On Wed, Jul 26, 2017 at 12:16:11PM -0700, Dan Williams wrote: > Silently turn on DAX if HMAT says its ok? Yes, absolutely. I want my system to do the right thing by default, and if HMAT says bypassing the page cache is a clear advatange it should be the default. > I think we would instead > want a "-o autodax" for that case and then "-o dax" and "-o nodax" for > the force cases. Why? > I think it's easier to administer than the dax mount option. If > someone wants dax on only in a sub-tree they can set the flag on that > parent directory and have a policy in dax filesystems that children > inherit the dax policy from the parent. That seems a better > administrative model than trying to get it all right globally at mount > time. And why exactly? If DAX is faster for file a in directory X it will be just as fast for a file b in directory Y.
