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-rw-r--r--kernel/softirq.c34
1 files changed, 28 insertions, 6 deletions
diff --git a/kernel/softirq.c b/kernel/softirq.c
index 57d3f67f6f38..d105a82543d0 100644
--- a/kernel/softirq.c
+++ b/kernel/softirq.c
@@ -21,8 +21,10 @@
21#include <linux/freezer.h> 21#include <linux/freezer.h>
22#include <linux/kthread.h> 22#include <linux/kthread.h>
23#include <linux/rcupdate.h> 23#include <linux/rcupdate.h>
24#include <linux/ftrace.h>
24#include <linux/smp.h> 25#include <linux/smp.h>
25#include <linux/tick.h> 26#include <linux/tick.h>
27#include <trace/irq.h>
26 28
27#include <asm/irq.h> 29#include <asm/irq.h>
28/* 30/*
@@ -52,6 +54,11 @@ static struct softirq_action softirq_vec[NR_SOFTIRQS] __cacheline_aligned_in_smp
52 54
53static DEFINE_PER_CPU(struct task_struct *, ksoftirqd); 55static DEFINE_PER_CPU(struct task_struct *, ksoftirqd);
54 56
57char *softirq_to_name[NR_SOFTIRQS] = {
58 "HI", "TIMER", "NET_TX", "NET_RX", "BLOCK",
59 "TASKLET", "SCHED", "HRTIMER", "RCU"
60};
61
55/* 62/*
56 * we cannot loop indefinitely here to avoid userspace starvation, 63 * we cannot loop indefinitely here to avoid userspace starvation,
57 * but we also don't want to introduce a worst case 1/HZ latency 64 * 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)
79 WARN_ON_ONCE(in_irq()); 86 WARN_ON_ONCE(in_irq());
80 87
81 raw_local_irq_save(flags); 88 raw_local_irq_save(flags);
82 add_preempt_count(SOFTIRQ_OFFSET); 89 /*
90 * The preempt tracer hooks into add_preempt_count and will break
91 * lockdep because it calls back into lockdep after SOFTIRQ_OFFSET
92 * is set and before current->softirq_enabled is cleared.
93 * We must manually increment preempt_count here and manually
94 * call the trace_preempt_off later.
95 */
96 preempt_count() += SOFTIRQ_OFFSET;
83 /* 97 /*
84 * Were softirqs turned off above: 98 * Were softirqs turned off above:
85 */ 99 */
86 if (softirq_count() == SOFTIRQ_OFFSET) 100 if (softirq_count() == SOFTIRQ_OFFSET)
87 trace_softirqs_off(ip); 101 trace_softirqs_off(ip);
88 raw_local_irq_restore(flags); 102 raw_local_irq_restore(flags);
103
104 if (preempt_count() == SOFTIRQ_OFFSET)
105 trace_preempt_off(CALLER_ADDR0, get_parent_ip(CALLER_ADDR1));
89} 106}
90#else /* !CONFIG_TRACE_IRQFLAGS */ 107#else /* !CONFIG_TRACE_IRQFLAGS */
91static inline void __local_bh_disable(unsigned long ip) 108static inline void __local_bh_disable(unsigned long ip)
@@ -169,6 +186,9 @@ EXPORT_SYMBOL(local_bh_enable_ip);
169 */ 186 */
170#define MAX_SOFTIRQ_RESTART 10 187#define MAX_SOFTIRQ_RESTART 10
171 188
189DEFINE_TRACE(softirq_entry);
190DEFINE_TRACE(softirq_exit);
191
172asmlinkage void __do_softirq(void) 192asmlinkage void __do_softirq(void)
173{ 193{
174 struct softirq_action *h; 194 struct softirq_action *h;
@@ -180,7 +200,7 @@ asmlinkage void __do_softirq(void)
180 account_system_vtime(current); 200 account_system_vtime(current);
181 201
182 __local_bh_disable((unsigned long)__builtin_return_address(0)); 202 __local_bh_disable((unsigned long)__builtin_return_address(0));
183 trace_softirq_enter(); 203 lockdep_softirq_enter();
184 204
185 cpu = smp_processor_id(); 205 cpu = smp_processor_id();
186restart: 206restart:
@@ -195,12 +215,14 @@ restart:
195 if (pending & 1) { 215 if (pending & 1) {
196 int prev_count = preempt_count(); 216 int prev_count = preempt_count();
197 217
218 trace_softirq_entry(h, softirq_vec);
198 h->action(h); 219 h->action(h);
199 220 trace_softirq_exit(h, softirq_vec);
200 if (unlikely(prev_count != preempt_count())) { 221 if (unlikely(prev_count != preempt_count())) {
201 printk(KERN_ERR "huh, entered softirq %td %p" 222 printk(KERN_ERR "huh, entered softirq %td %s %p"
202 "with preempt_count %08x," 223 "with preempt_count %08x,"
203 " exited with %08x?\n", h - softirq_vec, 224 " exited with %08x?\n", h - softirq_vec,
225 softirq_to_name[h - softirq_vec],
204 h->action, prev_count, preempt_count()); 226 h->action, prev_count, preempt_count());
205 preempt_count() = prev_count; 227 preempt_count() = prev_count;
206 } 228 }
@@ -220,7 +242,7 @@ restart:
220 if (pending) 242 if (pending)
221 wakeup_softirqd(); 243 wakeup_softirqd();
222 244
223 trace_softirq_exit(); 245 lockdep_softirq_exit();
224 246
225 account_system_vtime(current); 247 account_system_vtime(current);
226 _local_bh_enable(); 248 _local_bh_enable();
@@ -496,7 +518,7 @@ static int __try_remote_softirq(struct call_single_data *cp, int cpu, int softir
496 cp->flags = 0; 518 cp->flags = 0;
497 cp->priv = softirq; 519 cp->priv = softirq;
498 520
499 __smp_call_function_single(cpu, cp); 521 __smp_call_function_single(cpu, cp, 0);
500 return 0; 522 return 0;
501 } 523 }
502 return 1; 524 return 1;