Re: [PATCH 10/22] tools lib traceevent: Add function plugin

[Namhyung Kim <namhyung@kernel.org>]

2013-11-21 (목), 12:01 +0100, Jiri Olsa:
> Backporting function plugin.
> 
> Backported from Steven Rostedt's trace-cmd repo (HEAD 0f2c2fb):
> git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/trace-cmd.git
> 
> This plugin adds function and parent function fields
> resolving for ftrace:function tracepoint event.
> 
> The diff of 'perf script' output generated by old and new code:
> (data was generated by 'perf record -e ftrace:function ls')
> 
> --- script.function.old
> +++ script.function.new
> -              ls 10781 [001] 32667.291379: ftrace:function:  ffffffff811adb80 <-- ffffffff811afc48
> -              ls 10781 [001] 32667.291379: ftrace:function:  ffffffff811b35d0 <-- ffffffff811adb9b
> -              ls 10781 [001] 32667.291380: ftrace:function:  ffffffff811b3520 <-- ffffffff811b35e8
> -              ls 10781 [001] 32667.291380: ftrace:function:  ffffffff811b2720 <-- ffffffff811b3549
> -              ls 10781 [001] 32667.291381: ftrace:function:  ffffffff81297e10 <-- ffffffff811b356c
> -              ls 10781 [001] 32667.291381: ftrace:function:  ffffffff81298f40 <-- ffffffff81297e2c
> -              ls 10781 [001] 32667.291382: ftrace:function:  ffffffff81076160 <-- ffffffff811afbf0
> -              ls 10781 [001] 32667.291383: ftrace:function:  ffffffff811c3eb0 <-- ffffffff811afbfc
> -              ls 10781 [001] 32667.291383: ftrace:function:  ffffffff8164e100 <-- ffffffff811c3ed8
> -              ls 10781 [001] 32667.291384: ftrace:function:  ffffffff811a5d10 <-- ffffffff811c3f53
> -              ls 10781 [001] 32667.291384: ftrace:function:  ffffffff811e8e70 <-- ffffffff811a5d58
> -              ls 10781 [001] 32667.291385: ftrace:function:  ffffffff811f38e0 <-- ffffffff811a5d63
> -              ls 10781 [001] 32667.291385: ftrace:function:  ffffffff811a9ff0 <-- ffffffff811a5d6b
> -              ls 10781 [001] 32667.291386: ftrace:function:  ffffffff811a9fa0 <-- ffffffff811aa015
> -              ls 10781 [001] 32667.291387: ftrace:function:  ffffffff810851c0 <-- ffffffff811aa053
> -              ls 10781 [001] 32667.291387: ftrace:function:  ffffffff81090e00 <-- ffffffff81085211
> +              ls 10781 [001] 32667.291379: ftrace:function: would_dump <-- setup_new_exec
> +              ls 10781 [001] 32667.291379: ftrace:function:    inode_permission <-- would_dump
> +              ls 10781 [001] 32667.291380: ftrace:function:       __inode_permission <-- inode_permission
> +              ls 10781 [001] 32667.291380: ftrace:function:          generic_permission <-- __inode_permission
> +              ls 10781 [001] 32667.291381: ftrace:function:          security_inode_permission <-- __inode_permission
> +              ls 10781 [001] 32667.291381: ftrace:function:             cap_inode_permission <-- security_inode_permission
> +              ls 10781 [001] 32667.291382: ftrace:function: flush_signal_handlers <-- setup_new_exec
> +              ls 10781 [001] 32667.291383: ftrace:function: do_close_on_exec <-- setup_new_exec
> +              ls 10781 [001] 32667.291383: ftrace:function:    _raw_spin_lock <-- do_close_on_exec
> +              ls 10781 [001] 32667.291384: ftrace:function:    filp_close <-- do_close_on_exec
> +              ls 10781 [001] 32667.291384: ftrace:function:       dnotify_flush <-- filp_close
> +              ls 10781 [001] 32667.291385: ftrace:function:       locks_remove_posix <-- filp_close
> +              ls 10781 [001] 32667.291385: ftrace:function:       fput <-- filp_close
> +              ls 10781 [001] 32667.291386: ftrace:function:          file_sb_list_del <-- fput
> +              ls 10781 [001] 32667.291387: ftrace:function:          task_work_add <-- fput
> +              ls 10781 [001] 32667.291387: ftrace:function:             kick_process <-- task_work_add
> 
> Removing options support as it's not backported yet.
> Currently this plugin supports 2 options:
>  'parent' to display parent function
>  'indent' to show function call indents
> 
> Enabling both of them by default.

