Messages in this thread |  | | Date | Wed, 13 Nov 2013 15:35:52 +0100 | From | Oleg Nesterov <> | Subject | [PATCH 0/3] state/exit_state cleanups (Was: Remove unused variable ret from sync_thread_master()) |
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On 11/12, Oleg Nesterov wrote: > > On 11/12, Peter Zijlstra wrote: > > > > We have to put in something... > > > > BUILD_BUG_ON(1 + ilog2(TASK_STATE_MAX) != ARRAY_SIZE(task_state_array)); > > > > However, since we always set it together with TASK_UNINTERUPTIBLE > > userspace shouldn't actually ever see the I thing. > > OOPS. I didn't know that get_task_state() does &= TASK_REPORT. So it > can never report anything > EXIT_DEAD. > > Perhaps we should change BUILD_BUG_ON() and shrink task_state_array?
Seriously, imho this looks confusing enough and deserves a cleanup.
As for "nobody should use exit_state". I'll try to recheck, but iirc we already discussed this... do you remember any reason why schedule_debug() can't check prev->state == TASK_DEAD instead of ->exit_state?
Note that ->exit_state is not exactly right, it is set by exit_notify() but in_atomic_preempt_off() should be only ignored when the task does the last schedule() in TASK_DEAD.
Oleg.
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