From mboxrd@z Thu Jan 1 00:00:00 1970 From: Ingo Molnar Subject: Re: [PATCH 0/3] ftrace: updates for tip Date: Thu, 4 Dec 2008 09:19:27 +0100 Message-ID: <20081204081927.GD32594@elte.hu> References: <20081203203656.776893226@goodmis.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: <20081203203656.776893226@goodmis.org> Sender: linux-kernel-owner@vger.kernel.org To: Steven Rostedt Cc: linux-kernel@vger.kernel.org, Andrew Morton , Frederic Weisbecker , Peter Zijlstra , Arjan van de Ven , Dave Hansen , containers@lists.osdl.org, Eric Biederman , Sukadev Bhattiprolu , "Serge E. Hallyn" List-Id: containers.vger.kernel.org * Steven Rostedt wrote: > Ingo, > > This series has three patches. > > The first patch adds a new feature that I've been wanting to have for some > time and Arjan even requested. That is to pick a function and only > trace that function and its children. Dynamic ftrace and function > graph needs to be enabled for this. > > To do the above, I added a "trace" flags field in the task structure. > The second patch uses this for the ftrace pid code. It searches for > the task based on the pid and sets the trace flag, then in the > ftrace function caller it only needs to check this flag. > > This means we can now trace more than one pid without any more overhead. > It also means that we should be able to use the name space code that > the container guys want us to. But since I'm not very up on the > namespace code, I'm still using just the normal 'pid'. I've Cc'd the > container folks so perhaps they could write up a patch for me ;-) > > Note: When writing to the set_ftrace_pid two things happen. > - The task with the matching pid gets the trace flag set. > - Any other task has its trace flag cleared. > #2 needs to be addressed when converting to pid name spaces. > Just because it is not enough to simply find the matching task. > It may be good enough to just clear all tasks and then find the > one that matches. > > The last patch makes the function graph tracer honor the set_ftrace_pid. > > The following patches are in: > > git://git.kernel.org/pub/scm/linux/kernel/git/rostedt/linux-2.6-trace.git > > branch: tip/devel > > > Steven Rostedt (3): > ftrace: graph of a single function > ftrace: use task struct trace flag to filter on pid > ftrace: trace single pid for function graph tracer > > ---- > include/linux/ftrace.h | 46 +++++++++ > include/linux/sched.h | 4 + > kernel/trace/ftrace.c | 257 +++++++++++++++++++++++++++++++++++++++++++++++- > kernel/trace/trace.c | 11 ++ > kernel/trace/trace.h | 40 +++++++- > 5 files changed, 353 insertions(+), 5 deletions(-) > -- pulled, thanks Steve! These are some very nice changes! Ingo