Commit a6bf53eb authored Feb 24, 2017 by Mike Rapoport Committed by Linus Torvalds Feb 24, 2017

userfaultfd: non-cooperative: add madvise() event for MADV_REMOVE request

When a page is removed from a shared mapping, the uffd reader should be
notified, so that it won't attempt to handle #PF events for the removed
pages.

We can reuse the UFFD_EVENT_REMOVE because from the uffd monitor point
of view, the semantices of madvise(MADV_DONTNEED) and
madvise(MADV_REMOVE) is exactly the same.

Link: http://lkml.kernel.org/r/1484814154-1557-3-git-send-email-rppt@linux.vnet.ibm.com


Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Reviewed-by: Andrea Arcangeli <aarcange@redhat.com>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Acked-by: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

parent d811914d

mm/madvise.c

+1 −0

Original line number	Diff line number	Diff line
		@@ -520,6 +520,7 @@ static long madvise_remove(struct vm_area_struct *vma,
		* mmap_sem.
		*/
		get_file(f);
		userfaultfd_remove(vma, prev, start, end);
		up_read(&current->mm->mmap_sem);
		error = vfs_fallocate(f,
		FALLOC_FL_PUNCH_HOLE \| FALLOC_FL_KEEP_SIZE,

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