On Thu, Apr 12, 2018 at 12:43 PM, Linus Torvalds <torva...@linux-foundation.org> wrote: > On Thu, Apr 12, 2018 at 12:27 PM, Mathieu Desnoyers > <mathieu.desnoy...@efficios.com> wrote: >> The cpu_opv system call executes a vector of operations on behalf of >> user-space on a specific CPU with preemption disabled. It is inspired >> by readv() and writev() system calls which take a "struct iovec" >> array as argument. > > Do we really want the page pinning? > > This whole cpu_opv thing is the most questionable part of the series, > and the page pinning is the most questionable part of cpu_opv for me. > > Can we plan on merging just the plain rseq parts *without* this all > first, and then see the cpu_opv thing as a "maybe future expansion" > part. > > I think that would make Andy happier too. >
It only makes me happier if the userspace code involved is actually going to work when single-stepped, which might actually be the case (fingers crossed). That being said, I'm not really convinced that cpu_opv() makes much difference here, since I'm not entirely convinced that user code will actually use it or that user code will actually be that well tested. C'est la vie.
