Re: [PATCH 0/7] add syscall tracepoints
From: Frederic Weisbecker
Date: Thu Jun 18 2009 - 23:07:53 EST
On Tue, Jun 16, 2009 at 09:32:20PM +0200, Ingo Molnar wrote:
> * Jason Baron <jbaron@xxxxxxxxxx> wrote:
> > hi,
> > The following is an implementation of Frederic's syscall tracer on
> > top of tracepoints. It adds the ability to toggle the entry/exit
> > of each syscall via the standard
> > events/syscalls/syscall_blah/enable interface. The implementation
> > is done by adding 2 tracepoints. One on entry and one for exit.
> > This implementation required a few 'core' api changes. I've added
> > 'DECLARE_TRACE_REG()' macro which takes a register and and an
> > unregister function as arguments. This allowed me to toggle the
> > ftrace tif flag when the first tracepoint callback is added and
> > the last is removed. Current callers of 'DECLARE_TRACE()' are not
> > impacted.
> > Another change was to call arch_init_ftrace_syscalls via an
> > 'arch_initall'. In this implmentation I needed to access the
> > syscalls_metadata structure at runtime in order to determine which
> > syscalls were 'traceable'. Although the implementation uses
> > SYSCALL_DEFINE() to set up the the trace events, for some reason
> > at runtime there is no syscalls_metadata, associated with some of
> > the SYSCALL_DEFINE() calls. I'm not quite sure why that is.
> > However, by calling arch_init_ftrace_syscalls() at boot I can make
> > sure the lists are in sync.
> > thanks,
> > -Jason
> > arch/x86/include/asm/ftrace.h | 4 +-
> > arch/x86/kernel/ftrace.c | 24 +++++-
> > arch/x86/kernel/ptrace.c | 6 +-
> > include/linux/syscalls.h | 63 +++++++++++++++
> > include/linux/tracepoint.h | 27 ++++++-
> > include/trace/syscall.h | 37 +++++++---
> > kernel/trace/trace_events.c | 29 +++++---
> > kernel/trace/trace_syscalls.c | 172 +++++++++++++++++++----------------------
> > kernel/tracepoint.c | 38 +++++++++
> > 9 files changed, 278 insertions(+), 122 deletions(-)
> This looks far nicer structurally. Steve, Frederic, what's your take
> on this series?
I've reviewed all of them and only found small neats to comment.
Yeah the direction looks better now.
Acked-by: Frederic Weisbecker <fweisbec@xxxxxxxxx>
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