> -----Original Message----- > From: owner-linux-mm@xxxxxxxxx [mailto:owner-linux-mm@xxxxxxxxx] On > Behalf Of Mike Rapoport > Sent: Tuesday, June 27, 2017 9:40 AM > To: Andrea Arcangeli <aarcange@xxxxxxxxxx> > Cc: Pavel Emelyanov <xemul@xxxxxxxxxxxxx>; linux-mm <linux- > mm@xxxxxxxxx> > Subject: Re: [RFC PATCH 0/5] userfaultfd: non-cooperative: syncronous events > > On Tue, May 16, 2017 at 01:35:57PM +0300, Mike Rapoport wrote: > > Hi, > > Any comments on this? > Shall I repost without the "RFC" prefix? > I have a use case for this feature exactly like what you have described. The process should be suspended until the event has been handled. I would like to test this if there is a rebased patchset out there somewhere? I'm using 4.13.0_rc3 from https://kernel.googlesource.com/pub/scm/linux/kernel/git/andrea/aa.git I wasn't able to apply the patches without heavy modification (mostly patch 3/5). Thanks for the work on this. > > These patches add ability to generate userfaultfd events so that thier > > 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. > > > > The first two patches just shuffle the code a bit to make subsequent > > changes easier. > > The patches 3 and 4 create some unification in the way the threads are > > queued into waitqueues either after page fault or after a > > non-cooperative event. > > The fifth patch extends 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. > > > > Mike Rapoport (5): > > userfaultfd: introduce userfault_init_waitqueue helper > > userfaultfd: introduce userfaultfd_should_wait helper > > userfaultfd: non-cooperative: generalize wake key structure > > userfaultfd: non-cooperative: use fault_pending_wqh for all events > > userfaultfd: non-cooperative: allow synchronous EVENT_REMOVE > > > > fs/userfaultfd.c | 205 ++++++++++++++++++++++++--------------- > > include/uapi/linux/userfaultfd.h | 11 +++ > > 2 files changed, 136 insertions(+), 80 deletions(-) > > > > -- > > 2.7.4 > > > > -- > To unsubscribe, send a message with 'unsubscribe linux-mm' in > the body to majordomo@xxxxxxxxx. For more info on Linux MM, > see: http://www.linux-mm.org/ . > Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a> -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>
