On Thu, 8 Jun 2023 13:37:33 GMT, Adam Sotona <asot...@openjdk.org> wrote:
>> Classfile context object and multi-state options have been discussed at >> https://mail.openjdk.org/pipermail/classfile-api-dev/2023-May/000321.html >> This patch implements the proposed changes in Classfile API and fixes all >> affected code across JDK sources and tests. >> >> Please review. >> >> Thanks, >> Adam > > Adam Sotona has updated the pull request incrementally with one additional > commit since the last revision: > > Revert "ClassHierarchyResolver::ofSystem is now thread-unsafe" > > This reverts commit f3099cd5b252924392995bf65edc710c27822d2b. Most entities in the system are immutable and therefore freely sharable without additional coordination. Some have lazily-inflated single-field caches that conform to the "benign race" (there is only one possible non-default value) criteria. The main hole is the CHA resolution cache. There are two ways to address this: protect the cache, or don't share the context. Unfortunately now that ClassModel refers back to the context, there's a risk of unexpected context sharing. Here are a few options: - Make the CHA cache thread-safe using, say, CHM; - Make the CHA cache unshared, by using a ThreadLocal (this brings the context back to being immutable) - Detect when implicit use of a context happens on a thread other than the creating thread (currently the only vector for this is Classfile::transform), and inflate a new context with empty cache in that case; - Always create a fresh context with an empty cache in Classfile::transform On 6/8/2023 9:24 AM, Adam Sotona wrote: > > Unfortunately thread-unsafe context makes sharing of it in tests > executed in parallel a nightmare. > I can fix our Corpus tests and hope the race condition won't raise > also somewhere else later. > However how to explain this limitation to users? > > I suggest to make it always thread-safe (as the context is primary > expected to be shared in multi-threaded environment) and users may > make it faster in specific cases by providing non-synchronized map. > > — > Reply to this email directly, view it on GitHub > <https://github.com/openjdk/jdk/pull/14180#issuecomment-1582576426>, > or unsubscribe > <https://github.com/notifications/unsubscribe-auth/AABJ4RHSMWR5Q3ANYK3RPSLXKHG7RANCNFSM6AAAAAAYQLACYQ>. > You are receiving this because you commented.Message ID: > ***@***.***> > ------------- PR Comment: https://git.openjdk.org/jdk/pull/14180#issuecomment-1582643016
