On Wed, 23 Oct 2024 05:33:55 GMT, Axel Boldt-Christmas <abold...@openjdk.org> wrote:
>> Ok, I'll change copy_lockstack to both load and clear the oops in the same >> method. Now, when we call do_barriers on recurse_thaw we don't clear the >> oops, we just load and store the loaded value again. Is it the case that we >> just need to do a store, so that already works, or are we missing clearing >> the oops from the copied frames? > > The store is the important part for SATB. The fact that do_barriers (only) > does a self store seems is an optimisation. As we need to do the store before > we do the copy (to enable a plane memcpy). And clearing is not something > that we rely on / need at the moment. The nicest model would have been to > first fix the oops, (mem)copy, then clear them. But as mentioned, clearing > is currently unnecessary. For the lockstack we do not need this optimisation > as we do the copy when we do the load barrier. So we can just clear in our > store. > > It is a little interesting that we template parameterise `do_barriers` on the > barrier type and instantiate all the load functions, while only ever using > the store version. Guess it is a remnant from some earlier model. I renamed it to transfer_lockstack() and applied the suggested version with the lambda. ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21565#discussion_r1813224287
