tracing: Simplify print_graph_cpu()
[safe/jmp/linux-2.6] / kernel / trace / trace_functions_graph.c
index 88f8d9d..e30472d 100644 (file)
 #include "trace.h"
 #include "trace_output.h"
 
+struct fgraph_data {
+       pid_t           last_pid;
+       int             depth;
+};
+
 #define TRACE_GRAPH_INDENT     2
 
 /* Flag options */
@@ -50,6 +55,117 @@ static struct tracer_flags tracer_flags = {
 /* pid on the last trace processed */
 
 
+/* Add a function return address to the trace stack on thread info.*/
+int
+ftrace_push_return_trace(unsigned long ret, unsigned long func, int *depth,
+                        unsigned long frame_pointer)
+{
+       unsigned long long calltime;
+       int index;
+
+       if (!current->ret_stack)
+               return -EBUSY;
+
+       /*
+        * We must make sure the ret_stack is tested before we read
+        * anything else.
+        */
+       smp_rmb();
+
+       /* The return trace stack is full */
+       if (current->curr_ret_stack == FTRACE_RETFUNC_DEPTH - 1) {
+               atomic_inc(&current->trace_overrun);
+               return -EBUSY;
+       }
+
+       calltime = trace_clock_local();
+
+       index = ++current->curr_ret_stack;
+       barrier();
+       current->ret_stack[index].ret = ret;
+       current->ret_stack[index].func = func;
+       current->ret_stack[index].calltime = calltime;
+       current->ret_stack[index].subtime = 0;
+       current->ret_stack[index].fp = frame_pointer;
+       *depth = index;
+
+       return 0;
+}
+
+/* Retrieve a function return address to the trace stack on thread info.*/
+static void
+ftrace_pop_return_trace(struct ftrace_graph_ret *trace, unsigned long *ret,
+                       unsigned long frame_pointer)
+{
+       int index;
+
+       index = current->curr_ret_stack;
+
+       if (unlikely(index < 0)) {
+               ftrace_graph_stop();
+               WARN_ON(1);
+               /* Might as well panic, otherwise we have no where to go */
+               *ret = (unsigned long)panic;
+               return;
+       }
+
+#ifdef CONFIG_HAVE_FUNCTION_GRAPH_FP_TEST
+       /*
+        * The arch may choose to record the frame pointer used
+        * and check it here to make sure that it is what we expect it
+        * to be. If gcc does not set the place holder of the return
+        * address in the frame pointer, and does a copy instead, then
+        * the function graph trace will fail. This test detects this
+        * case.
+        *
+        * Currently, x86_32 with optimize for size (-Os) makes the latest
+        * gcc do the above.
+        */
+       if (unlikely(current->ret_stack[index].fp != frame_pointer)) {
+               ftrace_graph_stop();
+               WARN(1, "Bad frame pointer: expected %lx, received %lx\n"
+                    "  from func %pF return to %lx\n",
+                    current->ret_stack[index].fp,
+                    frame_pointer,
+                    (void *)current->ret_stack[index].func,
+                    current->ret_stack[index].ret);
+               *ret = (unsigned long)panic;
+               return;
+       }
+#endif
+
+       *ret = current->ret_stack[index].ret;
+       trace->func = current->ret_stack[index].func;
+       trace->calltime = current->ret_stack[index].calltime;
+       trace->overrun = atomic_read(&current->trace_overrun);
+       trace->depth = index;
+}
+
+/*
+ * Send the trace to the ring-buffer.
+ * @return the original return address.
+ */
+unsigned long ftrace_return_to_handler(unsigned long frame_pointer)
+{
+       struct ftrace_graph_ret trace;
+       unsigned long ret;
+
+       ftrace_pop_return_trace(&trace, &ret, frame_pointer);
+       trace.rettime = trace_clock_local();
+       ftrace_graph_return(&trace);
+       barrier();
+       current->curr_ret_stack--;
+
+       if (unlikely(!ret)) {
+               ftrace_graph_stop();
+               WARN_ON(1);
+               /* Might as well panic. What else to do? */
+               ret = (unsigned long)panic;
+       }
+
+       return ret;
+}
+
 static int graph_trace_init(struct trace_array *tr)
 {
        int ret = register_ftrace_graph(&trace_graph_return,
@@ -67,43 +183,19 @@ static void graph_trace_reset(struct trace_array *tr)
        unregister_ftrace_graph();
 }
 
