Release reusability token when suspendCancellableCoroutineReusable's … #3634
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…block throws an exception Otherwise, continuation instance is left in REUSABLE_CLAIMED state that asynchronous resumer awaits in an infinite spin-loop, potentially causing deadlock with 100% CPU consumption. Originally, the bug was reproduced on old (pre-#3020) implementation where this very pattern was encountered: it was possible to fail owner's invariant check right in the supplied 'block'. This is no longer the case, so the situation is emulated manually (but still is possible in production environments, e.g. when OOM is thrown). Also, suspendCancellableCoroutineReusable is removed from obsolete BroadcastChannel implementation. Fixes #3613
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Also filed #3635 to eventually address the issue in a more systematic and graceful manner |
dkhalanskyjb
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Mar 3, 2023
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| * Note that this implementation always invokes [suspendCancellableCoroutineReusable], | ||
| * as we do not care about broadcasts performance -- they are already deprecated. |
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| * Note that this implementation always invokes [suspendCancellableCoroutineReusable], | |
| * as we do not care about broadcasts performance -- they are already deprecated. |
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Also, what did this comment mean? suspendCancellableCoroutineReusable is a slower internal version of suspendCancellableCoroutine that we use internally as a performance de-optimization, and now that BroadcastChannel is deprecated, we're free to make it fast, right?
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I believe this is just a miswording, asked Nikita to verify just in case.
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The idea was "it doesn't have non-suspending fast-path"
Co-authored-by: Dmitry Khalanskiy <[email protected]>
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…block throws an exception
Otherwise, continuation instance is left in REUSABLE_CLAIMED state that asynchronous resumer awaits in an infinite spin-loop, potentially causing deadlock with 100% CPU consumption. Originally, the bug was reproduced on old (pre-#3020) implementation where this very pattern was encountered: it was possible to fail owner's invariant check right in the supplied 'block'. This is no longer the case, so the situation is emulated manually (but still is possible in production environments, e.g. when OOM is thrown). Also, suspendCancellableCoroutineReusable is removed from obsolete BroadcastChannel implementation.
Fixes #3613