There’s one answer in the article itself: "Modules maintainer Luis Chamberlain has recently been working on a problem where the arrival of a large number of re

There’s one answer in the article itself: "Modules maintainer Luis Chamberlain has recently been working on a problem where the arrival of a large number of requests to load modules in a short time can create difficulties for the memory-management subsystem. After some discussion, he posted a proposal for a mechanism that would simply limit the number of module-load operations that can be underway at any given time. Linus Torvalds quickly answered, reminding Chamberlain that semaphores ('a classic concurrency limiter') could be used for that purpose. The patch has since been reworked along those lines."