diff options
Diffstat (limited to 'kernel/trace/trace.c')
-rw-r--r-- | kernel/trace/trace.c | 113 |
1 files changed, 77 insertions, 36 deletions
diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 6a1c76b..b542f88 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -42,6 +42,20 @@ unsigned long __read_mostly tracing_max_latency = (cycle_t)ULONG_MAX; unsigned long __read_mostly tracing_thresh; +static DEFINE_PER_CPU(local_t, ftrace_cpu_disabled); + +static inline void ftrace_disable_cpu(void) +{ + preempt_disable(); + local_inc(&__get_cpu_var(ftrace_cpu_disabled)); +} + +static inline void ftrace_enable_cpu(void) +{ + local_dec(&__get_cpu_var(ftrace_cpu_disabled)); + preempt_enable(); +} + static cpumask_t __read_mostly tracing_buffer_mask; #define for_each_tracing_cpu(cpu) \ @@ -406,7 +420,9 @@ update_max_tr(struct trace_array *tr, struct task_struct *tsk, int cpu) tr->buffer = max_tr.buffer; max_tr.buffer = buf; + ftrace_disable_cpu(); ring_buffer_reset(tr->buffer); + ftrace_enable_cpu(); __update_max_tr(tr, tsk, cpu); __raw_spin_unlock(&ftrace_max_lock); @@ -428,9 +444,13 @@ update_max_tr_single(struct trace_array *tr, struct task_struct *tsk, int cpu) WARN_ON_ONCE(!irqs_disabled()); __raw_spin_lock(&ftrace_max_lock); + ftrace_disable_cpu(); + ring_buffer_reset(max_tr.buffer); ret = ring_buffer_swap_cpu(max_tr.buffer, tr->buffer, cpu); + ftrace_enable_cpu(); + WARN_ON_ONCE(ret); __update_max_tr(tr, tsk, cpu); @@ -543,7 +563,9 @@ void unregister_tracer(struct tracer *type) void tracing_reset(struct trace_array *tr, int cpu) { + ftrace_disable_cpu(); ring_buffer_reset_cpu(tr->buffer, cpu); + ftrace_enable_cpu(); } #define SAVED_CMDLINES 128 @@ -654,6 +676,10 @@ trace_function(struct trace_array *tr, struct trace_array_cpu *data, struct ftrace_entry *entry; unsigned long irq_flags; + /* If we are reading the ring buffer, don't trace */ + if (unlikely(local_read(&__get_cpu_var(ftrace_cpu_disabled)))) + return; + event = ring_buffer_lock_reserve(tr->buffer, sizeof(*entry), &irq_flags); if (!event) @@ -870,8 +896,14 @@ enum trace_file_type { static void trace_iterator_increment(struct trace_iterator *iter, int cpu) { + /* Don't allow ftrace to trace into the ring buffers */ + ftrace_disable_cpu(); + iter->idx++; - ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); + if (iter->buffer_iter[iter->cpu]) + ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); + + ftrace_enable_cpu(); } static struct trace_entry * @@ -880,9 +912,19 @@ peek_next_entry(struct trace_iterator *iter, int cpu, u64 *ts) struct ring_buffer_event *event; struct ring_buffer_iter *buf_iter = iter->buffer_iter[cpu]; - event = ring_buffer_iter_peek(buf_iter, ts); + /* Don't allow ftrace to trace into the ring buffers */ + ftrace_disable_cpu(); + + if (buf_iter) + event = ring_buffer_iter_peek(buf_iter, ts); + else + event = ring_buffer_peek(iter->tr->buffer, cpu, ts); + + ftrace_enable_cpu(); + return event ? ring_buffer_event_data(event) : NULL; } + static struct trace_entry * __find_next_entry(struct trace_iterator *iter, int *ent_cpu, u64 *ent_ts) { @@ -938,7 +980,10 @@ static void *find_next_entry_inc(struct trace_iterator *iter) static void trace_consume(struct trace_iterator *iter) { + /* Don't allow ftrace to trace into the ring buffers */ + ftrace_disable_cpu(); ring_buffer_consume(iter->tr->buffer, iter->cpu, &iter->ts); + ftrace_enable_cpu(); } static void *s_next(struct seq_file *m, void *v, loff_t *pos) @@ -991,10 +1036,14 @@ static void *s_start(struct seq_file *m, loff_t *pos) iter->cpu = 0; iter->idx = -1; + ftrace_disable_cpu(); + for_each_tracing_cpu(cpu) { ring_buffer_iter_reset(iter->buffer_iter[cpu]); } + ftrace_enable_cpu(); + for (p = iter; p && l < *pos; p = s_next(m, p, &l)) ; @@ -1242,7 +1291,16 @@ void trace_seq_print_cont(struct trace_seq *s, struct trace_iterator *iter) cont = (struct trace_field_cont *)ent; if (ok) ok = (trace_seq_printf(s, "%s", cont->buf) > 0); - ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); + + ftrace_disable_cpu(); + + if (iter->buffer_iter[iter->cpu]) + ring_buffer_read(iter->buffer_iter[iter->cpu], NULL); + else + ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL); + + ftrace_enable_cpu(); + ent = peek_next_entry(iter, iter->cpu, NULL); } while (ent && ent->type == TRACE_CONT); @@ -1683,9 +1741,15 @@ static int trace_empty(struct trace_iterator *iter) int cpu; for_each_tracing_cpu(cpu) { - if (!ring_buffer_iter_empty(iter->buffer_iter[cpu])) - return 0; + if (iter->buffer_iter[cpu]) { + if (!ring_buffer_iter_empty(iter->buffer_iter[cpu])) + return 0; + } else { + if (!ring_buffer_empty_cpu(iter->tr->buffer, cpu)) + return 0; + } } + return TRACE_TYPE_HANDLED; } @@ -1776,8 +1840,10 @@ __tracing_open(struct inode *inode, struct file *file, int *ret) iter->pos = -1; for_each_tracing_cpu(cpu) { + iter->buffer_iter[cpu] = ring_buffer_read_start(iter->tr->buffer, cpu); + if (!iter->buffer_iter[cpu]) goto fail_buffer; } @@ -2341,7 +2407,6 @@ static atomic_t tracing_reader; static int tracing_open_pipe(struct inode *inode, struct file *filp) { struct trace_iterator *iter; - int cpu; if (tracing_disabled) return -ENODEV; @@ -2362,38 +2427,17 @@ static int tracing_open_pipe(struct inode *inode, struct file *filp) iter->trace = current_trace; filp->private_data = iter; - for_each_tracing_cpu(cpu) { - iter->buffer_iter[cpu] = - ring_buffer_read_start(iter->tr->buffer, cpu); - if (!iter->buffer_iter[cpu]) - goto fail_buffer; - } - if (iter->trace->pipe_open) iter->trace->pipe_open(iter); mutex_unlock(&trace_types_lock); return 0; - - fail_buffer: - for_each_tracing_cpu(cpu) { - if (iter->buffer_iter[cpu]) - ring_buffer_read_finish(iter->buffer_iter[cpu]); - } - mutex_unlock(&trace_types_lock); - - return -ENOMEM; } static int tracing_release_pipe(struct inode *inode, struct file *file) { struct trace_iterator *iter = file->private_data; - int cpu; - for_each_tracing_cpu(cpu) { - if (iter->buffer_iter[cpu]) - ring_buffer_read_finish(iter->buffer_iter[cpu]); - } kfree(iter); atomic_dec(&tracing_reader); @@ -2429,7 +2473,6 @@ tracing_read_pipe(struct file *filp, char __user *ubuf, size_t cnt, loff_t *ppos) { struct trace_iterator *iter = filp->private_data; - unsigned long flags; #ifdef CONFIG_FTRACE int ftrace_save; #endif @@ -2528,7 +2571,6 @@ waitagain: ftrace_enabled = 0; #endif smp_wmb(); - ring_buffer_lock(iter->tr->buffer, &flags); while (find_next_entry_inc(iter) != NULL) { enum print_line_t ret; @@ -2547,7 +2589,6 @@ waitagain: break; } - ring_buffer_unlock(iter->tr->buffer, flags); #ifdef CONFIG_FTRACE ftrace_enabled = ftrace_save; #endif @@ -3010,8 +3051,8 @@ void ftrace_dump(void) static struct trace_iterator iter; static cpumask_t mask; static int dump_ran; - unsigned long flags, irq_flags; - int cnt = 0; + unsigned long flags; + int cnt = 0, cpu; /* only one dump */ spin_lock_irqsave(&ftrace_dump_lock, flags); @@ -3023,6 +3064,10 @@ void ftrace_dump(void) /* No turning back! */ ftrace_kill_atomic(); + for_each_tracing_cpu(cpu) { + atomic_inc(&global_trace.data[cpu]->disabled); + } + printk(KERN_TRACE "Dumping ftrace buffer:\n"); iter.tr = &global_trace; @@ -3037,8 +3082,6 @@ void ftrace_dump(void) cpus_clear(mask); - ring_buffer_lock(iter.tr->buffer, &irq_flags); - while (!trace_empty(&iter)) { if (!cnt) @@ -3066,8 +3109,6 @@ void ftrace_dump(void) else printk(KERN_TRACE "---------------------------------\n"); - ring_buffer_unlock(iter.tr->buffer, irq_flags); - out: spin_unlock_irqrestore(&ftrace_dump_lock, flags); } |