[RFC PATCH 0/5] userfaultfd: non-cooperative: syncronous events

["Mike Rapoport" <rppt@linux.vnet.ibm.com>]

Hi,

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@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>