[ adding Jeff directly since he has also been looking at infrastructure to track when MAP_SYNC should be disabled ] On Wed, Apr 25, 2018 at 7:21 AM, Dan Williams <dan.j.williams@xxxxxxxxx> wrote: > On Wed, Apr 25, 2018 at 4:24 AM, Pankaj Gupta <pagupta@xxxxxxxxxx> wrote: >> This patch adds virtio-pmem driver for KVM >> guest. > > Minor nit, please expand your changelog line wrapping to 72 columns. > >> >> Guest reads the persistent memory range >> information from Qemu over VIRTIO and registers >> it on nvdimm_bus. It also creates a nd_region >> object with the persistent memory range >> information so that existing 'nvdimm/pmem' >> driver can reserve this into system memory map. >> This way 'virtio-pmem' driver uses existing >> functionality of pmem driver to register persistent >> memory compatible for DAX capable filesystems. > > We need some additional enabling to disable MAP_SYNC for this > configuration. In other words, if fsync() is required then we must > disable the MAP_SYNC optimization. I think this should be a struct > dax_device property looked up at mmap time in each MAP_SYNC capable > ->mmap() file operation implementation.
