[5.x] Remote: Don't blocking-get when acquiring gRPC connections. #14421
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With recent change to limit the max number of gRPC connections by default, acquiring a connection could suspend a thread if there is no available connection. gRPC calls are scheduled to a dedicated background thread pool. Workers in the thread pool are responsible to acquire the connection before starting the RPC call. There could be a race condition that a worker thread handles some gRPC calls and then switches to a new call which will acquire new connections. If the number of connections reaches the max, the worker thread is suspended and doesn't have a chance to switch to previous calls. The connections held by previous calls are, hence, never released. This PR changes to not use blocking get when acquiring gRPC connections. Fixes bazelbuild#14363. Closes bazelbuild#14416. PiperOrigin-RevId: 416282883 (cherry picked from commit ad663a7)
This was referenced Dec 14, 2021
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With recent change to limit the max number of gRPC connections by default, acquiring a connection could suspend a thread if there is no available connection.
gRPC calls are scheduled to a dedicated background thread pool. Workers in the thread pool are responsible to acquire the connection before starting the RPC call.
There could be a race condition that a worker thread handles some gRPC calls and then switches to a new call which will acquire new connections. If the number of connections reaches the max, the worker thread is suspended and doesn't have a chance to switch to previous calls. The connections held by previous calls are, hence, never released.
This PR changes to not use blocking get when acquiring gRPC connections.
Fixes #14363.
Closes #14416.
PiperOrigin-RevId: 416282883
(cherry picked from commit ad663a7)