FPreloadShaderTask takes the ShaderPreloadLock in FShaderCodeArchive::OnShaderPreloadFinished() and then issues an async read. Another task can be picked up by the thread while waiting on that read. If that new task is also a FPreloadShaderTask it will try to aquire the ShaderPreloadLock again and deadlock.
Introduce an EnsureReadNonBlocking method to IMemoryReadStream which can be called outside the lock to ensure the data is ready. We can then lock and copy out the data without incuring a wait and the potential for another FPreloadShaderTask being run while we hold the lock.
#rb Ben.Ingram, Michal.Valient
#ROBOMERGE-SOURCE: CL 16917416 via CL 16924675
#ROBOMERGE-BOT: STARSHIP (Main -> Release-Engine-Test) (v836-16769935)
[CL 16925027 by eric mcdaniel in ue5-release-engine-test branch]
- FileCache can dynamically allocate/release memory as needed
- Preloaded lines are locked in the cache. One the preloaded memory has been read, the line is unlocked. This prevents preloaded lines from being evicted before they're needed.
- Cache line size changed from 64k to 16k, reduce fragmentation due to locked preloaded lines
#rb none
#ROBOMERGE-SOURCE: CL 12491121 via CL 12491126 via CL 12491130
#ROBOMERGE-BOT: RELEASE (Release-Engine-Staging -> Main) (v673-12478461)
[CL 12491133 by ben ingram in Main branch]
Add extra logging to try to get more information about crash
#rb none
#ROBOMERGE-SOURCE: CL 11964426 in //UE4/Release-4.25/... via CL 11964431
#ROBOMERGE-BOT: RELEASE (Release-4.25Plus -> Main) (v656-11643781)
[CL 11964452 by ben ingram in Main branch]
