[jdk21u-dev] RFR: 8313319: [linux] mmap should use MAP_FIXED_NOREPLACE if available [v2]

[Sergey Chernyshev]

> Hi all,
> 
> Please review the backport of JDK-8313319 that prevents unnecessary mmap-munmap cycle in systems that do not honor the address hint when mmapping memory without MAP_FIXED. Please see more details in #2475. This is (almost) a clean backport, with only a minor context conflict due to JDK-8315923 hasn't been backported to JDK 21.
> 
> Testing:
> 
> - jtreg standard test groups passed
> - gtests passed

Sergey Chernyshev has updated the pull request incrementally with one additional commit since the last revision:

  fix the double definition that came from 8330520

-------------

Changes:
  - all: https://git.openjdk.org/jdk21u-dev/pull/2476/files
  - new: https://git.openjdk.org/jdk21u-dev/pull/2476/files/1c7c3805..15e6daac

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2476&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=2476&range=00-01

  Stats: 10 lines in 1 file changed: 0 ins; 10 del; 0 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/2476.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/2476/head:pull/2476

PR: https://git.openjdk.org/jdk21u-dev/pull/2476