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Commit 568b329a authored by Alexei Starovoitov's avatar Alexei Starovoitov Committed by David S. Miller
Browse files

perf: generalize perf_callchain 



. avoid walking the stack when there is no room left in the buffer
. generalize get_perf_callchain() to be called from bpf helper

Signed-off-by: default avatarAlexei Starovoitov <ast@kernel.org>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6b83d28a

arch/x86/include/asm/stacktrace.h

+1 −1
Original line number Original line Diff line number Diff line
@@ -37,7 +37,7 @@ print_context_stack_bp(struct thread_info *tinfo, 
/* Generic stack tracer with callbacks */

/* Generic stack tracer with callbacks */





struct stacktrace_ops {

struct stacktrace_ops {

	void (*address)(void *data, unsigned long address, int reliable);

	int (*address)(void *data, unsigned long address, int reliable);

	/* On negative return stop dumping */

	/* On negative return stop dumping */

	int (*stack)(void *data, char *name);

	int (*stack)(void *data, char *name);

	walk_stack_t	walk_stack;

	walk_stack_t	walk_stack;

arch/x86/kernel/cpu/perf_event.c

+2 −2
Original line number Original line Diff line number Diff line
@@ -2180,11 +2180,11 @@ static int backtrace_stack(void *data, char *name) 
	return 0;

	return 0;

}

}





static void backtrace_address(void *data, unsigned long addr, int reliable)

static int backtrace_address(void *data, unsigned long addr, int reliable)

{

{

	struct perf_callchain_entry *entry = data;

	struct perf_callchain_entry *entry = data;





	perf_callchain_store(entry, addr);

	return perf_callchain_store(entry, addr);

}

}





static const struct stacktrace_ops backtrace_ops = {

static const struct stacktrace_ops backtrace_ops = {

arch/x86/kernel/dumpstack.c

+4 −2
Original line number Original line Diff line number Diff line
@@ -135,7 +135,8 @@ print_context_stack_bp(struct thread_info *tinfo, 
		if (!__kernel_text_address(addr))

		if (!__kernel_text_address(addr))

			break;

			break;





		ops->address(data, addr, 1);

		if (ops->address(data, addr, 1))

			break;

		frame = frame->next_frame;

		frame = frame->next_frame;

		ret_addr = &frame->return_address;

		ret_addr = &frame->return_address;

		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);

		print_ftrace_graph_addr(addr, data, ops, tinfo, graph);
@@ -154,10 +155,11 @@ static int print_trace_stack(void *data, char *name) 
/*

/*

 * Print one address/symbol entries per line.

 * Print one address/symbol entries per line.

 */

 */

static void print_trace_address(void *data, unsigned long addr, int reliable)

static int print_trace_address(void *data, unsigned long addr, int reliable)

{

{

	touch_nmi_watchdog();

	touch_nmi_watchdog();

	printk_stack_address(addr, reliable, data);

	printk_stack_address(addr, reliable, data);

	return 0;

}

}





static const struct stacktrace_ops print_trace_ops = {

static const struct stacktrace_ops print_trace_ops = {

arch/x86/kernel/stacktrace.c

+11 −7
Original line number Original line Diff line number Diff line
@@ -14,30 +14,34 @@ static int save_stack_stack(void *data, char *name) 
	return 0;

	return 0;

}

}





static void

static int

__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)

__save_stack_address(void *data, unsigned long addr, bool reliable, bool nosched)

{

{

	struct stack_trace *trace = data;

	struct stack_trace *trace = data;

#ifdef CONFIG_FRAME_POINTER

#ifdef CONFIG_FRAME_POINTER

	if (!reliable)

	if (!reliable)

		return;

		return 0;

#endif

#endif

	if (nosched && in_sched_functions(addr))

	if (nosched && in_sched_functions(addr))

		return;

		return 0;

	if (trace->skip > 0) {

	if (trace->skip > 0) {

		trace->skip--;

		trace->skip--;

		return;

		return 0;

	}

	}

	if (trace->nr_entries < trace->max_entries)

	if (trace->nr_entries < trace->max_entries) {

		trace->entries[trace->nr_entries++] = addr;

		trace->entries[trace->nr_entries++] = addr;

		return 0;

	} else {

		return -1; /* no more room, stop walking the stack */

	}

}

}





static void save_stack_address(void *data, unsigned long addr, int reliable)

static int save_stack_address(void *data, unsigned long addr, int reliable)

{

{

	return __save_stack_address(data, addr, reliable, false);

	return __save_stack_address(data, addr, reliable, false);

}

}





static void

static int

save_stack_address_nosched(void *data, unsigned long addr, int reliable)

save_stack_address_nosched(void *data, unsigned long addr, int reliable)

{

{

	return __save_stack_address(data, addr, reliable, true);

	return __save_stack_address(data, addr, reliable, true);

arch/x86/oprofile/backtrace.c

+2 −1
Original line number Original line Diff line number Diff line
@@ -23,12 +23,13 @@ static int backtrace_stack(void *data, char *name) 
	return 0;

	return 0;

}

}





static void backtrace_address(void *data, unsigned long addr, int reliable)

static int backtrace_address(void *data, unsigned long addr, int reliable)

{

{

	unsigned int *depth = data;

	unsigned int *depth = data;





	if ((*depth)--)

	if ((*depth)--)

		oprofile_add_trace(addr);

		oprofile_add_trace(addr);

	return 0;

}

}





static struct stacktrace_ops backtrace_ops = {

static struct stacktrace_ops backtrace_ops = {