v2 is based on Eduardo's machine-next tree. Changes of
memory-backend-file are based on my previous patches in that tree.
Linux 4.15 introduces a new mmap flag MAP_SYNC, which can be used to
guarantee the write persistence to mmap'ed files supporting DAX (e.g.,
files on ext4/xfs file system mounted with '-o dax').
This patchset enables QEMU to use MAP_SYNC flag for memory-backend-file,
in order to guarantee the guest write persistence to backend files
supporting DAX.
A new auto on/off option 'sync' is added to memory-backend-file:
- on: try to pass MAP_SYNC to mmap(2); if MAP_SYNC is not supported or
'share=off', QEMU will abort
- off: never pass MAP_SYNC to mmap(2)
- auto (default): if MAP_SYNC is supported and 'share=on', work as if
'sync=on'; otherwise, work as if 'sync=off'
Changes in v2:
* Add 'sync' option to control the use of MAP_SYNC. (Eduardo Habkost)
* Remove the unnecessary set of MAP_SHARED_VALIDATE in some cases and
the retry mechanism in qemu_ram_mmap(). (Michael S. Tsirkin)
* Move OS dependent definitions of MAP_SYNC and MAP_SHARED_VALIDATE
to osdep.h. (Michael S. Tsirkin)
Haozhong Zhang (2):
util/mmap-alloc: support MAP_SYNC in qemu_ram_mmap()
hostmem-file: add 'sync' option
backends/hostmem-file.c | 39 ++++++++++++++++++++++++++++++++++++++-
docs/nvdimm.txt | 15 ++++++++++++++-
exec.c | 13 ++++++++-----
include/exec/memory.h | 4 ++++
include/exec/ram_addr.h | 6 +++---
include/qemu/mmap-alloc.h | 3 ++-
include/qemu/osdep.h | 16 ++++++++++++++++
memory.c | 6 ++++--
numa.c | 2 +-
qemu-options.hx | 21 ++++++++++++++++++++-
util/mmap-alloc.c | 24 ++++++++++++++++++++++--
util/oslib-posix.c | 2 +-
12 files changed, 133 insertions(+), 18 deletions(-)
--
2.15.1
