On Tue, 27 Feb 2018 10:19:49 +0200 Mike Rapoport <[email protected]> wrote:
> Hi, > > These patches add ability to generate userfaultfd events so that their > processing will be synchronized with the non-cooperative thread that caused > the event. > > In the non-cooperative case userfaultfd resumes execution of the thread > that caused an event when the notification is read() by the uffd monitor. > In some cases, like, for example, madvise(MADV_REMOVE), it might be > desirable to keep the thread that caused the event suspended until the > uffd monitor had the event handled to avoid races between the thread that > caused the and userfaultfd ioctls. > > Theses patches extend the userfaultfd API with an implementation of > UFFD_EVENT_REMOVE_SYNC that allows to keep the thread that triggered > UFFD_EVENT_REMOVE until the uffd monitor would not wake it explicitly. "might be desirable" is a bit weak. It might not be desirable, too ;) _Is_ it desirable? What are the use-cases and what is the end-user benefit?
