Kernel Watch
Jon Masters summarises the latest happenings in the Linux kernel, so you don’t have to.
Jon Masters
Paul McKenney posted a thread titled “Litmus test for question from Al Viro” in which he explored a “fun question regarding barriers” from Al. Such questions arise as developers seek to understand how particular pieces of code might run on modern multi-processor (multicore) machines with shared memory. The interactions can be complex and are often explored in the form of “litmus test” snippets demonstrating behaviours.
Paul is well known for his work on RCU (Read Copy Update), a mechanism he originally co-invented for more efficient shared data structures, and for his championing of the effort to bring researchers into the kernel community to write a formal memory model for Linux. As a result, he’s the typical go-to person for certain questions, including those from Al, who’s a well-known developer in the Linux VFS (Virtual File System) layer. Thus, it’s likely the sequence Al posted in example form is based upon real-world filesystem code: