Meta mode

Meta mode creats meta files when building, which provide a reliable incremental build using filemon(4). It makes building FreeBSD from source much faster if you're rebuidling it from time to time on your own.

• src.conf(5)
• build(7)

• /etc/src-env.conf:

WITH_META_MODE=YES

• kldload filemon
• You also need to make cleanworld once. If objects don't have .meta files then META_MODE won't do the right thing on an incremental build. (Source: [CFT WITH_META_MODE: Working incremental build)

Now you can follow the handbook and you should be fine.

• Don't mix WITH_META_MODE with ccache(1) as mentioned in this thread.
• WITH_META_MODE is not the same thing as WITH_DIRDEPS_BUILD, which is an alternative, experimental build system.
  • Building FreeBSD in meta mode
  • Improving the FreeBSD Build (BSDCan 2016)
  • Description of meta mode in bmake(1)
  • Speeding up builds on FreeBSD

• [CFT WITH_META_MODE: Working incremental build