On Thu, Apr 05, 2018 at 12:56:02AM -0700, Dan Williams wrote: > Yes, I think it is unfortunate that the failure mode is exposed to > software at all. The problem is that ADR is a platform feature that > depends on power supply requirements external to the NVDIMM device. An > SSD is different. It is a self contained system that can arrange for > the whole device to fail if the internal energy source fails and > otherwise hide this detail from software. My personal take, a system > designer that can specify and qualify an entire stack of components > can certainly opt-out of advertising the flush capability to the OS > because, like the SSD vendor, they control the integrated solution. A > platform vendor that allows off the shelf power supplies would in my > opinion be remiss not to give the OS the option to mitigate the > quality of some random power supply. It then follow that if the OS has > the ability to mitigate ADR failure it should be through a common > interface between fsdax and devdax.
That means IFF ADR can fail like this we can't treat it as stable storage and we must not support MAP_SYNC or equivalent device dax behavior, period. _______________________________________________ Linux-nvdimm mailing list Linux-nvdimm@lists.01.org https://lists.01.org/mailman/listinfo/linux-nvdimm
