On Fri, Oct 20, 2017 at 10:41:56AM -0400, Jim Quinlan wrote: > I am not sure I understand your comment -- the size of the request > shouldn't be a factor. Let's look at your example of the DMA request > of 3fffff00 to 4000000f (physical memory). Lets say it is for 15 > pages. If we block out the last page [0x3ffff000..0x3fffffff] from > what is available, there is no 15 page span that can happen across the > 0x40000000 boundary. For SG, there can be no merge that connects a > page from one region to another region. Can you give an example of > the scenario you are thinking of? What prevents a merge from say the regions of 0....3fffffff and 40000000....7fffffff?
