On 08/13/2015 05:48 PM, Boaz Harrosh wrote: <> > There is already an object that holds a relationship of physical > to Kernel-virtual. It is called a memory-section. Why not just > widen its definition? > BTW: Regarding the "widen its definition" I was thinking of two possible new models here: [1-A page-less memory section] - Keep the 64bit phisical-to-kernel_virtual hard coded relationship - Allocate a section-object, but this section object does not have any pages, its only the header. (You need it for the pmd/pmt thing) Lots of things just work now if you make sure you do not go through a page struct. This needs no extra work I have done this in the past all you need is to do your ioremap through the map_kernel_range_noflush(__va(), ....) [2- Small pages-struct] - Like above, but each entry in the new section object is small one-ulong size holding just flags. Then if !(p->flags & PAGE_SPECIAL) page = container_of(p, struct page, flags) This model is good because you actually have your pfn_to_page and page_to_pfn and need not touch sg-list or bio. But only 8 bytes per frame instead of 64 bytes But I still think that the best long-term model is the variable size pages where a page* can be 2M or 1G. Again an extra flag and a widen section definition. Is about time we move to bigger pages, throughout but still keep the 4k page-cache-dirty granularity. Thanks Boaz -- 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>