]> git.baikalelectronics.ru Git - kernel.git/commit
userfaultfd: non-cooperative: add event for memory unmaps
authorMike Rapoport <rppt@linux.vnet.ibm.com>
Fri, 24 Feb 2017 22:58:22 +0000 (14:58 -0800)
committerLinus Torvalds <torvalds@linux-foundation.org>
Sat, 25 Feb 2017 01:46:55 +0000 (17:46 -0800)
commit897ab3e0c49e24b62e2d54d165c7afec6bbca65b
tree5fa7e09864d6c959cef33849f6cb10ed04e459e4
parent846b1a0f1db065a8479159dd8fecddb1ebf30547
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>
15 files changed:
arch/mips/kernel/vdso.c
arch/tile/mm/elf.c
arch/x86/entry/vdso/vma.c
arch/x86/mm/mpx.c
fs/aio.c
fs/proc/vmcore.c
fs/userfaultfd.c
include/linux/mm.h
include/linux/userfaultfd_k.h
include/uapi/linux/userfaultfd.h
ipc/shm.c
mm/mmap.c
mm/mremap.c
mm/nommu.c
mm/util.c