-static inline int log10_cpu(int nb)
-{
-       if (nb / 100)
-               return 3;
-       if (nb / 10)
-               return 2;
-       return 1;
-}
+static int max_bytes_for_cpu;
 
 static enum print_line_t
 print_graph_cpu(struct trace_seq *s, int cpu)
 {
-       int i;
        int ret;
-       int log10_this = log10_cpu(cpu);
-       int log10_all = log10_cpu(cpumask_weight(cpu_online_mask));
-
 
        /*
         * Start with a space character - to make it stand out
         * to the right a bit when trace output is pasted into
         * email:
         */
-       ret = trace_seq_printf(s, " ");
-
-       /*
-        * Tricky - we space the CPU field according to the max
-        * number of online CPUs. On a 2-cpu system it would take
-        * a maximum of 1 digit - on a 128 cpu system it would
-        * take up to 3 digits:
-        */
-       for (i = 0; i < log10_all - log10_this; i++) {
-               ret = trace_seq_printf(s, " ");
-               if (!ret)
-                       return TRACE_TYPE_PARTIAL_LINE;
-       }
-       ret = trace_seq_printf(s, "%d) ", cpu);
+       ret = trace_seq_printf(s, " %*d) ", max_bytes_for_cpu, cpu);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
@@ -115,15 +207,15 @@ print_graph_cpu(struct trace_seq *s, int cpu)
 static enum print_line_t
 print_graph_proc(struct trace_seq *s, pid_t pid)
 {
-       int i;
-       int ret;
-       int len;
-       char comm[8];
-       int spaces = 0;
+       char comm[TASK_COMM_LEN];
        /* sign + log10(MAX_INT) + '\0' */
        char pid_str[11];
+       int spaces = 0;
+       int ret;
+       int len;
+       int i;
 
-       strncpy(comm, trace_find_cmdline(pid), 7);
+       trace_find_cmdline(pid, comm);
        comm[7] = '\0';
        sprintf(pid_str, "%d", pid);
 
@@ -156,16 +248,16 @@ print_graph_proc(struct trace_seq *s, pid_t pid)
 
 /* If the pid changed since the last trace, output this event */
 static enum print_line_t
-verif_pid(struct trace_seq *s, pid_t pid, int cpu, pid_t *last_pids_cpu)
+verif_pid(struct trace_seq *s, pid_t pid, int cpu, struct fgraph_data *data)
 {
        pid_t prev_pid;
        pid_t *last_pid;
        int ret;
 
-       if (!last_pids_cpu)
+       if (!data)
                return TRACE_TYPE_HANDLED;
 
-       last_pid = per_cpu_ptr(last_pids_cpu, cpu);
+       last_pid = &(per_cpu_ptr(data, cpu)->last_pid);
 
        if (*last_pid == pid)
                return TRACE_TYPE_HANDLED;
@@ -186,34 +278,34 @@ verif_pid(struct trace_seq *s, pid_t pid, int cpu, pid_t *last_pids_cpu)
        ret = trace_seq_printf(s,
                " ------------------------------------------\n");
        if (!ret)
-               TRACE_TYPE_PARTIAL_LINE;
+               return TRACE_TYPE_PARTIAL_LINE;
 
        ret = print_graph_cpu(s, cpu);
        if (ret == TRACE_TYPE_PARTIAL_LINE)
-               TRACE_TYPE_PARTIAL_LINE;
+               return TRACE_TYPE_PARTIAL_LINE;
 
        ret = print_graph_proc(s, prev_pid);
        if (ret == TRACE_TYPE_PARTIAL_LINE)
-               TRACE_TYPE_PARTIAL_LINE;
+               return TRACE_TYPE_PARTIAL_LINE;
 
