RFR(S) 8067331: Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier
david.holmes at oracle.com
Wed Jan 7 01:47:20 UTC 2015
Can we get a second hotspot review please - this is quite straight forward.
On 5/01/2015 12:21 PM, David Holmes wrote:
> Hi Severin,
> Sorry this slipped through the cracks before the holidays.
> On 16/12/2014 1:09 AM, Severin Gehwolf wrote:
>> Could someone please review and sponsor the following change?
>> bug: https://bugs.openjdk.java.net/browse/JDK-8067331
>> The issue is that all atomic operations are expected to be full memory
>> barriers, but two implementations of the Zero variant JVM - Atomic::xchg
>> and Atomic::xchg_ptr - use GCC's built-in __sync_lock_test_and_set which
>> is an acquire barrier only. The fix adds full memory barriers manually
>> for those.
> Looks completely consistent with what I just saw in the aarch64 port code.
> I can sponsor this but we still need a second review.
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