What's new in the Linux kernel

and what's missing in Debian

Ben Hutchings

Ben Hutchings

Linux releases early and often

Recap of last year's features (1)

Recap of last year's features (2)

Unnamed temporary files [3.11]

Network busy-polling [3.11] (1)

A conventional network request/response process looks like:

  1. Task calls send(); network stack constructs a packet; driver adds it to hardware Tx queue
  2. Task calls poll() or recv(), which blocks; kernel puts it to sleep and possibly idles the CPU
  3. Network adapter receives response and generates IRQ, waking up CPU
  4. Driver's IRQ handler schedules polling of the hardware Rx queue (NAPI)
  5. Kernel runs the driver's NAPI poll function, which passes the response packet into the network stack
  6. Network stack decodes packet headers and adds packet to the task's socket
  7. Network stack wakes up sleeping task; scheduler switches to it and the socket call returns

Network busy-polling [3.11] (2)

Lustre filesystem [3.12]

Btrfs offline dedupe [3.12]

nftables [3.13]

User-space lockdep [3.14]

arm64 and ppc64el ports

File-private locking [3.15]

Multiqueue block devices [3.16]