alt Hacker NewsContempt for stable kernel data structures and APIs (and forget about any sort of kernel ABI) might make things easier for certain kernel developers, but it offloads a constant maintenance burden onto many other people, such as eBPF, driver, and kernel extension developers.
This sort of asymmetry is why system modules, and platforms in general, should absorb pain in order to benefit their many clients, rather than doing the opposite.
Could be worse though - some platforms (cough, iOS) are happy to break user apps every year and offload a constant maintenance burden onto many thousands of app developers, when a more stable ABI would save developers (and users) billions of dollars in aggregate.
In Linux’s defense, the userland abi is stable, which is no small feat in terms of absorbing pain in order to benefit their many users..
Not sure why the trade-off consideration led to a different outcome for in-kernel api’s, but given the work done to ensure the stability of the userland abi, I’m sure there is thought behind it..