FreeBSD Kernel

• Several million lines of code

• Many complex subsystems

  • Memory allocation, VM, VFS, network stack, System V IPC, POSIX IPC, ...

• FreeBSD 5.x

  • Most major subsystems except VFS and some drivers execute Giant-free
  • Some network protocols require Giant

• FreeBSD 6.x almost completely Giant-free

  • VFS also executes Giant-free, although some file systems are not
  • Some straggling device drivers require Giant