tracing/fastboot: Enable boot tracing only during initcalls

Impact: modify boot tracer

We used to disable the initcall tracing at a specified time (IE: end
of builtin initcalls). But we don't need it anymore. It will be
stopped when initcalls are finished.

However we want two things:

_Start this tracing only after pre-smp initcalls are finished.

_Since we are planning to trace sched_switches at the same time, we
want to enable them only during the initcall execution.

For this purpose, this patch introduce two functions to enable/disable
the sched_switch tracing during boot.

Signed-off-by: Frederic Weisbecker <fweisbec@gmail.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

1 files changed, 3 insertions, 1 deletions

diff --git a/init/main.c b/init/main.c
index 7e117a231af1..4b03cd5656ca 100644
--- a/init/main.c
+++ b/init/main.c
@@ -711,6 +711,7 @@ int do_one_initcall(initcall_t fn)
                 it.caller = task_pid_nr(current);
                 printk("calling  %pF @ %i\n", fn, it.caller);
                 it.calltime = ktime_get();
+                enable_boot_trace();
         }
 
         it.result = fn();
@@ -722,6 +723,7 @@ int do_one_initcall(initcall_t fn)
                 printk("initcall %pF returned %d after %Ld usecs\n", fn,
                         it.result, it.duration);
                 trace_boot(&it, fn);
+                disable_boot_trace();
         }
 
         msgbuf[0] = 0;
@@ -882,7 +884,7 @@ static int __init kernel_init(void * unused)
          * we're essentially up and running. Get rid of the
          * initmem segments and start the user-mode stuff..
          */
-        stop_boot_trace();
+
         init_post();
         return 0;
 }