[jdk11u-dev] RFR: 8234930: Use MAP_JIT when allocating pages for code cache on macOS [v2]

[Thomas Stuefe]

On Tue, 2 Nov 2021 20:05:45 GMT, Vladimir Kempik <vkempik at openjdk.org> wrote:

>> Please review this backport of JDK-8234930 to jdk11u-dev.
>> This is a prerequest for mac-aarch64
>> It's not applying clean due to the miss of these two patches
>> JDK-8253639: Change os::attempt_reserve_memory_at parameter order
>> JDK-8253650: Cleanup: remove alignment_hint parameter from os::reserve_memory
>> But they aren't critical and the patch can easily be modified
>
> Vladimir Kempik has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix up windows

Hi Vladimir,

sorry, I have to pull back from this review for lack of time. I wish some minimal mac-os specific hack were possible to get MAP_JIT working, instead of downporting this chain of large patches. That would be way easier to review and would limit unintended side effects to just one platform. E.g. what about just always unconditionally passing map_jit in os::reserve_memory? Just throwing ideas out here.

I'll recheck your current patch with PPC64. I remember also seeing problems on Windows, but I have to double check, maybe it was a different issue.

Cheers, Thomas

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/580