Messages in this thread | | | Subject | Re: [PATCH 2/3] ftrace: use struct pid | From | Dave Hansen <> | Date | Thu, 04 Dec 2008 05:07:02 -0800 |
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On Thu, 2008-12-04 at 04:56 -0800, Dave Hansen wrote: > On Thu, 2008-12-04 at 04:42 -0800, Eric W. Biederman wrote: > > > > > +static void clear_ftrace_pid_task(struct pid **pid) > > > +{ > > > + struct task_struct *p; > > > + > > rcu_read_lock(); > > > > > + do_each_pid_task(*pid, PIDTYPE_PID, p) { > > > + clear_tsk_trace_trace(p); > > > + } while_each_pid_task(*pid, PIDTYPE_PID, p); > > rcu_read_unlock() > > > > > + put_pid(*pid); > > > + > > > + *pid = NULL; > > > +} > > Could we get away with sticking the rcu_read_{un}lock() inside those > macros? Those are going to get used in pretty high level code and we're > allowed to nest rcu_read_lock(). No danger of deadlocks or lock > inversions.
Why don't any of the other users of do_each_pid_task() use rcu_read_lock()? They all seem to be under read_lock(&tasklist_lock) (except one is under a write lock of the same).
-- Dave
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