Messages in this thread | | | Date | Fri, 2 Mar 2018 15:38:49 -0800 | From | Andrew Morton <> | Subject | Re: [PATCH 0/3] userfaultfd: non-cooperative: syncronous events |
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On Tue, 27 Feb 2018 10:19:49 +0200 Mike Rapoport <rppt@linux.vnet.ibm.com> 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?
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