RFR: JDK-8294947: Use 64bit atomics in patch_verified_entry on x86_64 [v3]

[Vladimir Kozlov]

On Mon, 14 Nov 2022 16:44:27 GMT, Dmitry Samersoff <dsamersoff at openjdk.org> wrote:

>> In the void NativeJump::patch_verified_entry() we atomically patch first 4 bytes, then atomically patch 5th byte, then atomically patch first 4 bytes again. But from CMC (cross-modified code) point of view it's better to patch atomically 8 bytes at once.
>> 
>> The patch was tested with hotspot jtreg tests in bare-metal and virtualized environments.
>
> Dmitry Samersoff has updated the pull request incrementally with one additional commit since the last revision:
> 
>   8294947: Use 64bit atomics in patch_verified_entry on x86_64

My testing passed.

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Marked as reviewed by kvn (Reviewer).

PR: https://git.openjdk.org/jdk/pull/11059