        ret = trace_seq_printf(s, " => ");
        if (!ret)
-               TRACE_TYPE_PARTIAL_LINE;
+               return TRACE_TYPE_PARTIAL_LINE;
 
        ret = print_graph_proc(s, pid);
        if (ret == TRACE_TYPE_PARTIAL_LINE)
-               TRACE_TYPE_PARTIAL_LINE;
+               return TRACE_TYPE_PARTIAL_LINE;
 
        ret = trace_seq_printf(s,
                "\n ------------------------------------------\n\n");
        if (!ret)
-               TRACE_TYPE_PARTIAL_LINE;
+               return TRACE_TYPE_PARTIAL_LINE;
 
-       return ret;
+       return TRACE_TYPE_HANDLED;
 }
 
-static bool
-trace_branch_is_leaf(struct trace_iterator *iter,
+static struct ftrace_graph_ret_entry *
+get_return_for_leaf(struct trace_iterator *iter,
                struct ftrace_graph_ent_entry *curr)
 {
        struct ring_buffer_iter *ring_iter;
@@ -222,24 +314,33 @@ trace_branch_is_leaf(struct trace_iterator *iter,
 
        ring_iter = iter->buffer_iter[iter->cpu];
 
-       if (!ring_iter)
-               return false;
-
-       event = ring_buffer_iter_peek(ring_iter, NULL);
+       /* First peek to compare current entry and the next one */
+       if (ring_iter)
+               event = ring_buffer_iter_peek(ring_iter, NULL);
+       else {
+       /* We need to consume the current entry to see the next one */
+               ring_buffer_consume(iter->tr->buffer, iter->cpu, NULL);
+               event = ring_buffer_peek(iter->tr->buffer, iter->cpu,
+                                       NULL);
+       }
 
        if (!event)
-               return false;
+               return NULL;
 
        next = ring_buffer_event_data(event);
 
        if (next->ent.type != TRACE_GRAPH_RET)
-               return false;
+               return NULL;
 
        if (curr->ent.pid != next->ent.pid ||
                        curr->graph_ent.func != next->ret.func)
-               return false;
+               return NULL;
+
+       /* this is a leaf, now advance the iterator */
+       if (ring_iter)
+               ring_buffer_read(ring_iter, NULL);
 
-       return true;
+       return next;
 }
 
 /* Signal a overhead of time execution to the output */
@@ -267,16 +368,35 @@ print_graph_overhead(unsigned long long duration, struct trace_seq *s)
        return trace_seq_printf(s, "  ");
 }
 
+static int print_graph_abs_time(u64 t, struct trace_seq *s)
+{
+       unsigned long usecs_rem;
+
+       usecs_rem = do_div(t, NSEC_PER_SEC);
+       usecs_rem /= 1000;
+
+       return trace_seq_printf(s, "%5lu.%06lu |  ",
+                       (unsigned long)t, usecs_rem);
+}
+
 static enum print_line_t
-print_graph_irq(struct trace_seq *s, unsigned long addr,
+print_graph_irq(struct trace_iterator *iter, unsigned long addr,
                enum trace_type type, int cpu, pid_t pid)
 {
        int ret;
+       struct trace_seq *s = &iter->seq;
 
        if (addr < (unsigned long)__irqentry_text_start ||
                addr >= (unsigned long)__irqentry_text_end)
                return TRACE_TYPE_UNHANDLED;
 
+       /* Absolute time */
+       if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
+               ret = print_graph_abs_time(iter->ts, s);
+               if (!ret)
+                       return TRACE_TYPE_PARTIAL_LINE;
+       }
+
        /* Cpu */
        if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
                ret = print_graph_cpu(s, cpu);
@@ -316,8 +436,8 @@ print_graph_irq(struct trace_seq *s, unsigned long addr,
        return TRACE_TYPE_HANDLED;
 }
 
