Patrick Zhang

MADV_DOEXEC and MADV_DONTEXEC should be redefined within a separate numerical range

2

**Description:** MADV_DOEXEC and MADV_DONTEXEC should be redefined within a separate numerical range otherwise break binary compatibility with mainline kernels. **Diagnostic Info:** Kernel v5.4 build from [uek6/u3](https://github.com/oracle/linux-uek/tree/uek6/u3) has a commit https://github.com/oracle/linux-uek/commit/a91ae4fa327d8957e2f806420b8b835269b85bd4,...

8350483: AArch64: turn on signum intrinsics by default on Ampere CPUs

13

Backport the commit to set -XX:+UseSignumIntrinsic by default for Ampere CPUs. It is to fix performance problem observed on JMH cases `vm.compiler.Signum|java.lang.*MathBench.sig[nN]um*`. For example, `vm.compiler.Signum._1_signumFloatTest` thrpt score becomes 30x better...

8365991: AArch64: Ignore BlockZeroingLowLimit when UseBlockZeroing is false

25

Issue: In AArch64 port, `UseBlockZeroing` is by default set to true and `BlockZeroingLowLimit` is initialized to 256. If `DC ZVA` is supported, `BlockZeroingLowLimit` is later updated to `4 * VM_Version::zva_length()`....