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tracing/ftrace: add the printk-msg-only option

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Impact: display ftrace_printk messages "as is"

By default, ftrace_printk() messages find their output with some other
informations like pid, caller, ...
Sometimes a developer just want to have the ftrace_printk left "as is", without
other information.

This is done by providing a default-off option called printk-msg-only.
To enable it, just do `echo printk-msg-only > /debugfs/tracing/trace_options`

Before the patch:

           <...>-2739  [000]   145.692153: __might_sleep: I'm an ftrace_printk msg in __might_sleep
           <...>-2739  [000]   145.692155: __might_sleep: I'm another ftrace_printk msg in __might_sleep

After the patch and the printk-msg-only option enabled:

I'm an ftrace_printk msg in __might_sleep
I'm another ftrace_printk msg in __might_sleep

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
This commit is contained in:
Frederic Weisbecker 2008-12-13 20:18:13 +01:00 committed by Ingo Molnar
parent 2c2d7329d8
commit 66896a85cf
2 changed files with 27 additions and 1 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

25
kernel/trace/trace.c
View File

@ -287,6 +287,7 @@ static const char *trace_options[] = {
"annotate",
"userstacktrace",
"sym-userobj",
"printk-msg-only",
NULL
};
@ -2265,6 +2266,25 @@ static enum print_line_t print_hex_fmt(struct trace_iterator *iter)
return TRACE_TYPE_HANDLED;
}
static enum print_line_t print_printk_msg_only(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
struct trace_entry *entry = iter->ent;
struct print_entry *field;
int ret;
trace_assign_type(field, entry);
ret = trace_seq_printf(s, field->buf);
if (!ret)
return TRACE_TYPE_PARTIAL_LINE;
if (entry->flags & TRACE_FLAG_CONT)
trace_seq_print_cont(s, iter);
return TRACE_TYPE_HANDLED;
}
static enum print_line_t print_bin_fmt(struct trace_iterator *iter)
{
struct trace_seq *s = &iter->seq;
@ -2345,6 +2365,11 @@ static enum print_line_t print_trace_line(struct trace_iterator *iter)
return ret;
}
if (iter->ent->type == TRACE_PRINT &&
trace_flags & TRACE_ITER_PRINTK &&
trace_flags & TRACE_ITER_PRINTK_MSGONLY)
return print_printk_msg_only(iter);
if (trace_flags & TRACE_ITER_BIN)
return print_bin_fmt(iter);

3
kernel/trace/trace.h
View File

@ -578,7 +578,8 @@ enum trace_iterator_flags {
TRACE_ITER_BRANCH = 0x1000,
TRACE_ITER_ANNOTATE = 0x2000,
TRACE_ITER_USERSTACKTRACE = 0x4000,
TRACE_ITER_SYM_USEROBJ = 0x8000
TRACE_ITER_SYM_USEROBJ = 0x8000,
TRACE_ITER_PRINTK_MSGONLY = 0x10000
};
/*