diff options
| -rw-r--r-- | Documentation/kernel-parameters.txt | 16 | ||||
| -rw-r--r-- | kernel/trace/trace.c | 54 |
2 files changed, 55 insertions, 15 deletions
diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt index 9776f068306..2b48c52464a 100644 --- a/Documentation/kernel-parameters.txt +++ b/Documentation/kernel-parameters.txt @@ -2859,6 +2859,22 @@ bytes respectively. Such letter suffixes can also be entirely omitted. to facilitate early boot debugging. See also Documentation/trace/events.txt + trace_options=[option-list] + [FTRACE] Enable or disable tracer options at boot. + The option-list is a comma delimited list of options + that can be enabled or disabled just as if you were + to echo the option name into + + /sys/kernel/debug/tracing/trace_options + + For example, to enable stacktrace option (to dump the + stack trace of each event), add to the command line: + + trace_options=stacktrace + + See also Documentation/trace/ftrace.txt "trace options" + section. + transparent_hugepage= [KNL] Format: [always|madvise|never] diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c index 37d1c703e3e..c1434b5ce4d 100644 --- a/kernel/trace/trace.c +++ b/kernel/trace/trace.c @@ -155,6 +155,18 @@ static int __init set_ftrace_dump_on_oops(char *str) } __setup("ftrace_dump_on_oops", set_ftrace_dump_on_oops); + +static char trace_boot_options_buf[MAX_TRACER_SIZE] __initdata; +static char *trace_boot_options __initdata; + +static int __init set_trace_boot_options(char *str) +{ + strncpy(trace_boot_options_buf, str, MAX_TRACER_SIZE); + trace_boot_options = trace_boot_options_buf; + return 0; +} +__setup("trace_options=", set_trace_boot_options); + unsigned long long ns2usecs(cycle_t nsec) { nsec += 500; @@ -2838,24 +2850,14 @@ static void set_tracer_flags(unsigned int mask, int enabled) trace_printk_start_stop_comm(enabled); } -static ssize_t -tracing_trace_options_write(struct file *filp, const char __user *ubuf, - size_t cnt, loff_t *ppos) +static int trace_set_options(char *option) { - char buf[64]; char *cmp; int neg = 0; - int ret; + int ret = 0; int i; - if (cnt >= sizeof(buf)) - return -EINVAL; - - if (copy_from_user(&buf, ubuf, cnt)) - return -EFAULT; - - buf[cnt] = 0; - cmp = strstrip(buf); + cmp = strstrip(option); if (strncmp(cmp, "no", 2) == 0) { neg = 1; @@ -2874,10 +2876,25 @@ tracing_trace_options_write(struct file *filp, const char __user *ubuf, mutex_lock(&trace_types_lock); ret = set_tracer_option(current_trace, cmp, neg); mutex_unlock(&trace_types_lock); - if (ret) - return ret; } + return ret; +} + +static ssize_t +tracing_trace_options_write(struct file *filp, const char __user *ubuf, + size_t cnt, loff_t *ppos) +{ + char buf[64]; + + if (cnt >= sizeof(buf)) + return -EINVAL; + + if (copy_from_user(&buf, ubuf, cnt)) + return -EFAULT; + + trace_set_options(buf); + *ppos += cnt; return cnt; @@ -5133,6 +5150,13 @@ __init static int tracer_alloc_buffers(void) register_die_notifier(&trace_die_notifier); + while (trace_boot_options) { + char *option; + + option = strsep(&trace_boot_options, ","); + trace_set_options(option); + } + return 0; out_free_cpumask: |