perf, trace: Optimize tracepoints by using per-tracepoint-per-cpu hlist to track...

[net-next-2.6.git] / kernel / trace / trace_event_perf.c

diff --git a/kernel/trace/trace_event_perf.c b/kernel/trace/trace_event_perf.c
index a1304f8c4440d768d36648483e790bb0b56f2434..39d5ea7b0653540d2852a55349944824948e51f5 100644 (file)
--- a/kernel/trace/trace_event_perf.c
+++ b/kernel/trace/trace_event_perf.c
@@ -23,14 +23,25 @@ typedef typeof(unsigned long [PERF_MAX_TRACE_SIZE / sizeof(unsigned long)])
 /* Count the events in use (per event id, not per instance) */
 static int     total_ref_count;
 
-static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
+static int perf_trace_event_init(struct ftrace_event_call *tp_event,
+                                struct perf_event *p_event)
 {
+       struct hlist_head *list;
        int ret = -ENOMEM;
+       int cpu;
 
-       if (event->perf_refcount++ > 0) {
-               event->perf_data = NULL;
+       p_event->tp_event = tp_event;
+       if (tp_event->perf_refcount++ > 0)
                return 0;
-       }
+
+       list = alloc_percpu(struct hlist_head);
+       if (!list)
+               goto fail;
+
+       for_each_possible_cpu(cpu)
+               INIT_HLIST_HEAD(per_cpu_ptr(list, cpu));
+
+       tp_event->perf_events = list;
 
        if (!total_ref_count) {
                char *buf;
@@ -39,20 +50,20 @@ static int perf_trace_event_enable(struct ftrace_event_call *event, void *data)
                for (i = 0; i < 4; i++) {
                        buf = (char *)alloc_percpu(perf_trace_t);
                        if (!buf)
-                               goto fail_buf;
+                               goto fail;
 
-                       rcu_assign_pointer(perf_trace_buf[i], buf);
+                       perf_trace_buf[i] = buf;
                }
        }
 
-       ret = event->perf_event_enable(event);
-       if (!ret) {
-               event->perf_data = data;
-               total_ref_count++;
-               return 0;
-       }
+       ret = tp_event->perf_event_enable(tp_event);
+       if (ret)
+               goto fail;
 
-fail_buf:
+       total_ref_count++;
+       return 0;
+
+fail:
        if (!total_ref_count) {
                int i;
 
@@ -61,21 +72,26 @@ fail_buf:
                        perf_trace_buf[i] = NULL;
                }
        }
-       event->perf_refcount--;
+
+       if (!--tp_event->perf_refcount) {
+               free_percpu(tp_event->perf_events);
+               tp_event->perf_events = NULL;
+       }
 
        return ret;
 }
 
-int perf_trace_enable(int event_id, void *data)
+int perf_trace_init(struct perf_event *p_event)
 {
-       struct ftrace_event_call *event;
+       struct ftrace_event_call *tp_event;
+       int event_id = p_event->attr.config;
        int ret = -EINVAL;
 
        mutex_lock(&event_mutex);
-       list_for_each_entry(event, &ftrace_events, list) {
-               if (event->id == event_id && event->perf_event_enable &&
-                   try_module_get(event->mod)) {
-                       ret = perf_trace_event_enable(event, data);
+       list_for_each_entry(tp_event, &ftrace_events, list) {
+               if (tp_event->id == event_id && tp_event->perf_event_enable &&
+                   try_module_get(tp_event->mod)) {
+                       ret = perf_trace_event_init(tp_event, p_event);
                        break;
                }
        }
@@ -84,53 +100,52 @@ int perf_trace_enable(int event_id, void *data)
        return ret;
 }
 
-static void perf_trace_event_disable(struct ftrace_event_call *event)
+int perf_trace_enable(struct perf_event *p_event)
 {
-       if (--event->perf_refcount > 0)
-               return;
+       struct ftrace_event_call *tp_event = p_event->tp_event;
+       struct hlist_head *list;
 
-       event->perf_event_disable(event);
+       list = tp_event->perf_events;
+       if (WARN_ON_ONCE(!list))
+               return -EINVAL;
 
-       if (!--total_ref_count) {
-               char *buf[4];
-               int i;
-
-               for (i = 0; i < 4; i++) {
-                       buf[i] = perf_trace_buf[i];
-                       rcu_assign_pointer(perf_trace_buf[i], NULL);
-               }
+       list = per_cpu_ptr(list, smp_processor_id());
+       hlist_add_head_rcu(&p_event->hlist_entry, list);
 
-               /*
-                * Ensure every events in profiling have finished before
-                * releasing the buffers
-                */
-               synchronize_sched();
+       return 0;
+}
 
-               for (i = 0; i < 4; i++)
-                       free_percpu(buf[i]);
-       }
+void perf_trace_disable(struct perf_event *p_event)
+{
+       hlist_del_rcu(&p_event->hlist_entry);
 }
 
-void perf_trace_disable(int event_id)
+void perf_trace_destroy(struct perf_event *p_event)
 {
-       struct ftrace_event_call *event;
+       struct ftrace_event_call *tp_event = p_event->tp_event;
+       int i;
 
-       mutex_lock(&event_mutex);
-       list_for_each_entry(event, &ftrace_events, list) {
-               if (event->id == event_id) {
-                       perf_trace_event_disable(event);
-                       module_put(event->mod);
-                       break;
+       if (--tp_event->perf_refcount > 0)
+               return;
+
+       tp_event->perf_event_disable(tp_event);
+
+       free_percpu(tp_event->perf_events);
+       tp_event->perf_events = NULL;
+
+       if (!--total_ref_count) {
+               for (i = 0; i < 4; i++) {
+                       free_percpu(perf_trace_buf[i]);
+                       perf_trace_buf[i] = NULL;
                }
        }
-       mutex_unlock(&event_mutex);
 }
 
 __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
                                       struct pt_regs *regs, int *rctxp)
 {
        struct trace_entry *entry;
-       char *trace_buf, *raw_data;
+       char *raw_data;
        int pc;
 
        BUILD_BUG_ON(PERF_MAX_TRACE_SIZE % sizeof(unsigned long));
@@ -139,13 +154,9 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
 
        *rctxp = perf_swevent_get_recursion_context();
        if (*rctxp < 0)
-               goto err_recursion;
-
-       trace_buf = rcu_dereference_sched(perf_trace_buf[*rctxp]);
-       if (!trace_buf)
-               goto err;
+               return NULL;
 
-       raw_data = per_cpu_ptr(trace_buf, smp_processor_id());
+       raw_data = per_cpu_ptr(perf_trace_buf[*rctxp], smp_processor_id());
 
        /* zero the dead bytes from align to not leak stack to user */
        memset(&raw_data[size - sizeof(u64)], 0, sizeof(u64));
@@ -155,9 +166,5 @@ __kprobes void *perf_trace_buf_prepare(int size, unsigned short type,
        entry->type = type;
 
        return raw_data;
-err:
-       perf_swevent_put_recursion_context(*rctxp);
-err_recursion:
-       return NULL;
 }
 EXPORT_SYMBOL_GPL(perf_trace_buf_prepare);