[SYCL] Fix hang in deallocateStreams function #2796
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This patch fixes hang caused by data race in `scheduler.cpp`'s `deallocateStreams` function: data of `StreamsToDeallocate` vector is corrupted by another thread, and due to this, it was a hang in `Scheduler::deallocateStreamBuffers` function when `StreamBuffersPool[Impl]` had been being deleted.
vladimirlaz
previously approved these changes
Nov 19, 2020
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There are some surprisingly failed LIT tests caused by this change. I'm working on resolving them. |
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@vladimirlaz, fixed patch, all LIT tests pass now, updated description. |
vladimirlaz
approved these changes
Nov 23, 2020
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This patch fixes hang caused by deadlock in
Scheduler::deallocateStreamBuffersfunction. Deadlock washappened when
StreamBuffersPool[Impl]had been beingdeleted.
StreamBuffersPool[Impl]is a pointer toStreamBuffersstructobject which has
bufferobject as a field, so the dtor ofbufferclass was called. After that the call stack is the following:
~buffer_impl()->SYCLMemObjT::updateHostMemory()->Scheduler::removeMemoryObject->deallocateStreams->Scheduler::deallocateStreamBuffers-> deadlock inlock_guard, mutex was already locked by the same thread.Changed
std::mutextostd::recursive_mutex, so nowthe same thread can enter the critical section, locked by
itself before.