-static enum print_line_t
-print_graph_duration(unsigned long long duration, struct trace_seq *s)
+enum print_line_t
+trace_print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
        unsigned long nsecs_rem = do_div(duration, 1000);
        /* log10(ULONG_MAX) + '\0' */
@@ -354,44 +474,54 @@ print_graph_duration(unsigned long long duration, struct trace_seq *s)
                if (!ret)
                        return TRACE_TYPE_PARTIAL_LINE;
        }
-
-       ret = trace_seq_printf(s, "|  ");
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
        return TRACE_TYPE_HANDLED;
-
 }
 
-static int print_graph_abs_time(u64 t, struct trace_seq *s)
+static enum print_line_t
+print_graph_duration(unsigned long long duration, struct trace_seq *s)
 {
-       unsigned long usecs_rem;
+       int ret;
 
-       usecs_rem = do_div(t, 1000000000);
-       usecs_rem /= 1000;
+       ret = trace_print_graph_duration(duration, s);
+       if (ret != TRACE_TYPE_HANDLED)
+               return ret;
 
-       return trace_seq_printf(s, "%5lu.%06lu |  ",
-                       (unsigned long)t, usecs_rem);
+       ret = trace_seq_printf(s, "|  ");
+       if (!ret)
+               return TRACE_TYPE_PARTIAL_LINE;
+
+       return TRACE_TYPE_HANDLED;
 }
 
 /* Case of a leaf function on its call entry */
 static enum print_line_t
 print_graph_entry_leaf(struct trace_iterator *iter,
-               struct ftrace_graph_ent_entry *entry, struct trace_seq *s)
+               struct ftrace_graph_ent_entry *entry,
+               struct ftrace_graph_ret_entry *ret_entry, struct trace_seq *s)
 {
-       struct ftrace_graph_ret_entry *ret_entry;
+       struct fgraph_data *data = iter->private;
        struct ftrace_graph_ret *graph_ret;
-       struct ring_buffer_event *event;
        struct ftrace_graph_ent *call;
        unsigned long long duration;
        int ret;
        int i;
 
-       event = ring_buffer_read(iter->buffer_iter[iter->cpu], NULL);
-       ret_entry = ring_buffer_event_data(event);
        graph_ret = &ret_entry->ret;
        call = &entry->graph_ent;
        duration = graph_ret->rettime - graph_ret->calltime;
 
+       if (data) {
+               int cpu = iter->cpu;
+               int *depth = &(per_cpu_ptr(data, cpu)->depth);
+
+               /*
+                * Comments display at + 1 to depth. Since
+                * this is a leaf function, keep the comments
+                * equal to this depth.
+                */
+               *depth = call->depth - 1;
+       }
+
        /* Overhead */
        ret = print_graph_overhead(duration, s);
        if (!ret)
@@ -411,11 +541,7 @@ print_graph_entry_leaf(struct trace_iterator *iter,
                        return TRACE_TYPE_PARTIAL_LINE;
        }
 
-       ret = seq_print_ip_sym(s, call->func, 0);
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
-
-       ret = trace_seq_printf(s, "();\n");
+       ret = trace_seq_printf(s, "%pf();\n", (void *)call->func);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
@@ -423,12 +549,21 @@ print_graph_entry_leaf(struct trace_iterator *iter,
 }
 
 static enum print_line_t
-print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
-                       struct trace_seq *s, pid_t pid, int cpu)
+print_graph_entry_nested(struct trace_iterator *iter,
+                        struct ftrace_graph_ent_entry *entry,
+                        struct trace_seq *s, int cpu)
 {
-       int i;
-       int ret;
        struct ftrace_graph_ent *call = &entry->graph_ent;
+       struct fgraph_data *data = iter->private;
+       int ret;
+       int i;
+
+       if (data) {
+               int cpu = iter->cpu;
+               int *depth = &(per_cpu_ptr(data, cpu)->depth);
+
+               *depth = call->depth;
+       }
 
        /* No overhead */
        ret = print_graph_overhead(-1, s);
@@ -449,35 +584,36 @@ print_graph_entry_nested(struct ftrace_graph_ent_entry *entry,
                        return TRACE_TYPE_PARTIAL_LINE;
        }
 
