[$] Implementing alignment guarantees for kmalloc()

kmalloc() is a frequently used primitive for the allocation ofsmall objects in the kernel. During the 2019Linux Storage, Filesystem, and Memory Management Summit, VlastimilBabka led a session about the unexpectedalignment problems developers face when using this function. After a fewmonths he has come back with the secondversion of a patch set implementing a natural alignment guarantee forkmalloc(). From the strong opposition it facedinitially, it seemed that the change would not get accepted. However, itended up in Linus Torvalds's tree. Let's explore what happened.