On Tue, 2013-08-27 at 16:01 -0400, Steven Rostedt wrote: > On Tue, 27 Aug 2013 14:40:13 -0500 > Tom Zanussi <tom.zanu...@linux.intel.com> wrote: > > return; > > - if (!test_bit(syscall_nr, tr->enabled_enter_syscalls)) > > + > > + /* Here we're inside the tp handler's rcu_read_lock (__DO_TRACE()) */ > > + ftrace_file = rcu_dereference_raw(tr->enter_syscall_files[syscall_nr]); > > What's the reason for using rcu_dereference_raw() and not normal > rcu_dereference? >
This is because we know the tracepoint handler has rcu_read_lock_held() and so we don't need to do the rcu_dereference_check(). Tom > -- Steve > > > + if (!ftrace_file) > > + return; > > + > > + if (test_bit(FTRACE_EVENT_FL_SOFT_DISABLED_BIT, &ftrace_file->flags)) > > return; > > -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majord...@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