-       ret = seq_print_ip_sym(s, call->func, 0);
-       if (!ret)
-               return TRACE_TYPE_PARTIAL_LINE;
-
-       ret = trace_seq_printf(s, "() {\n");
+       ret = trace_seq_printf(s, "%pf() {\n", (void *)call->func);
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
-       return TRACE_TYPE_HANDLED;
+       /*
+        * we already consumed the current entry to check the next one
+        * and see if this is a leaf.
+        */
+       return TRACE_TYPE_NO_CONSUME;
 }
 
 static enum print_line_t
-print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
-                       struct trace_iterator *iter)
+print_graph_prologue(struct trace_iterator *iter, struct trace_seq *s,
+                    int type, unsigned long addr)
 {
-       int ret;
-       int cpu = iter->cpu;
-       pid_t *last_entry = iter->private;
+       struct fgraph_data *data = iter->private;
        struct trace_entry *ent = iter->ent;
-       struct ftrace_graph_ent *call = &field->graph_ent;
+       int cpu = iter->cpu;
+       int ret;
 
        /* Pid */
-       if (verif_pid(s, ent->pid, cpu, last_entry) == TRACE_TYPE_PARTIAL_LINE)
+       if (verif_pid(s, ent->pid, cpu, data) == TRACE_TYPE_PARTIAL_LINE)
                return TRACE_TYPE_PARTIAL_LINE;
 
-       /* Interrupt */
-       ret = print_graph_irq(s, call->func, TRACE_GRAPH_ENT, cpu, ent->pid);
-       if (ret == TRACE_TYPE_PARTIAL_LINE)
-               return TRACE_TYPE_PARTIAL_LINE;
+       if (type) {
+               /* Interrupt */
+               ret = print_graph_irq(iter, addr, type, cpu, ent->pid);
+               if (ret == TRACE_TYPE_PARTIAL_LINE)
+                       return TRACE_TYPE_PARTIAL_LINE;
+       }
 
        /* Absolute time */
        if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
@@ -504,10 +640,25 @@ print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
                        return TRACE_TYPE_PARTIAL_LINE;
        }
 
-       if (trace_branch_is_leaf(iter, field))
-               return print_graph_entry_leaf(iter, field, s);
+       return 0;
+}
+
+static enum print_line_t
+print_graph_entry(struct ftrace_graph_ent_entry *field, struct trace_seq *s,
+                       struct trace_iterator *iter)
+{
+       int cpu = iter->cpu;
+       struct ftrace_graph_ent *call = &field->graph_ent;
+       struct ftrace_graph_ret_entry *leaf_ret;
+
+       if (print_graph_prologue(iter, s, TRACE_GRAPH_ENT, call->func))
+               return TRACE_TYPE_PARTIAL_LINE;
+
+       leaf_ret = get_return_for_leaf(iter, field);
+       if (leaf_ret)
+               return print_graph_entry_leaf(iter, field, leaf_ret, s);
        else
-               return print_graph_entry_nested(field, s, iter->ent->pid, cpu);
+               return print_graph_entry_nested(iter, field, s, cpu);
 
 }
 
@@ -515,40 +666,27 @@ static enum print_line_t
 print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
                   struct trace_entry *ent, struct trace_iterator *iter)
 {
-       int i;
-       int ret;
-       int cpu = iter->cpu;
-       pid_t *last_pid = iter->private;
        unsigned long long duration = trace->rettime - trace->calltime;
+       struct fgraph_data *data = iter->private;
+       pid_t pid = ent->pid;
+       int cpu = iter->cpu;
+       int ret;
+       int i;
 
-       /* Pid */
-       if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)
-               return TRACE_TYPE_PARTIAL_LINE;
-
-       /* Absolute time */
-       if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
-               ret = print_graph_abs_time(iter->ts, s);
-               if (!ret)
-                       return TRACE_TYPE_PARTIAL_LINE;
-       }
+       if (data) {
+               int cpu = iter->cpu;
+               int *depth = &(per_cpu_ptr(data, cpu)->depth);
 
