On Wed, Feb 19, 2020 at 10:43:05AM -0500, Mathieu Desnoyers wrote: > The regression I'm talking about here is that CONFIG_CPUSET=y changes the > behavior of the sched_setaffinify system call, which existed prior to > cpusets. > > sched_setaffinity should behave in the same way for kernels configured with > CONFIG_CPUSET=y or CONFIG_CPUSET=n. > > The fact that cpuset decides to irreversibly change the task affinity mask > may not be considered a regression if it has always done that, but changing > the behavior of sched_setaffinity seems to fit the definition of a regression. We generally use "regression" for breakages which weren't in past versions but then appeared later. It has debugging implications because if we know something is a regression, we generally can point to the commit which introduced the bug either through examining the history or bisection. It is a silly bug, for sure, but slapping regression name on it just confuses rather than helping anything. -- tejun
