Messages in this thread | | | Date | Mon, 18 Mar 2013 09:46:10 -0700 | From | Tejun Heo <> | Subject | Re: workqueue code needing preemption disabled |
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On Mon, Mar 18, 2013 at 12:41:23PM -0400, Steven Rostedt wrote: > But, I'm worried about the loops that are done while holding this lock. > Just looking at is_chained_work() that does for_each_busy_worker(), how > big can that list be? If it's bound by # of CPUs then that may be fine, > but if it can be as big as the # of workers assigned, with no real > limit, then its not fine, because that creates an unbound (non > deterministic) latency.
In most paths, gcwq->lock shouldn't be held for too long but yes there are cold paths which just do things without thinking about latency issues. is_chained_work() can definitely take pretty long time (note that it got reimplemented in the current devel branch and the loop is gone).
-- tejun
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