[jdk11u-dev] RFR: 8253638: Cleanup os::reserve_memory and remove MAP_FIXED [v2]

[Thomas Stuefe]

On Tue, 2 Nov 2021 07:58:59 GMT, Vladimir Kempik <vkempik at openjdk.org> wrote:

> Hello Thomas. I have built solaris (hotspot only, as harfbuzz is broken currently in openjdk11u).
> 
> I think it would be just these two.
> 
> https://bugs.openjdk.java.net/browse/JDK-8255254 Split os::reserve_memory and os::map_memory_to_file interfaces https://bugs.openjdk.java.net/browse/JDK-8234930 Use MAP_JIT when allocating pages for code cache on macOS
> 
> as I first did 8255254, and it wasn't easy because of missing 8253638. Then I have tried to do 8234930 on top of 8255254 and realised I really need 8253638. So I think we can make it to just these three - 8253638 8255254 8234930
> 
> This backport is not clean and has additional changes in solaris support and os_windows.cpp was very different from jdk17 Also few more NULL argument removals from call to reserve_memory in SafePointMechanism.cpp
> 
> We have in-house MAP_JIT patch ( used for zulu11 for mac-aarch64) and it's very different from these three. Not sure we really wanna go this route and differ so much from upstream
> 
> The testing - GHA performed tier1 already, I will run additionally full regression testing and report later

Hi Vladimir, 

thanks for the clarification. I added this patch to our 11u dev test landscape to let it cook a bit. I'd also like to wait for input from others (Anton, @stefank, maybe @kstefanj).

Cheers, Thomas

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PR: https://git.openjdk.java.net/jdk11u-dev/pull/574