diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/trace/ftrace_internal.h | 22 | ||||
| -rw-r--r-- | kernel/trace/ring_buffer.c | 34 |
2 files changed, 13 insertions, 43 deletions
diff --git a/kernel/trace/ftrace_internal.h b/kernel/trace/ftrace_internal.h index 0456e0a3dab1..382775edf690 100644 --- a/kernel/trace/ftrace_internal.h +++ b/kernel/trace/ftrace_internal.h @@ -4,28 +4,6 @@ #ifdef CONFIG_FUNCTION_TRACER -/* - * Traverse the ftrace_global_list, invoking all entries. The reason that we - * can use rcu_dereference_raw_check() is that elements removed from this list - * are simply leaked, so there is no need to interact with a grace-period - * mechanism. The rcu_dereference_raw_check() calls are needed to handle - * concurrent insertions into the ftrace_global_list. - * - * Silly Alpha and silly pointer-speculation compiler optimizations! - */ -#define do_for_each_ftrace_op(op, list) \ - op = rcu_dereference_raw_check(list); \ - do - -/* - * Optimized for just a single item in the list (as that is the normal case). - */ -#define while_for_each_ftrace_op(op) \ - while (likely(op = rcu_dereference_raw_check((op)->next)) && \ - unlikely((op) != &ftrace_list_end)) - -extern struct ftrace_ops __rcu *ftrace_ops_list; -extern struct ftrace_ops ftrace_list_end; extern struct mutex ftrace_lock; extern struct ftrace_ops global_ops; diff --git a/kernel/trace/ring_buffer.c b/kernel/trace/ring_buffer.c index 6f0b42ceeb00..b8e1ca48be50 100644 --- a/kernel/trace/ring_buffer.c +++ b/kernel/trace/ring_buffer.c @@ -193,7 +193,7 @@ rb_event_length(struct ring_buffer_event *event) case RINGBUF_TYPE_DATA: return rb_event_data_length(event); default: - BUG(); + WARN_ON_ONCE(1); } /* not hit */ return 0; @@ -249,7 +249,7 @@ rb_event_data(struct ring_buffer_event *event) { if (extended_time(event)) event = skip_time_extend(event); - BUG_ON(event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX); + WARN_ON_ONCE(event->type_len > RINGBUF_TYPE_DATA_TYPE_LEN_MAX); /* If length is in len field, then array[0] has the data */ if (event->type_len) return (void *)&event->array[0]; @@ -3727,7 +3727,7 @@ rb_update_read_stamp(struct ring_buffer_per_cpu *cpu_buffer, return; default: - BUG(); + RB_WARN_ON(cpu_buffer, 1); } return; } @@ -3757,7 +3757,7 @@ rb_update_iter_read_stamp(struct ring_buffer_iter *iter, return; default: - BUG(); + RB_WARN_ON(iter->cpu_buffer, 1); } return; } @@ -4020,7 +4020,7 @@ rb_buffer_peek(struct ring_buffer_per_cpu *cpu_buffer, u64 *ts, return event; default: - BUG(); + RB_WARN_ON(cpu_buffer, 1); } return NULL; @@ -4034,7 +4034,6 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) struct ring_buffer_per_cpu *cpu_buffer; struct ring_buffer_event *event; int nr_loops = 0; - bool failed = false; if (ts) *ts = 0; @@ -4056,19 +4055,14 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) return NULL; /* - * We repeat when a time extend is encountered or we hit - * the end of the page. Since the time extend is always attached - * to a data event, we should never loop more than three times. - * Once for going to next page, once on time extend, and - * finally once to get the event. - * We should never hit the following condition more than thrice, - * unless the buffer is very small, and there's a writer - * that is causing the reader to fail getting an event. + * As the writer can mess with what the iterator is trying + * to read, just give up if we fail to get an event after + * three tries. The iterator is not as reliable when reading + * the ring buffer with an active write as the consumer is. + * Do not warn if the three failures is reached. */ - if (++nr_loops > 3) { - RB_WARN_ON(cpu_buffer, !failed); + if (++nr_loops > 3) return NULL; - } if (rb_per_cpu_empty(cpu_buffer)) return NULL; @@ -4079,10 +4073,8 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) } event = rb_iter_head_event(iter); - if (!event) { - failed = true; + if (!event) goto again; - } switch (event->type_len) { case RINGBUF_TYPE_PADDING: @@ -4117,7 +4109,7 @@ rb_iter_peek(struct ring_buffer_iter *iter, u64 *ts) return event; default: - BUG(); + RB_WARN_ON(cpu_buffer, 1); } return NULL; |