X-Git-Url: http://git.cascardo.info/?a=blobdiff_plain;f=kernel%2Fsoftirq.c;h=66762645f9e86c30505610736f0380a2cdd1ae00;hb=df610d678893c85b82d3a68eea0d87dd4e03e615;hp=17caf4b63342d7839528f367b283a386413b0362;hpb=90516d89cd02cbd18e87b9add68c448cd54579a8;p=cascardo%2Flinux.git

diff --git a/kernel/softirq.c b/kernel/softirq.c
index 17caf4b63342..66762645f9e8 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -77,6 +77,17 @@ static void wakeup_softirqd(void)
 		wake_up_process(tsk);
 }
 
+/*
+ * If ksoftirqd is scheduled, we do not want to process pending softirqs
+ * right now. Let ksoftirqd handle this at its own rate, to get fairness.
+ */
+static bool ksoftirqd_running(void)
+{
+	struct task_struct *tsk = __this_cpu_read(ksoftirqd);
+
+	return tsk && (tsk->state == TASK_RUNNING);
+}
+
 /*
  * preempt_count and SOFTIRQ_OFFSET usage:
  * - preempt_count is changed by SOFTIRQ_OFFSET on entering or leaving
@@ -313,7 +324,7 @@ asmlinkage __visible void do_softirq(void)
 
 	pending = local_softirq_pending();
 
-	if (pending)
+	if (pending && !ksoftirqd_running())
 		do_softirq_own_stack();
 
 	local_irq_restore(flags);
@@ -340,6 +351,9 @@ void irq_enter(void)
 
 static inline void invoke_softirq(void)
 {
+	if (ksoftirqd_running())
+		return;
+
 	if (!force_irqthreads) {
 #ifdef CONFIG_HAVE_IRQ_EXIT_ON_IRQ_STACK
 		/*
@@ -700,7 +714,7 @@ void tasklet_kill_immediate(struct tasklet_struct *t, unsigned int cpu)
 	BUG();
 }
 
-static void takeover_tasklets(unsigned int cpu)
+static int takeover_tasklets(unsigned int cpu)
 {
 	/* CPU is dead, so no lock needed. */
 	local_irq_disable();
@@ -723,27 +737,12 @@ static void takeover_tasklets(unsigned int cpu)
 	raise_softirq_irqoff(HI_SOFTIRQ);
 
 	local_irq_enable();
+	return 0;
 }
+#else
+#define takeover_tasklets	NULL
 #endif /* CONFIG_HOTPLUG_CPU */
 
-static int cpu_callback(struct notifier_block *nfb, unsigned long action,
-			void *hcpu)
-{
-	switch (action) {
-#ifdef CONFIG_HOTPLUG_CPU
-	case CPU_DEAD:
-	case CPU_DEAD_FROZEN:
-		takeover_tasklets((unsigned long)hcpu);
-		break;
-#endif /* CONFIG_HOTPLUG_CPU */
-	}
-	return NOTIFY_OK;
-}
-
-static struct notifier_block cpu_nfb = {
-	.notifier_call = cpu_callback
-};
-
 static struct smp_hotplug_thread softirq_threads = {
 	.store			= &ksoftirqd,
 	.thread_should_run	= ksoftirqd_should_run,
@@ -753,8 +752,8 @@ static struct smp_hotplug_thread softirq_threads = {
 
 static __init int spawn_ksoftirqd(void)
 {
-	register_cpu_notifier(&cpu_nfb);
-
+	cpuhp_setup_state_nocalls(CPUHP_SOFTIRQ_DEAD, "softirq:dead", NULL,
+				  takeover_tasklets);
 	BUG_ON(smpboot_register_percpu_thread(&softirq_threads));
 
 	return 0;