On 2019-01-22 at 23:02:22 -0500, Michael S. Tsirkin wrote: > On Wed, Jan 23, 2019 at 11:10:07AM +0800, Yi Zhang wrote: > > On 2019-01-22 at 22:01:58 -0500, Michael S. Tsirkin wrote: > > > On Wed, Jan 23, 2019 at 10:59:27AM +0800, Zhang, Yi wrote: > > > > From: "Zhang,Yi" <yi.z.zh...@linux.intel.com> > > > > > > > > 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'). > > > > > > > > A description of MAP_SYNC and MAP_SHARED_VALIDATE can be found at > > > > https://patchwork.kernel.org/patch/10028151/ > > > > > > > > In order to make sure that the file metadata is in sync after a fault > > > > while we are writing a shared DAX supporting backend files, this > > > > patch-set enables QEMU to use MAP_SYNC flag for memory-backend-dax-file. > > > > > > > > As the DAX vs DMA truncated issue was solved, we refined the code and > > > > send out this feature for the v5 version. > > > > > > > > We will pass MAP_SYNC to mmap(2); if MAP_SYNC is supported and > > > > 'share=on' & 'pmem=on'. > > > > Or QEMU will not pass this flag to mmap(2) > > > > > > How was this patch tested? Given the previous version apparently > > > passed the combination of flags ignored by Linux, > > > enquiring minds want to know. > > Ah. Sorry, We Have missed the flag MAP_SHARED_VALIDATE in V9, V8 and > > previous > > are tested. > > BTW I checked V8 and I don't see MAP_SHARED_VALIDATE there either. > So all the testing seems suspect at this point - > you want a test that fails all versions before V10.
Ah.. it is in V7, I fogot that after remove our own difination #define MAP_SYNC_FLAGS (MAP_SYNC | MAP_SHARED_VALIDATE) Sorry agin for that. > > > already fixed in the 2/4. > > > > > > > Changes in V10: > > > > * 4/4: refine the document. > > > > * 3/4: Reviewed-by: Stefano Garzarella <sgarz...@redhat.com> > > > > * 2/4: refine the commit message, Added MAP_SHARED_VALIDATE. > > > > * 2/4: Fix the wrong include header > > > > > > > > Changes in V9: > > > > * 1/6: Reviewed-by: Eduardo Habkost <ehabk...@redhat.com> > > > > * 2/6: New Added: Micheal: use sparse feature define RAM_FLAG. > > > > since I don't have much knowledge about the sparse feature, @Micheal > > > > Could you > > > > add some documentation/commit message on this patch? Thank you very > > > > much. > > > > * 3/6: from 2/5: Eduardo: updated the commit message. > > > > * 4/6: from 3/5: Micheal: don't ignore MAP_SYNC failures silently. > > > > * 5/6: from 4/5: Eduardo: updated the commit message. > > > > * 6/6: from 5/5: Micheal: Drop the sync option, document the MAP_SYNC. > > > > > > > > Changes in v8: > > > > * Micheal: 3/5, remove the duplicated define in the os_dep.h > > > > * Micheal: 2/5, make type define safety. > > > > * Micheal: 2/5, fixed the incorrect define MAP_SHARE on > > > > qemu_anon_ram_alloc. > > > > * 4/6 removed, we remove the on/off/auto define of sync, as by now, > > > > MAP_SYNC only worked with pmem=on. > > > > * @Micheal, I still reuse the RAM_SYNC flag, it is much > > > > straightforward to parse > > > > all the flags in one parameter. > > > > > > > > Changes in v7: > > > > * Micheal: [3,4,6]/6 limited the "sync" flag only on a nvdimm > > > > backend.(pmem=on) > > > > > > > > Changes in v6: > > > > * Pankaj: 3/7 are squashed with 2/7 > > > > * Pankaj: 7/7 update comments to "consistent filesystem metadata". > > > > * Pankaj, Igor: 1/7 Added Reviewed-by in patch-1/7 > > > > * Stefan, 4/7 move the include header from "/linux/mman.h" to "osdep.h" > > > > * Stefan, 5/7 Add missing "munmap" > > > > * Stefan, 2/7 refine the shared/flag. > > > > > > > > Changes in v5: > > > > * Add patch 1 to fix a memory leak issue. > > > > * Refine the patch 4-6 > > > > * Remove the patch 3 as we already change the parameter from "shared" > > > > to > > > > "flags" > > > > > > > > Changes in v4: > > > > * Add patch 1-3 to switch some functions to a single 'flags' > > > > parameters. (Michael S. Tsirkin) > > > > * v3 patch 1-3 become v4 patch 4-6. > > > > * Patch 4: move definitions of MAP_SYNC and MAP_SHARED_VALIDATE to a > > > > new header file under include/standard-headers/linux/. (Michael S. > > > > Tsirkin) > > > > * Patch 6: refine the description of the 'sync' option. (Michael S. > > > > Tsirkin) > > > > > > > > Changes in v3: > > > > * Patch 1: add MAP_SHARED_VALIDATE in both sync=on and sync=auto > > > > cases, and add back the retry mechanism. MAP_SYNC will be ignored > > > > by Linux kernel 4.15 if MAP_SHARED_VALIDATE is missed. > > > > * Patch 1: define MAP_SYNC and MAP_SHARED_VALIDATE as 0 on non-Linux > > > > platforms in order to make qemu_ram_mmap() compile on those > > > > platforms. > > > > * Patch 2&3: include more information in error messages of > > > > memory-backend in hope to help user to identify the error. > > > > (Dr. David Alan Gilbert) > > > > * Patch 3: fix typo in the commit message. (Dr. David Alan Gilbert) > > > > > > > > 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) > > > > > > > > Zhang Yi (4): > > > > util/mmap-alloc: switch 'shared' to 'flags' parameter > > > > util/mmap-alloc: support MAP_SYNC in qemu_ram_mmap() > > > > hostmem: add more information in error messages > > > > docs: Added MAP_SYNC documentation > > > > > > > > backends/hostmem-file.c | 6 ++++-- > > > > backends/hostmem.c | 8 +++++--- > > > > docs/nvdimm.txt | 29 ++++++++++++++++++++++++++++- > > > > exec.c | 7 ++++--- > > > > include/qemu/mmap-alloc.h | 20 +++++++++++++++++++- > > > > include/qemu/osdep.h | 21 +++++++++++++++++++++ > > > > qemu-options.hx | 4 ++++ > > > > util/mmap-alloc.c | 15 +++++++++++---- > > > > util/oslib-posix.c | 9 ++++++++- > > > > 9 files changed, 104 insertions(+), 15 deletions(-) > > > > > > > > -- > > > > 2.7.4 >
