On Wed, Aug 19, 2015 at 11:48:04PM +0100, Ross Zwisler wrote: > Add support for the "read flush" _DSM flag, as outlined in the DSM spec: > > http://pmem.io/documents/NVDIMM_DSM_Interface_Example.pdf > > This flag tells the ND BLK driver that it needs to flush the cache lines > associated with the aperture after the aperture is moved but before any > new data is read. This ensures that any stale cache lines from the > previous contents of the aperture will be discarded from the processor > cache, and the new data will be read properly from the DIMM. We know > that the cache lines are clean and will be discarded without any > writeback because either a) the previous aperture operation was a read, > and we never modified the contents of the aperture, or b) the previous > aperture operation was a write and we must have written back the dirtied > contents of the aperture to the DIMM before the I/O was completed. Is this operation expected to be implemented as a destructive invalidation (i.e. discarding any dirty lines from the cache) or also a writeback of any dirtylines as part of the invalidation? If its the former, we might want to give it a scarier name to ensure that it doesn't grow users outside of NVDIMM scenarios, since "flush" is used elsewhere for things like flush_dcache_page. Will -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
