Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-02-01 Thread Alex Williamson
On Thu, 1 Feb 2018 18:17:44 +0800 Haozhong Zhang wrote: > On 01/31/18 19:02 -0800, Dan Williams wrote: > > On Wed, Jan 31, 2018 at 6:29 PM, Haozhong Zhang > > wrote: > > > + vfio maintainer Alex Williamson in case my understanding of vfio is > > > incorrect. > > > > > > On 01/31/18 16:32 -080

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-02-01 Thread Michael S. Tsirkin
On Wed, Jan 31, 2018 at 07:02:27PM -0800, Dan Williams wrote: > > Another question is how a user-space application (e.g., QEMU) knows > > whether it's safe to mmap a file on the DAX file system? > > I think we fix vaddr_get_pfn() to start failing for DAX mappings > unless/until we can add a "with

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-02-01 Thread Haozhong Zhang
On 01/31/18 19:02 -0800, Dan Williams wrote: > On Wed, Jan 31, 2018 at 6:29 PM, Haozhong Zhang > wrote: > > + vfio maintainer Alex Williamson in case my understanding of vfio is > > incorrect. > > > > On 01/31/18 16:32 -0800, Dan Williams wrote: > >> On Wed, Jan 31, 2018 at 4:24 PM, Haozhong Zhan

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Dan Williams
[ adding Michal and lsf-pci ] On Wed, Jan 31, 2018 at 7:02 PM, Dan Williams wrote: > On Wed, Jan 31, 2018 at 6:29 PM, Haozhong Zhang > wrote: >> + vfio maintainer Alex Williamson in case my understanding of vfio is >> incorrect. >> >> On 01/31/18 16:32 -0800, Dan Williams wrote: >>> On Wed, Jan

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Dan Williams
On Wed, Jan 31, 2018 at 6:29 PM, Haozhong Zhang wrote: > + vfio maintainer Alex Williamson in case my understanding of vfio is > incorrect. > > On 01/31/18 16:32 -0800, Dan Williams wrote: >> On Wed, Jan 31, 2018 at 4:24 PM, Haozhong Zhang >> wrote: >> > On 01/31/18 16:08 -0800, Dan Williams wro

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Haozhong Zhang
+ vfio maintainer Alex Williamson in case my understanding of vfio is incorrect. On 01/31/18 16:32 -0800, Dan Williams wrote: > On Wed, Jan 31, 2018 at 4:24 PM, Haozhong Zhang > wrote: > > On 01/31/18 16:08 -0800, Dan Williams wrote: > >> On Wed, Jan 31, 2018 at 4:02 PM, Haozhong Zhang > >> wrot

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Dan Williams
On Wed, Jan 31, 2018 at 4:24 PM, Haozhong Zhang wrote: > On 01/31/18 16:08 -0800, Dan Williams wrote: >> On Wed, Jan 31, 2018 at 4:02 PM, Haozhong Zhang >> wrote: >> > On 01/31/18 14:25 -0800, Dan Williams wrote: >> >> On Tue, Jan 30, 2018 at 10:02 PM, Haozhong Zhang >> >> wrote: >> >> > Linux 4

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Haozhong Zhang
On 01/31/18 16:08 -0800, Dan Williams wrote: > On Wed, Jan 31, 2018 at 4:02 PM, Haozhong Zhang > wrote: > > On 01/31/18 14:25 -0800, Dan Williams wrote: > >> On Tue, Jan 30, 2018 at 10:02 PM, Haozhong Zhang > >> wrote: > >> > Linux 4.15 introduces a new mmap flag MAP_SYNC, which can be used to >

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Dan Williams
On Wed, Jan 31, 2018 at 4:02 PM, Haozhong Zhang wrote: > On 01/31/18 14:25 -0800, Dan Williams wrote: >> On Tue, Jan 30, 2018 at 10:02 PM, Haozhong Zhang >> wrote: >> > Linux 4.15 introduces a new mmap flag MAP_SYNC, which can be used to >> > guarantee the write persistence to mmap'ed files suppo

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Haozhong Zhang
On 01/31/18 14:25 -0800, Dan Williams wrote: > On Tue, Jan 30, 2018 at 10:02 PM, Haozhong Zhang > wrote: > > 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 wit

Re: [Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-31 Thread Dan Williams
On Tue, Jan 30, 2018 at 10:02 PM, Haozhong Zhang wrote: > 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'). Wait, MAP_SYNC does not guarantee persist

[Qemu-devel] [PATCH v4 0/6] nvdimm: support MAP_SYNC for memory-backend-file

2018-01-30 Thread Haozhong Zhang
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