Messages in this thread | | | Date | Tue, 14 Mar 2006 20:36:31 +0300 | From | Oleg Nesterov <> | Subject | Re: [PATCH] task: Make task list manipulations RCU safe. |
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Some questions.
first_tgid: ... for (; pos && pid_alive(pos); pos = next_task(pos))
I think this patch makes this 'pid_alive(pos)' unneeded?
next_tgid: rcu_read_lock(); pos = start; if (pid_alive(start)) pos = next_task(start); if (pid_alive(pos) && (pos != &init_task)) { get_task_struct(pos); goto done; }
The first 'pid_alive()' check is quite understandable. What about the second one? I beleive, now it is unneeded as well. The same for first_tid/next_tid.
Also, first_tid() does 'task_lock(leader)' while reading ->signal->count. Why? ->signal is protected by ->siglock, but we don't need any locks because ->signal is rcu safe. Same for proc_task_getattr(), s/task_lock/rcu_read_lock/.
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