openeuler inclusion
category: feature
bugzilla: https://gitee.com/openeuler/kernel/issues/I4L9RU
CVE: NA

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

This is the final patch in FUTEX_SWAP patchset. It
adds a test/benchmark to validate behavior and
compare performance of a new FUTEX_SWAP futex operation.

Detailed API design and behavior considerations are provided
in the commit messages of the previous two patches.
Signed-off-by: NPeter Oskolkov <posk@google.com>