On Sun, 5 Feb 2017 10:46:29 -0800 Guenter Roeck <li...@roeck-us.net> wrote:
> On Fri, Jan 27, 2017 at 08:44:30PM +0200, Mike Rapoport wrote: > > When a non-cooperative userfaultfd monitor copies pages in the background, > > it may encounter regions that were already unmapped. Addition of > > UFFD_EVENT_UNMAP allows the uffd monitor to track precisely changes in the > > virtual memory layout. > > > > Since there might be different uffd contexts for the affected VMAs, we > > first should create a temporary representation for the unmap event for each > > uffd context and then notify them one by one to the appropriate userfault > > file descriptors. > > > > The event notification occurs after the mmap_sem has been released. > > > > Signed-off-by: Mike Rapoport <r...@linux.vnet.ibm.com> > > Acked-by: Hillf Danton <hillf...@alibaba-inc.com> > > Just in case 0day didn't report it yet, this patch causes build errors > with various architectures. > > mm/nommu.c:1201:15: error: conflicting types for 'do_mmap' > unsigned long do_mmap(struct file *file, > ^ > In file included from mm/nommu.c:19:0: > include/linux/mm.h:2095:22: note: > previous declaration of 'do_mmap' was here > > mm/nommu.c:1580:5: error: conflicting types for 'do_munmap' > int do_munmap(struct mm_struct *mm, unsigned long start, size_t len) > ^ > In file included from mm/nommu.c:19:0: > include/linux/mm.h:2099:12: note: > previous declaration of 'do_munmap' was here This was fixed in http://ozlabs.org/~akpm/mmots/broken-out/userfaultfd-non-cooperative-add-event-for-memory-unmaps-fix.patch?
