Merge branch 'locking-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git...
[linux-2.6.git] / kernel / softirq.c
index accc85197c496940b587fb4b7037676f98f6fa6a..2fecefacdc5bc56917c13369420625a919e73c14 100644 (file)
 #include <linux/freezer.h>
 #include <linux/kthread.h>
 #include <linux/rcupdate.h>
+#include <linux/ftrace.h>
 #include <linux/smp.h>
 #include <linux/tick.h>
+#include <trace/irq.h>
 
 #include <asm/irq.h>
 /*
@@ -52,6 +54,11 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
 
 static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
 
+char *softirq_to_name[NR_SOFTIRQS] = {
+       "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK",
+       "TASKLET", "SCHED", "HRTIMER",  "RCU"
+};
+
 /*
  * we cannot loop indefinitely here to avoid userspace starvation,
  * but we also don't want to introduce a worst case 1/HZ latency
@@ -79,13 +86,23 @@ static void __local_bh_disable(unsigned long ip)
        WARN_ON_ONCE(in_irq());
 
        raw_local_irq_save(flags);
-       add_preempt_count(SOFTIRQ_OFFSET);
+       /*
+        * The preempt tracer hooks into add_preempt_count and will break
+        * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
+        * is set and before current->softirq_enabled is cleared.
+        * We must manually increment preempt_count here and manually
+        * call the trace_preempt_off later.
+        */
+       preempt_count() += SOFTIRQ_OFFSET;
        /*
         * Were softirqs turned off above:
         */
        if (softirq_count() == SOFTIRQ_OFFSET)
                trace_softirqs_off(ip);
        raw_local_irq_restore(flags);
+
+       if (preempt_count() == SOFTIRQ_OFFSET)
+               trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
 }
 #else /* !CONFIG_TRACE_IRQFLAGS */
 static inline void __local_bh_disable(unsigned long ip)
@@ -169,6 +186,9 @@ EXPORT_SYMBOL(local_bh_enable_ip);
  */
 #define MAX_SOFTIRQ_RESTART 10
 
+DEFINE_TRACE(softirq_entry);
+DEFINE_TRACE(softirq_exit);
+
 asmlinkage void __do_softirq(void)
 {
        struct softirq_action *h;
@@ -195,12 +215,14 @@ restart:
                if (pending & 1) {
                        int prev_count = preempt_count();
 
+                       trace_softirq_entry(h, softirq_vec);
                        h->action(h);
-
+                       trace_softirq_exit(h, softirq_vec);
                        if (unlikely(prev_count != preempt_count())) {
-                               printk(KERN_ERR "huh, entered softirq %td %p"
+                               printk(KERN_ERR "huh, entered softirq %td %s %p"
                                       "with preempt_count %08x,"
                                       " exited with %08x?\n", h - softirq_vec,
+                                      softirq_to_name[h - softirq_vec],
                                       h->action, prev_count, preempt_count());
                                preempt_count() = prev_count;
                        }
@@ -496,7 +518,7 @@ static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softir
                cp->flags = 0;
                cp->priv = softirq;
 
-               __smp_call_function_single(cpu, cp);
+               __smp_call_function_single(cpu, cp, 0);
                return 0;
        }
        return 1;