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Commit 19063c77 authored by Jason Wessel's avatar Jason Wessel
Browse files

ftrace,kdb: Allow dumping a specific cpu's buffer with ftdump 



In systems with more than one processor it is desirable to look at the
per cpu trace buffers.

Signed-off-by: default avatarJason Wessel <jason.wessel@windriver.com>
Acked-by: default avatarSteven Rostedt <rostedt@goodmis.org>
CC: Frederic Weisbecker <fweisbec@gmail.com>
parent 955b61e5

kernel/trace/trace_kdb.c

+27 −10
Original line number Diff line number Diff line
@@ -17,7 +17,7 @@ 
#include "trace.h"

#include "trace_output.h"



static void ftrace_dump_buf(int skip_lines)

static void ftrace_dump_buf(int skip_lines, long cpu_file)

{

	/* use static because iter can be a bit big for the stack */

	static struct trace_iterator iter;
@@ -44,13 +44,20 @@ static void ftrace_dump_buf(int skip_lines) 
	iter.iter_flags |= TRACE_FILE_LAT_FMT;

	iter.pos = -1;



	if (cpu_file == TRACE_PIPE_ALL_CPU) {

		for_each_tracing_cpu(cpu) {

			iter.buffer_iter[cpu] =

			ring_buffer_read_prepare(iter.tr->buffer, cpu);

			ring_buffer_read_start(iter.buffer_iter[cpu]);

			tracing_iter_reset(&iter, cpu);

		}



	} else {

		iter.cpu_file = cpu_file;

		iter.buffer_iter[cpu_file] =

			ring_buffer_read_prepare(iter.tr->buffer, cpu_file);

		ring_buffer_read_start(iter.buffer_iter[cpu_file]);

		tracing_iter_reset(&iter, cpu_file);

	}

	if (!trace_empty(&iter))

		trace_find_next_entry_inc(&iter);

	while (!trace_empty(&iter)) {
@@ -91,9 +98,10 @@ static void ftrace_dump_buf(int skip_lines) 
static int kdb_ftdump(int argc, const char **argv)

{

	int skip_lines = 0;

	long cpu_file;

	char *cp;



	if (argc > 1)

	if (argc > 2)

		return KDB_ARGCOUNT;



	if (argc) {
@@ -102,8 +110,17 @@ static int kdb_ftdump(int argc, const char **argv) 
			skip_lines = 0;

	}



	if (argc == 2) {

		cpu_file = simple_strtol(argv[2], &cp, 0);

		if (*cp || cpu_file >= NR_CPUS || cpu_file < 0 ||

		    !cpu_online(cpu_file))

			return KDB_BADINT;

	} else {

		cpu_file = TRACE_PIPE_ALL_CPU;

	}



	kdb_trap_printk++;

	ftrace_dump_buf(skip_lines);

	ftrace_dump_buf(skip_lines, cpu_file);

	kdb_trap_printk--;



	return 0;
@@ -111,8 +128,8 @@ static int kdb_ftdump(int argc, const char **argv) 


static __init int kdb_ftrace_register(void)

{

	kdb_register_repeat("ftdump", kdb_ftdump, "", "Dump ftrace log",

			    0, KDB_REPEAT_NONE);

	kdb_register_repeat("ftdump", kdb_ftdump, "[skip_#lines] [cpu]",

			    "Dump ftrace log", 0, KDB_REPEAT_NONE);

	return 0;

}