-       /* Cpu */
-       if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
-               ret = print_graph_cpu(s, cpu);
-               if (ret == TRACE_TYPE_PARTIAL_LINE)
-                       return TRACE_TYPE_PARTIAL_LINE;
+               /*
+                * Comments display at + 1 to depth. This is the
+                * return from a function, we now want the comments
+                * to display at the same level of the bracket.
+                */
+               *depth = trace->depth - 1;
        }
 
-       /* Proc */
-       if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
-               ret = print_graph_proc(s, ent->pid);
-               if (ret == TRACE_TYPE_PARTIAL_LINE)
-                       return TRACE_TYPE_PARTIAL_LINE;
-
-               ret = trace_seq_printf(s, " | ");
-               if (!ret)
-                       return TRACE_TYPE_PARTIAL_LINE;
-       }
+       if (print_graph_prologue(iter, s, 0, 0))
+               return TRACE_TYPE_PARTIAL_LINE;
 
        /* Overhead */
        ret = print_graph_overhead(duration, s);
@@ -581,7 +719,7 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
                        return TRACE_TYPE_PARTIAL_LINE;
        }
 
-       ret = print_graph_irq(s, trace->func, TRACE_GRAPH_RET, cpu, ent->pid);
+       ret = print_graph_irq(iter, trace->func, TRACE_GRAPH_RET, cpu, pid);
        if (ret == TRACE_TYPE_PARTIAL_LINE)
                return TRACE_TYPE_PARTIAL_LINE;
 
@@ -589,43 +727,22 @@ print_graph_return(struct ftrace_graph_ret *trace, struct trace_seq *s,
 }
 
 static enum print_line_t
-print_graph_comment(struct print_entry *trace, struct trace_seq *s,
-                  struct trace_entry *ent, struct trace_iterator *iter)
+print_graph_comment(struct trace_seq *s,  struct trace_entry *ent,
+                   struct trace_iterator *iter)
 {
-       int i;
+       unsigned long sym_flags = (trace_flags & TRACE_ITER_SYM_MASK);
+       struct fgraph_data *data = iter->private;
+       struct trace_event *event;
+       int depth = 0;
        int ret;
-       int cpu = iter->cpu;
-       pid_t *last_pid = iter->private;
+       int i;
 
-       /* Absolute time */
-       if (tracer_flags.val & TRACE_GRAPH_PRINT_ABS_TIME) {
-               ret = print_graph_abs_time(iter->ts, s);
-               if (!ret)
-                       return TRACE_TYPE_PARTIAL_LINE;
-       }
+       if (data)
+               depth = per_cpu_ptr(data, iter->cpu)->depth;
 
-       /* Pid */
-       if (verif_pid(s, ent->pid, cpu, last_pid) == TRACE_TYPE_PARTIAL_LINE)
+       if (print_graph_prologue(iter, s, 0, 0))
                return TRACE_TYPE_PARTIAL_LINE;
 
-       /* Cpu */
-       if (tracer_flags.val & TRACE_GRAPH_PRINT_CPU) {
-               ret = print_graph_cpu(s, cpu);
-               if (ret == TRACE_TYPE_PARTIAL_LINE)
-                       return TRACE_TYPE_PARTIAL_LINE;
-       }
-
-       /* Proc */
-       if (tracer_flags.val & TRACE_GRAPH_PRINT_PROC) {
-               ret = print_graph_proc(s, ent->pid);
-               if (ret == TRACE_TYPE_PARTIAL_LINE)
-                       return TRACE_TYPE_PARTIAL_LINE;
-
-               ret = trace_seq_printf(s, " | ");
-               if (!ret)
-                       return TRACE_TYPE_PARTIAL_LINE;
-       }
-
        /* No overhead */
        ret = print_graph_overhead(-1, s);
        if (!ret)
@@ -639,18 +756,39 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s,
        }
 
        /* Indentation */
-       if (trace->depth > 0)
-               for (i = 0; i < (trace->depth + 1) * TRACE_GRAPH_INDENT; i++) {
+       if (depth > 0)
+               for (i = 0; i < (depth + 1) * TRACE_GRAPH_INDENT; i++) {
                        ret = trace_seq_printf(s, " ");
                        if (!ret)
                                return TRACE_TYPE_PARTIAL_LINE;
                }
 
