----- Original Message ----- > From: "Frederic Weisbecker" <fweis...@gmail.com> > To: "LKML" <linux-kernel@vger.kernel.org> > Cc: "Frederic Weisbecker" <fweis...@gmail.com>, "Andrew Morton" > <a...@linux-foundation.org>, "Ingo Molnar" > <mi...@kernel.org>, "Mathieu Desnoyers" <mathieu.desnoy...@efficios.com>, > "Oleg Nesterov" <o...@redhat.com>, "Steven > Rostedt" <rost...@goodmis.org> > Sent: Wednesday, April 9, 2014 12:11:19 PM > Subject: [PATCH 2/5] tracepoint: Convert process iteration to use > for_each_process_thread() > > do_each_thread/while_each_thread iterators are deprecated by > for_each_thread/for_each_process_thread() APIs. > > Lets convert the callers in the tracepoint code. The ultimate > goal is to remove the struct task_struct::thread_group field and > the corresponding do_each_thread/while_each_thread iterators that are > RCU unsafe. > > Cc: Andrew Morton <a...@linux-foundation.org> > Cc: Ingo Molnar <mi...@kernel.org> > Cc: Mathieu Desnoyers <mathieu.desnoy...@efficios.com> > Cc: Oleg Nesterov <o...@redhat.com> > Cc: Steven Rostedt <rost...@goodmis.org> > Signed-off-by: Frederic Weisbecker <fweis...@gmail.com> > --- > kernel/tracepoint.c | 12 ++++++------ > 1 file changed, 6 insertions(+), 6 deletions(-) > > diff --git a/kernel/tracepoint.c b/kernel/tracepoint.c > index fb0a38a..00a7e8b 100644 > --- a/kernel/tracepoint.c > +++ b/kernel/tracepoint.c > @@ -561,15 +561,15 @@ static int sys_tracepoint_refcount; > void syscall_regfunc(void) > { > unsigned long flags; > - struct task_struct *g, *t; > + struct task_struct *p, *t; > > if (!sys_tracepoint_refcount) { > read_lock_irqsave(&tasklist_lock, flags); > - do_each_thread(g, t) { > + for_each_process_thread(p, t) {
What are the locking rules for for_each_process_thread() ? Is it required to hold RCU read-side lock ? (it's not the case here) Is tasklist_lock read-side lock sufficient ? A quick glance at those for_each iterator defines in sched.h was not helpful in finding this information. Thanks, Mathieu > /* Skip kernel threads. */ > if (t->mm) > set_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); > - } while_each_thread(g, t); > + } > read_unlock_irqrestore(&tasklist_lock, flags); > } > sys_tracepoint_refcount++; > @@ -578,14 +578,14 @@ void syscall_regfunc(void) > void syscall_unregfunc(void) > { > unsigned long flags; > - struct task_struct *g, *t; > + struct task_struct *p, *t; > > sys_tracepoint_refcount--; > if (!sys_tracepoint_refcount) { > read_lock_irqsave(&tasklist_lock, flags); > - do_each_thread(g, t) { > + for_each_process_thread(p, t) { > clear_tsk_thread_flag(t, TIF_SYSCALL_TRACEPOINT); > - } while_each_thread(g, t); > + } > read_unlock_irqrestore(&tasklist_lock, flags); > } > } > -- > 1.8.3.1 > > -- Mathieu Desnoyers EfficiOS Inc. http://www.efficios.com -- 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/