[Openmp-commits] [PATCH] D104418: [PoC][WIP][OpenMP][Offloading] Fixed data race in libomptarget caused by async data movement

[Shilei Tian via Phabricator via Openmp-commits]

tianshilei1992 added inline comments.


================
Comment at: openmp/libomptarget/src/omptarget.cpp:591
+        while (TPR.MapTableEntry->Event->load() == nullptr)
+          ;
+        int Ret = Device.waitEvent(TPR.MapTableEntry->Event->load(), AsyncInfo);
----------------
jdoerfert wrote:
> I don't get why we need this. At the moment at which we are looking at the Entry I would expect it has an event or not, but neither is cause for waiting. When a new entry is created it should only be exposed to others once the event has been setup as well. Plugins that don't need events can just use nullptr without it being a problem. If this is not a problem, I suspect we want a separate flag in the entry for the status. The event should be allows to be null, the flag can be "in_progress" which indicates the rest needs to wait.
This can be removed when this whole bunch of thing is moved to the new function in D104555, otherwise it can still happen that the new entry is created but data movement has not been issued because this function is not guarded by the lock.


Repository:
  rG LLVM Github Monorepo

CHANGES SINCE LAST ACTION
  https://reviews.llvm.org/D104418/new/

https://reviews.llvm.org/D104418