리눅스 커널 4와 5와 6의 차이점을 알려줘
The Linux kernel has evolved significantly from version 4 to version 6, with each major release introducing new features, improvements, and support for additional hardware. Here is a detailed comparison of some key differences between Linux kernel versions 4, 5, and 6:
## **Linux Kernel 4.x**
- **Live Patching**: Introduced live patching to apply security updates without rebooting the system[3].
- **DAX (Direct Access)**: Added support for persistent memory storage, allowing filesystems to bypass the kernel cache[3].
- **kasan (Kernel Address Sanitizer)**: Implemented a dynamic memory error detector to find bugs like use-after-free and out-of-bounds errors[3].
- **OverlayFS Enhancements**: Enabled multiple lower layers in OverlayFS for more flexible filesystem management[3].
- **Parallel NFS (pNFS)**: Supported pNFS server architecture to improve scalability and performance by separating data and metadata paths[3].
## **Linux Kernel 5.x**
- **Hardware Support**: Improved support for newer hardware, including various SoCs and CPUs[4].
- **Performance Improvements**: Enhanced locking mechanisms and reduced memory fragmentation events by over 90%[4].
- **Security Features**: Introduced kernel lockdown functionality to restrict certain kernel capabilities even for root users[4].
- **Networking Enhancements**: Enabled zero-copy networking for improved UDP performance[4].
- **Memory Management**: Enhanced out-of-memory (OOM) reporting and improved memory compaction to reduce latency[4].
## **Linux Kernel 6.x**
- **Architecture Support**: Added support for AArch64 hardware architecture, NVMe in-band authentication, and PCI buses in OpenRISC and LoongArch architectures[1][2].
- **Performance Enhancements**: Introduced async buffered writes with XFS and io_uring, as well as io_uring zero-copy network transmission support[1][2].
- **Security Improvements**: Implemented fetching random-number seeds from bootloader setup data, SafeSetID security module enhancements, and ARIA encryption algorithm support[1][2].
- **Virtualization**: Added a guest vCPU stall detector as a watchdog for virtual machines and new BPF helpers for SYN cookie generation[1][2].
- **Filesystem Improvements**: Enhanced POSIX access control lists on OverlayFS filesystems and introduced the second generation of the Btrfs "send" protocol for large data transfers[1][2].
Each major version of the Linux kernel builds upon its predecessors by adding new features, improving performance, enhancing security, and expanding hardware compatibility. These changes reflect ongoing efforts to keep the Linux kernel robust and adaptable to modern computing needs.
인용:
[1] Linux Kernel 6.0 Officially Released, This Is What's New - 9to5Linux https://9to5linux.com/linux-kernel-6-0-officially-released-this-is-whats-new
[2] Linux kernel 6.0 - Stackscale https://www.stackscale.com/blog/linux-kernel-6-0/
[3] Linux_4.0 - Linux Kernel Newbies https://kernelnewbies.org/Linux_4.0
[4] Linux Kernel changes in 5.x for i.MX users and developers https://community.nxp.com/t5/i-MX-Processors-Knowledge-Base/Linux-Kernel-changes-in-5-x-for-i-MX-users-and-developers/ta-p/1121022
[5] Kernel Versions - 4.19.143 vs 5.6.18 - FOG Project forum https://forums.fogproject.org/topic/14732/kernel-versions-4-19-143-vs-5-6-18
[6] Linux kernel version history - Wikipedia https://en.wikipedia.org/wiki/Linux_kernel_version_history