Messages in this thread | | | Date | Thu, 9 Dec 2010 18:00:32 +0100 | From | Frederic Weisbecker <> | Subject | Re: [RFC PATCH] ftrace trace event: introduce assignment macros |
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On Thu, Dec 09, 2010 at 11:22:11AM -0500, Mathieu Desnoyers wrote: > This patch proposes encapsulation of the raw assignments within TP_fast_assign() > by introducing tp_assign() and tp_memcpy() macros. This will allow us to: > > - generically filter from input fields, > - redefine the field write primitives. > > The current macros map directly to the old code. I changed the documentation in > tracepoint.txt to reflect these new primitives, but all TRACE_EVENT() users > should gradually update their code to use these macro wrappers rather than raw > "=" assignments or mempcy() calls. > > Signed-off-by: Mathieu Desnoyers <mathieu.desnoyers@efficios.com> > CC: Steven Rostedt <rostedt@goodmis.org> > CC: Frederic Weisbecker <fweisbec@gmail.com> > CC: Ingo Molnar <mingo@redhat.com> > CC: Li Zefan <lizf@cn.fujitsu.com> > CC: William Cohen <wcohen@redhat.com> > CC: Jun'ichi Nomura <j-nomura@ce.jp.nec.com> > CC: Theodore Ts'o <tytso@mit.edu> > CC: Jason Baron <jbaron@redhat.com> > CC: Mel Gorman <mel@csn.ul.ie> > CC: Eduard - Gabriel Munteanu <eduard.munteanu@linux360.ro> > CC: Marcelo Tosatti <mtosatti@redhat.com> > CC: Avi Kivity <avi@redhat.com> > CC: Gleb Natapov <gleb@redhat.com> > CC: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com> > CC: Neil Horman <nhorman@tuxdriver.com> > CC: Arjan van de Ven <arjan@linux.intel.com> > CC: Peter Zijlstra <a.p.zijlstra@chello.nl> > CC: Kei Tokunaga <tokunaga.keiich@jp.fujitsu.com> > CC: Martin K. Petersen <martin.petersen@oracle.com> > CC: Oleg Nesterov <oleg@redhat.com> > CC: Masami Hiramatsu <mhiramat@redhat.com> > CC: Josh Stone <jistone@redhat.com> > CC: Xiao Guangrong <xiaoguangrong@cn.fujitsu.com> > CC: Thomas Gleixner <tglx@linutronix.de> > CC: Zhaolei <zhaolei@cn.fujitsu.com> > CC: Anton Blanchard <anton@samba.org> > --- > include/linux/tracepoint.h | 12 ++++++------ > include/trace/ftrace.h | 6 ++++++ > 2 files changed, 12 insertions(+), 6 deletions(-) > > Index: linux-2.6-lttng.git/include/trace/ftrace.h > =================================================================== > --- linux-2.6-lttng.git.orig/include/trace/ftrace.h > +++ linux-2.6-lttng.git/include/trace/ftrace.h > @@ -1,4 +1,10 @@ > /* > + * Macros mapping tp_assign() and tp_memcpy() to "=" and memcpy. > + */ > +#define tp_assign(dest, src) __entry->dest = src > +#define tp_memcpy(dest, src, len) memcpy(__entry->dest, src, len)
Looks good.
> + > +/* > * Stage 1 of the trace events. > * > * Override the macros in <trace/trace_events.h> to include the following: > Index: linux-2.6-lttng.git/include/linux/tracepoint.h > =================================================================== > --- linux-2.6-lttng.git.orig/include/linux/tracepoint.h > +++ linux-2.6-lttng.git/include/linux/tracepoint.h > @@ -306,12 +306,12 @@ static inline void tracepoint_update_pro > * * > * > * TP_fast_assign( > - * memcpy(__entry->next_comm, next->comm, TASK_COMM_LEN); > - * __entry->prev_pid = prev->pid; > - * __entry->prev_prio = prev->prio; > - * memcpy(__entry->prev_comm, prev->comm, TASK_COMM_LEN); > - * __entry->next_pid = next->pid; > - * __entry->next_prio = next->prio; > + * tp_memcpy(next_comm, next->comm, TASK_COMM_LEN); > + * tp_assign(prev_pid, prev->pid); > + * tp_assign(prev_prio, prev->prio); > + * tp_memcpy(prev_comm, prev->comm, TASK_COMM_LEN); > + * tp_assign(next_pid, next->pid); > + * tp_assign(next_prio, next->prio); > * ) > * > * * > > -- > Mathieu Desnoyers > Operating System Efficiency R&D Consultant > EfficiOS Inc. > http://www.efficios.com
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