[lkml]   [2012]   [Aug]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
Messages in this thread
SubjectRe: [RFC PATCH 1/1] trace: Move trace event enable from fs_initcall to early_initcall
On Fri, Aug 17, 2012 at 10:55 AM, Steven Rostedt <> wrote:
> On Fri, 2012-08-17 at 08:01 -0300, Ezequiel Garcia wrote:
>> Regarding the 'complete solution': to be able to capture events from
>> the very beggining...
>> Have you thought about this?
>> Could you give me a hint on how could I implement it?
> How far in the "beginning"? Before memory is set up?


> I wouldn't do that.

Yeah, perhaps it sounds crazy. It makes some sense for kmem events, though.

> I have in the past (set up before memory was finished being
> initialized), but things have changed since then.
> One thing that we could do for those that want really early tracing, is
> to add a config option to add a static temporary ring buffer, that gets

Yes, something like this would be ideal. How would this ring buffer be
Perhaps as static and __initdata?
This way it would be released afterwards, right?

> copied into the default ring buffer after memory is set up. That may be
> the easiest way.
> Once memory is set up, the ring buffer can be allocated and events can
> be traced, but the ring buffer needs to be set up first. All it would
> take is some calls in init/main.c start_kernel() to the initialization.

Note that my main concern is on trace_events (kmem events to be precise).
However this are registered through tracepoints and in turn this tracepoints
depend on kmalloc and friends. So, right now is a chicken-egg problem.


 \ /
  Last update: 2012-08-17 16:21    [W:0.053 / U:3.200 seconds]
©2003-2017 Jasper Spaans. hosted at Digital OceanAdvertise on this site