On Fri, 1 Nov 2024 02:44:15 GMT, Quan Anh Mai <qa...@openjdk.org> wrote:
>> Hi, >> >> This patch makes `MemorySessionImpl.state` a `Stable` field so that liveness >> check of non-closeable scopes such as the global scope can be elided. >> >> Currently, the `state` field is overloaded with 2 responsibilities, to act >> as a communication device between `close` and `checkValidState`, as well as >> a communication device between `close`, `acquire`, and `release`. This patch >> separates those concerns into `state` and `acquireCount`, allowing `state` >> to be marked as `@Stable`. >> >> With the patch, in `MemorySegmentGetUnsafe`, `panama` is able to be on par >> with `unsafe`: >> >> Benchmark Mode Cnt Score Error Units >> MemorySegmentGetUnsafe.panama avgt 30 0.340 ± 0.008 ns/op >> MemorySegmentGetUnsafe.unsafe avgt 30 0.332 ± 0.004 ns/op >> >> For reference this is the results without this patch: >> >> Benchmark Mode Cnt Score Error Units >> MemorySegmentGetUnsafe.panama avgt 30 0.420 ± 0.019 ns/op >> MemorySegmentGetUnsafe.unsafe avgt 30 0.329 ± 0.003 ns/op >> >> Please kindly review, thanks very much. > > Quan Anh Mai has updated the pull request incrementally with one additional > commit since the last revision: > > wait for the close operation to complete on acquire failures src/java.base/share/classes/jdk/internal/foreign/SharedSession.java line 90: > 88: } > 89: > 90: STATE.setOpaque(this, CLOSED); Why are we using opaque semantics here and not volatile? ------------- PR Review Comment: https://git.openjdk.org/jdk/pull/21810#discussion_r1825600258
