diff options
| author | Mike Rapoport <rppt@linux.vnet.ibm.com> | 2017-02-24 14:58:22 -0800 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2017-02-24 17:46:55 -0800 |
| commit | 897ab3e0c49e24b62e2d54d165c7afec6bbca65b (patch) | |
| tree | 5fa7e09864d6c959cef33849f6cb10ed04e459e4 /include/linux/userfaultfd_k.h | |
| parent | 846b1a0f1db065a8479159dd8fecddb1ebf30547 (diff) | |
| download | lwn-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.tar.gz lwn-897ab3e0c49e24b62e2d54d165c7afec6bbca65b.zip | |
userfaultfd: non-cooperative: add event for memory unmaps
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.
[arnd@arndb.de: fix nommu build]
Link: http://lkml.kernel.org/r/20170203165141.3665284-1-arnd@arndb.de
[mhocko@suse.com: fix nommu build]
Link: http://lkml.kernel.org/r/20170202091503.GA22823@dhcp22.suse.cz
Link: http://lkml.kernel.org/r/1485542673-24387-3-git-send-email-rppt@linux.vnet.ibm.com
Signed-off-by: Mike Rapoport <rppt@linux.vnet.ibm.com>
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Hillf Danton <hillf.zj@alibaba-inc.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Pavel Emelyanov <xemul@virtuozzo.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'include/linux/userfaultfd_k.h')
| -rw-r--r-- | include/linux/userfaultfd_k.h | 18 |
1 files changed, 18 insertions, 0 deletions
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index 2521542f6c07..a40be5d0661b 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -66,6 +66,12 @@ extern void userfaultfd_remove(struct vm_area_struct *vma, unsigned long start, unsigned long end); +extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct list_head *uf); +extern void userfaultfd_unmap_complete(struct mm_struct *mm, + struct list_head *uf); + #else /* CONFIG_USERFAULTFD */ /* mm helpers */ @@ -118,6 +124,18 @@ static inline void userfaultfd_remove(struct vm_area_struct *vma, unsigned long end) { } + +static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, + unsigned long start, unsigned long end, + struct list_head *uf) +{ + return 0; +} + +static inline void userfaultfd_unmap_complete(struct mm_struct *mm, + struct list_head *uf) +{ +} #endif /* CONFIG_USERFAULTFD */ #endif /* _LINUX_USERFAULTFD_K_H */ |