Linux 6.2

Date: 2023-02-20T15:48:00-08:00


Linux 6.2 is out. Among its marquee updates are improved Rust-in-kernel support (strings, formatting and printing, memory allocation, macros, etc.), adding TCP Protective Load Balancing (PLB) for IPv6, reducing the overhead of read-copy update (RCU) operations using lazy callbacks, performance and RAID improvements for Btrfs, and userspace support for runtime verification with safety-critical systems. And, of course, support for Apple silicon and Retbleed sucks less on Skylake, but who cares about that around here anyway?

On the Power ISA side, probably the most noteworthy change is official support for big endian ELFv2 kernels. A nice upgrade for our Sir Mix-A-Lot brigade! Another interesting commit is the one to allow compile time support for the lharx and lbarx instructions (present on ISA v2.06/POWER7 and up). The lwarx (32-bit word) and ldarx (64-bit doubleword) load instructions, along with the corresponding store instructions stwcx. and stdcx. (and a conditional branch), are used to implement atomic load-store-compare/exchange operations by placing and checking reservations on particular memory locations. The newer instructions can do this at halfword (short) and byte level respectively (with sthcx. and stbcx.) instead of reserving at least an entire 32-bit word, reducing contention in tightly packed structs. In the future, it might also benefit the newly introduced Power ISA-specific spinlock implementation as well, which is also new in this release.

Expect 6.2 to make it to bleeding edge users and Fedora in the very near future.