diff options
| -rw-r--r-- | include/linux/trace_events.h | 5 | ||||
| -rw-r--r-- | kernel/trace/trace_event_perf.c | 80 |
2 files changed, 54 insertions, 31 deletions
diff --git a/include/linux/trace_events.h b/include/linux/trace_events.h index a6349b76fd39..ca4e67e466a7 100644 --- a/include/linux/trace_events.h +++ b/include/linux/trace_events.h @@ -173,6 +173,11 @@ enum trace_reg { TRACE_REG_PERF_UNREGISTER, TRACE_REG_PERF_OPEN, TRACE_REG_PERF_CLOSE, + /* + * These (ADD/DEL) use a 'boolean' return value, where 1 (true) means a + * custom action was taken and the default action is not to be + * performed. + */ TRACE_REG_PERF_ADD, TRACE_REG_PERF_DEL, #endif diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c index 562fa69df5d3..e73f9ab15939 100644 --- a/kernel/trace/trace_event_perf.c +++ b/kernel/trace/trace_event_perf.c @@ -240,27 +240,41 @@ void perf_trace_destroy(struct perf_event *p_event) int perf_trace_add(struct perf_event *p_event, int flags) { struct trace_event_call *tp_event = p_event->tp_event; - struct hlist_head __percpu *pcpu_list; - struct hlist_head *list; - - pcpu_list = tp_event->perf_events; - if (WARN_ON_ONCE(!pcpu_list)) - return -EINVAL; if (!(flags & PERF_EF_START)) p_event->hw.state = PERF_HES_STOPPED; - list = this_cpu_ptr(pcpu_list); - hlist_add_head_rcu(&p_event->hlist_entry, list); + /* + * If TRACE_REG_PERF_ADD returns false; no custom action was performed + * and we need to take the default action of enqueueing our event on + * the right per-cpu hlist. + */ + if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event)) { + struct hlist_head __percpu *pcpu_list; + struct hlist_head *list; + + pcpu_list = tp_event->perf_events; + if (WARN_ON_ONCE(!pcpu_list)) + return -EINVAL; + + list = this_cpu_ptr(pcpu_list); + hlist_add_head_rcu(&p_event->hlist_entry, list); + } - return tp_event->class->reg(tp_event, TRACE_REG_PERF_ADD, p_event); + return 0; } void perf_trace_del(struct perf_event *p_event, int flags) { struct trace_event_call *tp_event = p_event->tp_event; - hlist_del_rcu(&p_event->hlist_entry); - tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event); + + /* + * If TRACE_REG_PERF_DEL returns false; no custom action was performed + * and we need to take the default action of dequeueing our event from + * the right per-cpu hlist. + */ + if (!tp_event->class->reg(tp_event, TRACE_REG_PERF_DEL, p_event)) + hlist_del_rcu(&p_event->hlist_entry); } void *perf_trace_buf_alloc(int size, struct pt_regs **regs, int *rctxp) @@ -307,14 +321,24 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, struct ftrace_ops *ops, struct pt_regs *pt_regs) { struct ftrace_entry *entry; - struct hlist_head *head; + struct perf_event *event; + struct hlist_head head; struct pt_regs regs; int rctx; - head = this_cpu_ptr(event_function.perf_events); - if (hlist_empty(head)) + if ((unsigned long)ops->private != smp_processor_id()) return; + event = container_of(ops, struct perf_event, ftrace_ops); + + /* + * @event->hlist entry is NULL (per INIT_HLIST_NODE), and all + * the perf code does is hlist_for_each_entry_rcu(), so we can + * get away with simply setting the @head.first pointer in order + * to create a singular list. + */ + head.first = &event->hlist_entry; + #define ENTRY_SIZE (ALIGN(sizeof(struct ftrace_entry) + sizeof(u32), \ sizeof(u64)) - sizeof(u32)) @@ -330,7 +354,7 @@ perf_ftrace_function_call(unsigned long ip, unsigned long parent_ip, entry->ip = ip; entry->parent_ip = parent_ip; perf_trace_buf_submit(entry, ENTRY_SIZE, rctx, TRACE_FN, - 1, ®s, head, NULL); + 1, ®s, &head, NULL); #undef ENTRY_SIZE } @@ -339,8 +363,10 @@ static int perf_ftrace_function_register(struct perf_event *event) { struct ftrace_ops *ops = &event->ftrace_ops; - ops->flags |= FTRACE_OPS_FL_PER_CPU | FTRACE_OPS_FL_RCU; - ops->func = perf_ftrace_function_call; + ops->flags |= FTRACE_OPS_FL_RCU; + ops->func = perf_ftrace_function_call; + ops->private = (void *)(unsigned long)nr_cpu_ids; + return register_ftrace_function(ops); } @@ -352,19 +378,11 @@ static int perf_ftrace_function_unregister(struct perf_event *event) return ret; } -static void perf_ftrace_function_enable(struct perf_event *event) -{ - ftrace_function_local_enable(&event->ftrace_ops); -} - -static void perf_ftrace_function_disable(struct perf_event *event) -{ - ftrace_function_local_disable(&event->ftrace_ops); -} - int perf_ftrace_event_register(struct trace_event_call *call, enum trace_reg type, void *data) { + struct perf_event *event = data; + switch (type) { case TRACE_REG_REGISTER: case TRACE_REG_UNREGISTER: @@ -377,11 +395,11 @@ int perf_ftrace_event_register(struct trace_event_call *call, case TRACE_REG_PERF_CLOSE: return perf_ftrace_function_unregister(data); case TRACE_REG_PERF_ADD: - perf_ftrace_function_enable(data); - return 0; + event->ftrace_ops.private = (void *)(unsigned long)smp_processor_id(); + return 1; case TRACE_REG_PERF_DEL: - perf_ftrace_function_disable(data); - return 0; + event->ftrace_ops.private = (void *)(unsigned long)nr_cpu_ids; + return 1; } return -EINVAL; |