On Fri, Jan 22, 2016 at 01:48:08PM +0000, Chris Brandt wrote: > I believe the motivation for the new DAX code was being able to > read/write data directly to specific physical memory. However, with > the AXFS file system, XIP file mapping was mostly beneficial for direct > access to executable code pages, not data. Code pages were XIP-ed, and > data pages were copied to RAM as normal. This results in a significant > reduction in system RAM, especially when used with an XIP_KERNEL. In > some systems, most of your RAM is eaten up by lots of code pages from > big bloated shared libraries, not R/W data. (of course I'm talking about > smaller embedded system here) OK, I can't construct a failure case for read-only usages. If you want to put together a patch-set that re-enables DAX in a read-only way on those architectures, I'm fine with that. I think your time would be better spent fixing the read-write problems; once we see persistent memory on the embedded platforms, we'll need that code anyway. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>