RFR(S) 8067331: Zero: Atomic::xchg and Atomic::xchg_ptr need full memory barrier
coleen.phillimore at oracle.com
Wed Jan 7 04:54:08 UTC 2015
This looks good. Sorry for the delay reviewing it as it looks
important. Is there a small test case that can be written to test
this? (or no?)
On 1/6/15, 8:47 PM, David Holmes wrote:
> Can we get a second hotspot review please - this is quite straight
> 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 -
>>> and Atomic::xchg_ptr - use GCC's built-in __sync_lock_test_and_set
>>> 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
>> I can sponsor this but we still need a second review.
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