[SNIP]
> +static struct func_stack {
> +	int index;

It seems not used anywhere.


> +	int size;
> +	char **stack;
> +} *fstack;
> +
> +static int cpus = -1;
> +
> +#define STK_BLK 10
> +
> +static void add_child(struct func_stack *stack, const char *child, int pos)
> +{
> +	int i;
> +
> +	if (!child)
> +		return;
> +
> +	if (pos < stack->size)
> +		free(stack->stack[pos]);
> +	else {
> +		if (!stack->stack)
> +			stack->stack = malloc_or_die(sizeof(char *) * STK_BLK);

Please do not use this function.


> +		else
> +			stack->stack = realloc(stack->stack, sizeof(char *) *
> +					       (stack->size + STK_BLK));

It seems you need to use a local variable to check return value.


> +		for (i = stack->size; i < stack->size + STK_BLK; i++)
> +			stack->stack[i] = NULL;
> +		stack->size += STK_BLK;
> +	}
> +
> +	stack->stack[pos] = strdup(child);
> +}
> +
> +static int get_index(const char *parent, const char *child, int cpu)

It seems this function does not only to get index but also to add
function stack.  So how about renaming it to something like
add_and_get_index()?

> +{
> +	int i;
> +
> +	if (cpu < 0)
> +		return 0;
> +
> +	if (cpu > cpus) {
> +		if (fstack)
> +			fstack = realloc(fstack, sizeof(*fstack) * (cpu + 1));
> +		else
> +			fstack = malloc_or_die(sizeof(*fstack) * (cpu + 1));

It seems it has same problem as above function.

> +
> +		/* Account for holes in the cpu count */
> +		for (i = cpus + 1; i <= cpu; i++)
> +			memset(&fstack[i], 0, sizeof(fstack[i]));
> +		cpus = cpu;
> +	}
> +
> +	for (i = 0; i < fstack[cpu].size && fstack[cpu].stack[i]; i++) {
> +		if (strcmp(parent, fstack[cpu].stack[i]) == 0) {
> +			add_child(&fstack[cpu], child, i+1);
> +			return i;
> +		}
> +	}
> +
> +	/* Not found */
> +	add_child(&fstack[cpu], parent, 0);
> +	add_child(&fstack[cpu], child, 1);
> +	return 0;
> +}
> +
> +static int function_handler(struct trace_seq *s, struct pevent_record *record,
> +			    struct event_format *event, void *context)
> +{
> +	struct pevent *pevent = event->pevent;
> +	unsigned long long function;
> +	unsigned long long pfunction;
> +	const char *func;
> +	const char *parent;
> +	int i, index;
> +
> +	if (pevent_get_field_val(s, event, "ip", record, &function, 1))
> +		return trace_seq_putc(s, '!');
> +
> +	func = pevent_find_function(pevent, function);
> +
> +	if (pevent_get_field_val(s, event, "parent_ip", record, &pfunction, 1))
> +		return trace_seq_putc(s, '!');
> +
> +	parent = pevent_find_function(pevent, pfunction);
> +
> +	index = get_index(parent, func, record->cpu);
> +
> +	for (i = 0; i < index; i++)
> +		trace_seq_printf(s, "   ");

What about this?

	trace_seq_printf(s, "%*s", index*3, "");

Thanks,
Namhyung

> +
> +	if (func)
> +		trace_seq_printf(s, "%s", func);
> +	else
> +		trace_seq_printf(s, "0x%llx", function);
> +
> +	trace_seq_printf(s, " <-- ");
> +	if (parent)
> +		trace_seq_printf(s, "%s", parent);
> +	else
> +		trace_seq_printf(s, "0x%llx", pfunction);
> +
> +	return 0;
> +}
> +
> +int PEVENT_PLUGIN_LOADER(struct pevent *pevent)
> +{
> +	pevent_register_event_handler(pevent, -1, "ftrace", "function",
> +				      function_handler, NULL);
> +	return 0;
> +}
> +
> +void PEVENT_PLUGIN_UNLOADER(void)
> +{
> +	int i, x;
> +
> +	for (i = 0; i <= cpus; i++) {
> +		for (x = 0; x < fstack[i].size && fstack[i].stack[x]; x++)
> +			free(fstack[i].stack[x]);
> +		free(fstack[i].stack);
> +	}
> +
> +	free(fstack);
> +	fstack = NULL;
> +	cpus = -1;
> +}