circuit_unlink_all_from_channel() is a performance bottleneck?
In https://lists.torproject.org/pipermail/tor-relays/2013-September/002715.html Andy reports some profiling on his fast exit. Top on his list is
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19.37% tor circuit_unlink_all_from_channelIt looks like that function crawls the whole circuit list every time we close a connection. With circuit lists being huge these days, it is plausible that it takes a lot of effort to crawl it.
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