From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756284AbYKQCgh (ORCPT ); Sun, 16 Nov 2008 21:36:37 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1754664AbYKQCg1 (ORCPT ); Sun, 16 Nov 2008 21:36:27 -0500 Received: from yx-out-2324.google.com ([74.125.44.29]:53368 "EHLO yx-out-2324.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754657AbYKQCg0 (ORCPT ); Sun, 16 Nov 2008 21:36:26 -0500 Message-ID: Date: Sun, 16 Nov 2008 18:36:25 -0800 From: "Steven Noonan" To: "Frederic Weisbecker" Subject: Re: [PATCH 2/3] tracing/ftrace: make nop tracer using tracer flags Cc: "Ingo Molnar" , "Steven Rostedt" , "Linux Kernel" In-Reply-To: <4920D494.1010108@gmail.com> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline References: <4920D494.1010108@gmail.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sun, Nov 16, 2008 at 6:19 PM, Frederic Weisbecker wrote: > Impact: give an example on how to use specific tracer flags > > This patch propose to use the nop tracer to provide an > example for using the tracer's custom flags implementation. > > Signed-off-by: Frederic Weisbecker > --- > kernel/trace/trace_nop.c | 48 ++++++++++++++++++++++++++++++++++++++++++++++ > 1 files changed, 48 insertions(+), 0 deletions(-) > > diff --git a/kernel/trace/trace_nop.c b/kernel/trace/trace_nop.c > index 0e77415..1d8b4f8 100644 > --- a/kernel/trace/trace_nop.c > +++ b/kernel/trace/trace_nop.c > @@ -41,6 +41,52 @@ static void nop_trace_reset(struct trace_array *tr) > stop_nop_trace(tr); > } > > +#define TRACE_NOP_OPT_ACCEPT 0x1 > +#define TRACE_NOP_OPT_REFUSE 0x2 > +/* Options for the tracer (see trace_options file) */ > +static struct tracer_opt nop_opts[] = { > + /* Option that will be accepted by set_flag callback */ > + { TRACER_OPT(test_nop_accept, TRACE_NOP_OPT_ACCEPT) }, > + /* Option that will be refused by set_flag callback */ > + { TRACER_OPT(test_nop_refuse, TRACE_NOP_OPT_REFUSE) }, > + { } /* Always set the last empty entry */ > +}; > + > +static struct tracer_flags nop_flags = { > + /* You can check your flags value here when you want. */ > + .val = 0, /* By default: all flags disabled */ > + .opts = nop_opts > +}; I'd like these #defines and structs moved to just after the #includes, for cleanliness. > + > +/* It only serves as a signal handler and a callback to > + * accept or refuse tthe setting of a flag. > + * If you don't implement it, then the flag setting will be > + * automatically accepted. > + */ > +static int nop_set_flag(u32 old_flags, u32 bit, int set) > +{ > + /* > + * Note that you don't need to update nop_flags.val yourself. > + * The tracing Api will do it automatically if you return 0 > + */ > + if (bit == TRACE_NOP_OPT_ACCEPT) { > + printk(KERN_DEBUG "nop_test_accept flag set to %d: we accept." > + " Now cat trace_options to see the result\n", > + set); > + return 0; > + } > + > + if (bit == TRACE_NOP_OPT_REFUSE) { > + printk(KERN_DEBUG "nop_test_refuse flag set to %d: we refuse." > + "Now cat trace_options to see the result\n", > + set); > + return -EINVAL; > + } > + > + return 0; > +} > + > + > struct tracer nop_trace __read_mostly = > { > .name = "nop", > @@ -49,5 +95,7 @@ struct tracer nop_trace __read_mostly = > #ifdef CONFIG_FTRACE_SELFTEST > .selftest = trace_selftest_startup_nop, > #endif > + .flags = &nop_flags, > + .set_flag = nop_set_flag > }; > > -- > 1.5.2.5 > Other than the change noted above, I think it looks good. Acked-by: Steven Noonan