        /* The comment */
-       ret = trace_seq_printf(s, "/* %s", trace->buf);
+       ret = trace_seq_printf(s, "/* ");
        if (!ret)
                return TRACE_TYPE_PARTIAL_LINE;
 
+       switch (iter->ent->type) {
+       case TRACE_BPRINT:
+               ret = trace_print_bprintk_msg_only(iter);
+               if (ret != TRACE_TYPE_HANDLED)
+                       return ret;
+               break;
+       case TRACE_PRINT:
+               ret = trace_print_printk_msg_only(iter);
+               if (ret != TRACE_TYPE_HANDLED)
+                       return ret;
+               break;
+       default:
+               event = ftrace_find_event(ent->type);
+               if (!event)
+                       return TRACE_TYPE_UNHANDLED;
+
+               ret = event->trace(iter, sym_flags);
+               if (ret != TRACE_TYPE_HANDLED)
+                       return ret;
+       }
+
        /* Strip ending newline */
        if (s->buffer[s->len - 1] == '\n') {
                s->buffer[s->len - 1] = '\0';
@@ -668,8 +806,8 @@ print_graph_comment(struct print_entry *trace, struct trace_seq *s,
 enum print_line_t
 print_graph_function(struct trace_iterator *iter)
 {
-       struct trace_seq *s = &iter->seq;
        struct trace_entry *entry = iter->ent;
+       struct trace_seq *s = &iter->seq;
 
        switch (entry->type) {
        case TRACE_GRAPH_ENT: {
@@ -682,14 +820,11 @@ print_graph_function(struct trace_iterator *iter)
                trace_assign_type(field, entry);
                return print_graph_return(&field->ret, s, entry, iter);
        }
-       case TRACE_PRINT: {
-               struct print_entry *field;
-               trace_assign_type(field, entry);
-               return print_graph_comment(field, s, entry, iter);
-       }
        default:
-               return TRACE_TYPE_UNHANDLED;
+               return print_graph_comment(s, entry, iter);
        }
+
+       return TRACE_TYPE_HANDLED;
 }
 
 static void print_graph_headers(struct seq_file *s)
@@ -721,32 +856,35 @@ static void print_graph_headers(struct seq_file *s)
 
 static void graph_trace_open(struct trace_iterator *iter)
 {
-       /* pid on the last trace processed */
-       pid_t *last_pid = alloc_percpu(pid_t);
+       /* pid and depth on the last trace processed */
+       struct fgraph_data *data = alloc_percpu(struct fgraph_data);
        int cpu;
 
-       if (!last_pid)
+       if (!data)
                pr_warning("function graph tracer: not enough memory\n");
        else
                for_each_possible_cpu(cpu) {
-                       pid_t *pid = per_cpu_ptr(last_pid, cpu);
+                       pid_t *pid = &(per_cpu_ptr(data, cpu)->last_pid);
+                       int *depth = &(per_cpu_ptr(data, cpu)->depth);
                        *pid = -1;
+                       *depth = 0;
                }
 
-       iter->private = last_pid;
+       iter->private = data;
 }
 
 static void graph_trace_close(struct trace_iterator *iter)
 {
-       percpu_free(iter->private);
+       free_percpu(iter->private);
 }
 
 static struct tracer graph_trace __read_mostly = {
-       .name           = "function_graph",
+       .name           = "function_graph",
        .open           = graph_trace_open,
        .close          = graph_trace_close,
-       .init           = graph_trace_init,
-       .reset          = graph_trace_reset,
+       .wait_pipe      = poll_wait_pipe,
+       .init           = graph_trace_init,
+       .reset          = graph_trace_reset,
        .print_line     = print_graph_function,
        .print_header   = print_graph_headers,
        .flags          = &tracer_flags,
@@ -757,6 +895,8 @@ static struct tracer graph_trace __read_mostly = {
 
 static __init int init_graph_trace(void)
 {
+       max_bytes_for_cpu = snprintf(NULL, 0, "%d", nr_cpu_ids - 1);
+
        return register_tracer(&graph_trace);
 }