Reference counting changes #1951
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Codecov ReportAttention: Patch coverage is
Additional details and impacted files@@ Coverage Diff @@
## main #1951 +/- ##
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- Coverage 81.87% 68.09% -13.79%
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Files 94 93 -1
Lines 24006 20392 -3614
Branches 3199 3047 -152
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- Hits 19655 13886 -5769
+ Misses 4276 3966 -310
- Partials 75 2540 +2465 ☔ View full report in Codecov by Sentry. |
Operations that might be performed during teardown, such as reaping, waiting, closing, freeing, should only be done if the aio has properly been initialized. This is important for certain simple cases where inline aio objects are used, and initialization of an outer object can fail before the enclosed aio is initialized.
Once a context has started the process of close, further attempts to close it will return NNG_ECLOSED. What was I thinking to ever do anything else?
This starts by using this for the nni_pipe, but we will use it for the other primary objects as well. This should simplify the tear down and hopefully eliminate some races. It does mean that pipe destruction goes through an additional context switch, for now at least. This shouldn't be on the hot data path anyway.
This uses simple reference counters for now that should be simpler, and hopefully more reliable.
This is a major change, but it should eliminate some of the problems we have seen with use-after-free bugs in shutdown. It should also be faster as we don't need to use locks as much.
This updates the pipe to use contiguous data for the transport data as well as the pipe protocol data. It updates sockfd to use this, and eliminates the need for the sockfd transport to do its own asynchronous reaping, thereby hopefully closing a shutdown race. The other transports will shortly get the same treatment. Also fixed valgrind complaint about uninitialized data in the socket test.
This avoids certain kinds of challenging deadlocks during finalization, but it does require users of the optimized nni_aio_init function to explicitly call nni_aio_stop before doing nni_aio_fini. As a minor benefit, this should reduce the number of mutex entry/exit blocks for very short lived objects (such as rapidly recycling contexts).
If an error occurs, the application gets to know about it. There cannot be external factors that cause us to spin for memory, since this is not accessible via the network.
This particular problem reported by the sanitizer was unlikely to have any real impact, but using this boolean and avoiding the clearing of the expire_q avoids a possible NULL pointer dereference.
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This converts the main part of NNG to use reference counting atomics efficiently, instead of some other hacky approaches using locks. It should be safer, and faster both!