Re: [PATCH] printk: Add printk_flush() to force buffered text toconsole

From: Steven Rostedt
Date: Fri Jun 22 2012 - 06:45:44 EST


On Fri, 2012-06-22 at 09:17 +0200, Ingo Molnar wrote:

> Maybe also add the actual usage sites, to demonstrate how it's
> going to be used?

Here's the places that I added (and tested) the pr_flush().

I even added 'set_current_task(TASK_UNINTERRUPTIBLE);
schedule_timeout(5*HZ);' to see if it does flush, and it worked fine.

-- Steve

diff --git a/kernel/trace/trace.c b/kernel/trace/trace.c
index 49249c2..f7f2cd0 100644
--- a/kernel/trace/trace.c
+++ b/kernel/trace/trace.c
@@ -825,6 +825,7 @@ int register_tracer(struct tracer *type)

/* the test is responsible for initializing and enabling */
pr_info("Testing tracer %s: ", type->name);
+ pr_flush();
ret = type->selftest(type, tr);
/* the test is responsible for resetting too */
current_trace = saved_tracer;
diff --git a/kernel/trace/trace_events.c b/kernel/trace/trace_events.c
index 29111da..84b674e 100644
--- a/kernel/trace/trace_events.c
+++ b/kernel/trace/trace_events.c
@@ -1606,6 +1606,7 @@ static __init void event_trace_self_tests(void)
#endif

pr_info("Testing event %s: ", call->name);
+ pr_flush();

/*
* If an event is already enabled, someone is using
@@ -1635,6 +1636,7 @@ static __init void event_trace_self_tests(void)
continue;

pr_info("Testing event system %s: ", system->name);
+ pr_flush();

ret = __ftrace_set_clr_event(NULL, system->name, NULL, 1);
if (WARN_ON_ONCE(ret)) {
@@ -1657,6 +1659,7 @@ static __init void event_trace_self_tests(void)

pr_info("Running tests on all trace events:\n");
pr_info("Testing all events: ");
+ pr_flush();

ret = __ftrace_set_clr_event(NULL, NULL, NULL, 1);
if (WARN_ON_ONCE(ret)) {
diff --git a/kernel/trace/trace_selftest.c b/kernel/trace/trace_selftest.c
index 288541f..9638639 100644
--- a/kernel/trace/trace_selftest.c
+++ b/kernel/trace/trace_selftest.c
@@ -161,6 +161,7 @@ static void print_counts(void)
trace_selftest_test_probe3_cnt,
trace_selftest_test_global_cnt,
trace_selftest_test_dyn_cnt);
+ pr_flush();
}

static void reset_counts(void)
@@ -184,6 +185,7 @@ static int trace_selftest_ops(int cnt)

printk(KERN_CONT "PASSED\n");
pr_info("Testing dynamic ftrace ops #%d: ", cnt);
+ pr_flush();

ftrace_enabled = 1;
reset_counts();
@@ -315,6 +317,7 @@ int trace_selftest_startup_dynamic_tracing(struct tracer *trace,
/* The ftrace test PASSED */
printk(KERN_CONT "PASSED\n");
pr_info("Testing dynamic ftrace: ");
+ pr_flush();

/* enable tracing, and record the filter function */
ftrace_enabled = 1;


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