paolo Abeni, Linus Torvalds
3.12.54-rt74-rc1 stable review patch. If anyone has any objections, please let me know. ------------------ From: Sebastian Andrzej Siewior <bigeasy@linutronix.de> If the NET_RX uses up all of his budget it moves the following NAPI invocations into the `ksoftirqd`. On -RT it does not do so. Instead it rises the NET_RX softirq in its current context again. In order to get closer to mainline's behaviour this patch provides __raise_softirq_irqoff_ksoft() which raises the softirq in the ksoftird. Cc: stable-rt@vger.kernel.org Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> Signed-off-by: Steven Rostedt <rostedt@goodmis.org> --- include/linux/interrupt.h | 8 ++++++++ kernel/softirq.c | 21 +++++++++++++++++++++ net/core/dev.c | 2 +- 3 files changed, 30 insertions(+), 1 deletion(-)
diff --git a/include/linux/interrupt.h b/include/linux/interrupt.h
index 750d1e6cbe36..5cd89e325324 100644
--- a/include/linux/interrupt.h
+++ b/include/linux/interrupt.h@@ -428,6 +428,14 @@ extern void thread_do_softirq(void); extern void open_softirq(int nr, void (*action)(struct softirq_action *)); extern void softirq_init(void); extern void __raise_softirq_irqoff(unsigned int nr); +#ifdef CONFIG_PREEMPT_RT_FULL +extern void __raise_softirq_irqoff_ksoft(unsigned int nr); +#else +static inline void __raise_softirq_irqoff_ksoft(unsigned int nr) +{ + __raise_softirq_irqoff(nr); +} +#endif extern void raise_softirq_irqoff(unsigned int nr); extern void raise_softirq(unsigned int nr);
diff --git a/kernel/softirq.c b/kernel/softirq.c
index c10594c778fe..cce9723c5a18 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c@@ -692,6 +692,27 @@ void __raise_softirq_irqoff(unsigned int nr) } /* + * Same as __raise_softirq_irqoff() but will process them in ksoftirqd + */ +void __raise_softirq_irqoff_ksoft(unsigned int nr) +{ + unsigned int mask; + + if (WARN_ON_ONCE(!__this_cpu_read(ksoftirqd) || + !__this_cpu_read(ktimer_softirqd))) + return; + mask = 1UL << nr; + + trace_softirq_raise(nr); + or_softirq_pending(mask); + if (mask & TIMER_SOFTIRQS) + __this_cpu_read(ktimer_softirqd)->softirqs_raised |= mask; + else + __this_cpu_read(ksoftirqd)->softirqs_raised |= mask; + wakeup_proper_softirq(nr); +} + +/* * This function must run with irqs disabled! */ void raise_softirq_irqoff(unsigned int nr)
diff --git a/net/core/dev.c b/net/core/dev.c
index cfec8a542d35..ee08da0fe0d7 100644
--- a/net/core/dev.c
+++ b/net/core/dev.c@@ -4428,7 +4428,7 @@ out: softnet_break: sd->time_squeeze++; - __raise_softirq_irqoff(NET_RX_SOFTIRQ); + __raise_softirq_irqoff_ksoft(NET_RX_SOFTIRQ); goto out; }
--
2.7.0