Notable features from Linux Weather Forecast by Jonathan Corbet:
- Basic support for applying patches to a running kernel, allowing the application of fixes without the need to reboot the system. There is still work to be done to get to a fully featured live-patching system, but the foundation is there in 4.0.
- The remap_file_pages() system call has been removed. Emulation of its functionality remains, though, so applications should not break.
- The kernel's support for large nonvolatile memory devices has improved considerably.
- The lazytime mount option allows for more efficient and accurate tracking of file access times.
- The kernel address sanitizer (KASan) is an important new development tool for ensuring that the kernel is not accessing memory that it shouldn't.
- Basic support for applying patches to a running kernel, allowing the application of fixes without the need to reboot the system. There is still work to be done to get to a fully featured live-patching system, but the foundation is there in 4.0.
- The remap_file_pages() system call has been removed. Emulation of its functionality remains, though, so applications should not break.
- The kernel's support for large nonvolatile memory devices has improved considerably.
- The lazytime mount option allows for more efficient and accurate tracking of file access times.
- The kernel address sanitizer (KASan) is an important new development tool for ensuring that the kernel is not accessing memory that it shouldn't.